"S" wrote in message
et...
silver is a better conductor than gold, but will tarnish very easily,
might
now be a good idea for what you are intending

I thought that silver oxide was a decent conductor, which is why it is
sometimes used as a plateing material.

jim
N8EE

On Fri, 16 Apr 2004 20:40:53 -0400, "JLB"
wrote:


"S" wrote in message
. net...
silver is a better conductor than gold, but will tarnish very easily,
might
now be a good idea for what you are intending

I thought that silver oxide was a decent conductor, which is why it is
sometimes used as a plateing material.

Hi All,

It hardly matters unless you are speaking of switch contacts.
Insulated wire's insulation is absolutely unconductive, and yet in the
context of antennas it doesn't impact the wire's capacity to carry
current.

Oxidation products only become a problem at interfaces where they
either resist current between the joined conductors, or create a
semiconducting barrier.

The technician is taught to clean surfaces of tarnish to bring bright
metal into contact. Then crimp them (or twist the wire - same thing)
for a gas tight seal. Then solder them to weather proof the seal
(solder is never meant to be a mechanical join or the conductive
path). Common practice allows for solder to provide more
functionality than what I describe - this does not elevate the method.
Barring the final solder, switch contact faces must meet the same
conditions of bright metal and gas tight seals. This is often
achieved by pressure (some mistake the so-called "wiping" action as
meaning to scrub the oxide away - a useful metaphor but only that;
otherwise switches would self demolish in very few operations) and a
sustaining current (wet vs. dry contacts).

73's
Richard Clark, KB7QHC

What about silver plated RF connectors?

As far as that goes, there are also plenty of gold plated connectors out
there.

Jim
N8EE

"Richard Clark" wrote in message
news
On Fri, 16 Apr 2004 20:40:53 -0400, "JLB"
wrote:


"S" wrote in message
. net...
silver is a better conductor than gold, but will tarnish very easily,
might
now be a good idea for what you are intending

I thought that silver oxide was a decent conductor, which is why it is
sometimes used as a plateing material.

Hi All,

It hardly matters unless you are speaking of switch contacts.
Insulated wire's insulation is absolutely unconductive, and yet in the
context of antennas it doesn't impact the wire's capacity to carry
current.

Oxidation products only become a problem at interfaces where they
either resist current between the joined conductors, or create a
semiconducting barrier.

The technician is taught to clean surfaces of tarnish to bring bright
metal into contact. Then crimp them (or twist the wire - same thing)
for a gas tight seal. Then solder them to weather proof the seal
(solder is never meant to be a mechanical join or the conductive
path). Common practice allows for solder to provide more
functionality than what I describe - this does not elevate the method.
Barring the final solder, switch contact faces must meet the same
conditions of bright metal and gas tight seals. This is often
achieved by pressure (some mistake the so-called "wiping" action as
meaning to scrub the oxide away - a useful metaphor but only that;
otherwise switches would self demolish in very few operations) and a
sustaining current (wet vs. dry contacts).

73's
Richard Clark, KB7QHC

On Sat, 17 Apr 2004 21:45:46 -0400, "JLB"
wrote:
What about silver plated RF connectors?

As far as that goes, there are also plenty of gold plated connectors out
there.

Hi Jim,

What about them indeed? If they don't meet the requirements of bright
untarnished metal, then they need pressure mating (all the good ones I
know specify this - but deeply embedded within their core
manufacturing specs) e.g. Amp RF connectors:
"Insufficient contact force will give rise to metal to oxide
junctions. The classic rectifiers were metal oxide by
composition.

"The applied mounting force is concentrated in the surface area of
the protrusion which, on engagement with the panel, punctures the
existing oxide layer to give a metal-to-metal, gas-tight
junction."

The gold plating, presumably, precludes giving rise to oxidation
products; however, pressure then becomes an issue of mating surface
area (Ohms). Every precision contact used for Resistance and Voltage
standards (in the old days) were tapered brass plugs that could be
wedged into the jack with a twist (pressure). They knew about gold
then too, but brass served admirably.

73's
Richard Clark, KB7QHC