Silvered wire for inductors?

[Edward Cain]

   I have a Johnson Matchbox (275 W version) minus the inductor and I'm thinking of winding a coil myself.
   My question is what type of wire will I need? Silvered? Tinned? Bare?

    Any recommendations?

Ed

[KM1H]

Tinned or bare copper is fine, silver is strictly for looks at anything below UHF.

Carl

[k4kyv]

The EF Johnson edge-wound coil in my 80m tuner looked like it was nickel plated, not silver, when I first installed it.  After 30 years in the outdoor air and condensation (even though it was protected from direct exposure to the elements by the old Dawg House), every trace of the plating is now gone. All that remains is bare brownish copper. Silver usually turns black, but supposedly the oxide is just as good a conductor as bright silver.  I agree with Carl that there would unlikely be any detectable difference between bare copper and any kind of plating at MF/HF.

The 160m tuner coil came out of an old broadcast transmitter.  It is silver plated, but coated with some kind of clear lacquer, and other than dirt accumulation,  looks the same as it did the day I put it in. The enamel insulation on "magnet" wire also protects the copper from oxidation.

That would be a good experiment to try if anyone happens to have two identical coils, one plated and one not: swap them out to see if there is any perceptible difference.   I would bet on none.

[w3jn]

The black junk on silver is NOT silver oxide but rather silver sulfide which is not a conductor.

[Ed/KB1HYS]

Perhaps you should spray a bit of Clear Coat or something over the coils once they are set up (tapped correctly and soldered).

[KA2DZT]

The black junk on silver is NOT silver oxide but rather silver sulfide which is not a conductor.

I'm not a chemistry expert, but, if the silver turned black from being in the air where there is oxygen, where did the sulfur come from to make the black deposit silver sulfide?  Maybe salty air??

What's the answer?

Fred

[KF1Z]

The black junk on silver is NOT silver oxide but rather silver sulfide which is not a conductor.

I'm not a chemistry expert, but, if the silver turned black from being in the air where there is oxygen, where did the sulfur come from to make the black deposit silver sulfide?  Maybe salty air??

What's the answer?

Fred

Hydrogen Sulfide in the atmosphere.

[k4kyv]

The black junk on silver is NOT silver oxide but rather silver sulfide which is not a conductor.

http://www.blitzinc.net/category/info.how_why_silver_tarnishes/

I wonder if it's a non-conductor or a poor conductor.  If it is a non-conductor, it would be like any other insulation and have no noticeable effect on the  coil. Maybe that's why I have often heard it said that the black stuff conducts just as well as bright silver.  But if it is a poor conductor, because of the skin effect it would reduce the Q of the coil.

[KM1H]

There was a good thread over on the Amps reflector about a month or less ago on this subject and several professional papers and citations were listed.

Check the archives for the full discussion.