sw wire oxidation

[k9rzz]

Not mentioned, perhaps common knowledge to all here, but RF does travel on the surface of the wire, so ... ?

The only problems I've ever had with oxidized wire HF antennas was a temporary antenna made from old speaker wire. All those strands got lightly oxidized over time while laying in the basement and when strung outside and hooked up, the AM broadcast interference was horrible. Swapped that wire out with #14 solid and the interference disapeared. FWIW

 

[LtDoc]

The only oxidation I would worry about is at 'contact' points, connections etc. After that, I guess it matters if you don't like the color green. Most antennas made with copper will out live their owners if they don't have accidents of some kind.
- 'Doc

 

[ridgescan]

Thanks all for the advice and perspectives

 

[KC4RAF]

In the many years playing around

with copper long wire SW antennas, I never had a problem with oxidation on the wires and receiving/transmitting. True, to some extent that the current travels on the surface of the wire, but oxidation does not hinder the signal, at least in my experiences with long wire antennas. Now at the terminal ends, that was a different story. But overall, what Warren posted is correct. He's been around this stuff probably as long as me and he does know what he's talking about. And as for the oxidation causing noise and hinder reception, please give an example of this happening.
Old hams did polish their antennas way back when, because they felt it would help the signal jump off the element(s) easier! lol But as 'Doc posted, your terminals need attention time to time.
Guys, I wouldn't worry too much about the oxidation on the long wires, unless you feel the need for extra work...

edit:
My asking for example of noise problem caused by oxidation, one must remember that reception in the RF world happens very fast and can change minute to minute; bad reception a minute ago to great reception this minute, so an example would be hard to produce.

 

[kb2vxa]

Here I am chuckling again, misinformation ABOUNDS! Most have it right, thanks for your understanding and the quotes that saved me from aggravating repetition.

Replacing a copper wire antenna with new improves reception, in your imagination. I'll cut you some slack, could be there were unsoldered connections that weathered and since oxides are poor conductors it could cause problems. My connections were all soldered, I never replaced anything and my antennas green as they were gave many years of reliable service.

Right, well sort of, old hams are experienced hams so we do polish antennas. Aluminium corrodes easily so they have to be disassembled and joints given the steel wool treatment periodically. Then there is antenna grease, we bring it out around the first of April.

That "advice" from a landscaper almost had me rolling. Copper buried in acid soil will turn black, copper oxide is a familiar green but copper sulfide is black and brittle which may give a false impression. I guess he didn't look close enough to see the copper underneath was still copper... what does a LANDSCAPER know? (;->)

Then more giggles from the notion that copper wire loses conductivity. If that were the case salt air corrosion here at the shore would have rendered the power lines insulators long ago. Older stuff from when the power company still used copper has been up since God knows when, a nice pretty green but still we have electricity.

I generally go to an electrical supply house for wire, fittings, grounding stakes and general stuff, I shop around for coax and RF fittings but when it comes to specialty items it's Wireman to the rescue. I have have to add my endorsement because I've been to their hamfest table here and there and they generally have just what I need. Oh and BTW they're the antithesis of Rat Shack if you get my drift.

 

[ridgescan]

I'm like the frikkin wind here lol
thanks for the last two posts-leaving it be here

 

[nanZor]

The only oxidation problem I ever ran into was when using cheap stranded speaker wire outdoors which almost looked green under the clear covering. Although my connections at the radio and far end were mechanically solid, the oxidation ate through a couple of strands many feet down the line, although I couldn't see it physically.

The result was that the very small flexing of the antenna outdoors made these bad strands intermittent causing all sorts of problems - like scraping a whip antenna against another metal object. The breaks were about 3 feet inwards when I took the time to try and find it by flexing the wire a little bit foot by foot.

It looked good on an ohmmeter when the wire was very still on the ground and a few of the strands were physically ok, but once in the air, the flexing revealed that some strands were intermittent.

The solution was to replace it with higher-quality wire that could stand the flexing and a bit of exposure without deteriorating so fast.

 

[kb2vxa]

Yeah Ridge; Let it be, let it be, let it be, let it be. Whisper words of wisdom, let it be. (;->)

Hertzian, the only reason you had trouble is because you didn't use oxygen free speaker wire. Ask any audiophool, it just sounds better.

"Old hams did polish their antennas way back when, because they felt it would help the signal jump off the element(s) easier! lol"

Stop laughing for a minute rfdav and read my above post again. Polishing doesn't do that, what do you think antenna grease is for?

 

[Sol100]

Fence Wire ?

I know fencing wire has a pretty high resistance due to the impurities in the wire. Years ago a lot of old timers used to use it in battery chargers to drop the voltage from 12V to 6V. It would be interesting to see what affect the higher resistance has on RF reception?
Remember when joining two dissimilar materials electrolysis can take place and this can cause damage of the joints or at least very high resistance.
Also solid copper to me is more preferable that fine multi strand. The layer of copper oxide on a conductor does protect it over time but that’s not before the outside layer of copper is changed chemically. Some of the fine multi strand wires tend to get very week and even brake because each individual strand suffers the oxidisation process. In total that means that a greater percentage of the conductor is damaged and weakened.

Sol

 

[nanZor]

I know fencing wire has a pretty high resistance due to the impurities in the wire. Years ago a lot of old timers used to use it in battery chargers to drop the voltage from 12V to 6V. It would be interesting to see what affect the higher resistance has on RF reception?

A lot depends on how long the wire is, and how low in frequency you go (skin depth issues at low frequencies), and how tolerable any sort of loss may be to your antenna design.

Qrz . com has a good thread with some contributors like W8JI , VK1OD and others about "galvanized electric fence wire or copper for loop" that is interesting.

 

[LtDoc]

In most cases, all this just isn't an 'issue'. Keeping that corrosion/oxidation to a minimum at connections is nice, but after that it really doesn't have much affect. Enjoy worrying about that sort of thing? Well, knock yourself out with it! I'll waste my worry on something else...
- 'Doc

 

[k9rzz]

My experience with fence wire was a 1,500 ft wire put up temporarily through a woods and over a pond. My folks had a lake cottage on a dead end road, so a friend and I strung it up in a neighboring cow pasture/woods. Worked GREAT right down to longwave where we heard daytime stuff we never imagined. Very directional on AM BC with awesome signals. FWIW.

 

[majoco]

Just one slightly OT question....

If you use uninsulated bare copper, do you get 'rain static' due to the little discharges every time a raindrop hits the wire?

.....and if the wire has now gone green with a supposedly insulating outer coating, does the rain static go away?


Hmmm....

 

[KMG54]

My experience with fence wire was a 1,500 ft wire put up temporarily through a woods and over a pond. My folks had a lake cottage on a dead end road, so a friend and I strung it up in a neighboring cow pasture/woods. Worked GREAT right down to longwave where we heard daytime stuff we never imagined. Very directional on AM BC with awesome signals. FWIW.

That is my experience too. If I only had a fifty foot run I would look at copper, but with 400 foot in a inverted vee and sloping it works great!

 

[Sol100]

Old telephone lines

Along side my cousin’s farm ran the old disused telephone line aerials, miles of them. I often wondered what would be the result if I hooked up a radio. Not very scientific and it would go against all the radio theory that I know. But it was one of those things that a voice inside says "you must try it", sadly another louder voice, the wife said "No way". I never did get to stop the car and play.
I suppose it's what ever works for you.