The AM Forum

A feature on our local newspaper financial page lists commodity prices.  From time to time I check on the price of copper.  A few weeks ago it was $2.34/lb.  In recent weeks the price has been rising a few pennies every day. This morning I noticed that it was up to $2.73/lb.

This could be good news and bad.  It could signal that the economy is improving.  I have noticed that the price of copper closely follows the state of the economy, and is probably a better indicator than the daily stock market numbers.  I purchased the wire for my radial system in 1974 at a bargain price when the economy hit a  major slump back then.  I recall that copper prices had inflated around 400% two years ago just before the bubble broke and we had the big crash.

The bad news is that copper may be once more on its way to becoming unaffordable for useful things like ground systems, and copper theft may again become rampant.  It most likely signals a further devaluation of the dollarette, since $1 now buys less than it did previously.  Other prices may soon follow.

Now there will be more electrical substation rip-offs

Fred

In the past few weeks the dollar has been taking a beating mostly because of the foreign investors thinking that we about to monitize the debt or default.  That is why the Treasury Secretary and Secretary of State have been going from one country to another to assure them we won't default and their investments are safe.

The countries are hedging their bets by buying commodities mostly oil and gold.  China has been increasing its gold holdings now for about the past year and slacked off after the recession started but has now restarted purchasing it.  Last week the dollar would only bring 93 and change yen.  Yesterday it was 95 and I haven't looked today. 

China and a few others are worried and that plays a role in commodities prices. 

Thurs. 06 AU: $2.80/lb

SI $14.86, GC $960.70, but more important gasoling is $2.06 all prices at close of Nymex.

and youtube surveillance vids to serve as lessons as to why stealing live copper is a bad idea..

I just checked 500 Ft spools of #12 THHN stranded at Menard's this weekend.  Still $40.00.

Of course, not too long ago...that same spool was only $15.00, then went up to $67.00.   Romex and other wiring products are still very expensive, but down somewhat from the peak.

73,  Jack, W9GT

I checked at Lowes about a month or two back. A 500 foot roll then was only $20.00. I have to see that it is now.

That was the price for #14 solid at Menard's this past Saturday.  #14 would still probably be OK, although I prefer stranded for antenna stuff.  I think #14 stranded was $25.00 for a 500 Ft roll.

73,  Jack, W9GT

Yep. It was #14 THNN.

Stranded is the way to go if you're not going to use Copperweld. Back in the 80s I made the mistake of using some solid copper (14 ga. I think) wire from a 500 ft spool to make my first 80m dipole. No support in the center, stretched between a tree and a wooden tower. Wasn't long before the flat ant started looking like a big grin, probably ended up as a 90m or more dipole by the time I cut it down. An early lesson in soft-drawn copper wire. Fortunately the KWM-2A tuned it easily and didn't object.

Trying to recall what the gripe was over using electric fence wire as it was always dirt cheap. Seem to recall that being galvanized made it difficult to get a good solder joint. In the even copper goes nuts again, what alternatives exist? Beyond substations, that is....

Velocity of propagation is different for galvanized steel wire, but you can use it, I think the antenna ends up being a little shorter, IIRC.  Copperweld works great, if you can find it...even welding wire...some of which is copper coated steel, but it is typically only about 18 or 19 guage.  That stuff makes good radial wire though.

73,  Jack, W9GT

Probably more important is the conductivity.

The only way to go with large wire antennas is stranded Copperweld. MUCH easier to deal with than single strand Copperweld, which will play Python on you.

Davis RF and the Wireman carry it. The 7-strand #14 stuff is .11/foot and the 19 strand #14 tinned Copperweld is only .13/foot. It will NEVER break or stretch. I've had my 300' long double zepp up for 10 years in hurricane winds...Made of Belden 7-strand #14 Copperweld. I wouldn't use soft-drawn copper wire for anything larger than a 40 meter dipole if expecting it to last.

At work am buying copper cylinders to build large cavity amplifiers for VHF out of. We have an order our for forgings that will be machined, these are 11 to 13 inch diameter, totaling about $50K! I cannot imagine what it would have been for a solid ingot of copper, hogging out the center with a machine, like was done years ago.

About the only thing soft-drawn bare copper wire is good for is ground radials.

But I seem to recall reading that soft-drawn can be converted to hard-drawn by stretching it.  There is a specific limit to its elasticity kind of like that of a rubber band, and if you stop stretching just prior to that limit, you will have hard-drawn that will no longer be prone to stretching.  If you try to force it to stretch further beyond that limit, that weakens the wire and it will be prone to break.  The trick is to determine just the right moment to stop stretching.

I use copper clad steel for my feedlines and antennas simply because I was able to acquire a few thousand feet of #10 and #8 at no cost.  Like EHS guy wire, it is a PITA to work with and can be dangerous if you are not careful, but once erected, it is virtually bulletproof.

Copperweld is great stuff.  But,  I pmce took down  a  stranded CW amtemma that  had been up for about six years.  The copper coating  was disintegrating,  and the surface was mostly composed of rust.   I would  use solid only.  Or if forced to use stranded,  would choose CW with the fewest possible number of strands available.

My assumption is that the sopper coating is roughly a fixed percentage of the diameter of the steel core.  The smaller diameter of each individual steel wire of the stranded CW means (to me) that the copper coating of each strand is MUCH thinner,  and therefore much more vulenrable to perforation/rust.

AlumoWeld(tm) is similar in nature to CW,  but it is said that alunumun oxide corrosion is self-limiting,  and thus is said to protect the steel core.  However,  AW is much harder to buy in small quantities.  YMMV    Vic

Copper clad steel electric fence wire is worthless.  The copper coating is so thin that the steel core actually rusts through to the surface after not-so-prolonged exposure to the elements.  I buried some of my #10 copperweld for a radial system in the early 70's. Occasionally I still find a piece buried, and when I pull it up, the copper cladding is still almost intact.  It is coated with a thin layer of greenish brown crud, but very little of the copper is gone, and a little light sanding brings back bright copper.

I notice my #8 copperweld has about the same thickness of copper cladding as does the #10, but the steel core is larger diameter, making the percentage of copper less, but it still should last about as long under similar conditions.

I noticed to-day that copper was down to $2.70 something.  But the US dollarette was down to about $1.09 Canadian.  A few weeks ago it was running close to $1.20 Canadian.

I remember that 400% increase a few years back... a 250' roll of 12/2 with ground used to be about $29 at Home Depot. The next time I checked it was over $100  :o
eventually dropped back to the 60s... not sure what it is now but I will need to buy a roll soon anyway.

Don't know if there is any correlation but scrap steel prices seem to be at an all-time high. I just took some junk to the recycling place and got $120 a ton for it! last summer was $50.

-Charles

Classic case of two steps forwards, one step backwards.

I took about 400 lbs of #1 copper to the junk yard yesterday and there paying $1.80/lb.
Regards,
Gary