ee's please reply - (or those who think think they may know)

This is a sort of unremarkable finding. Tesla did more-or-less the same thing years ago. There are a myriad of issues here, not the least of which is the effects on human tissue that such a technique might engender when scaled sufficiently to be useful (assuming it is practical as an engineering matter). See the comments at the end of this article:

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Reply to
Tim Daneliuk
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Certainly, but invention does not take place (so to speak) in a vacuum. No innovation can violate demonstrated physical properties. Maxwell's Equations that describe the governance of electromagnetic fields have been with us for quite some time and seem unlikely to be wrong. So, if we are to "innovate" in matters as discussed here, there are really only two choices: A) There must be a fundamental breakthrough in physics that changes all the known rules (possible but unlikely) or B) We find a better way to engineer around the known constraints of physics.

What Tom wants makes sense, but only in limited contexts, at least as physics is understood today. Moreover, all engineering is a tradeoff between features, time (to go to market) and *cost*. A modern wire manufacturing facility is not a cheap thing to build. To justify what Tom suggest, there has to be concrete economic advantage. If copper cost, say, $3M per oz, that would be a compelling economic driver. But it doesn't and the economics seems - at least at a casual glance - to favor the status quo.

BTW, note that the transition from vacuum tubes to semiconductors was not a fundamental shift in our understanding of amplification or oscillation. It was a fundamental breakthrough in process technology. That is, we discovered how to do what vacuum tubes were doing in a more compact, and ultimately, less expensive way as a matter of

*engineering*. There was, of course, a corresponding breakthrough in our understanding of the physics of semiconductors. Even so, semiconductors never completely replaced vacuum tubes. Radio transmitters of any large size still use tubes (valves to those of you in the rest of the Anglosphere) because there are no transistors of which I am aware, at least, than can deliver 50KW of RF into an antenna.
Reply to
Tim Daneliuk

Tim Daneliuk wrote in news: snipped-for-privacy@eskimo.tundraware.com:

*trim*

Those teeny little magic dwarfs smoke a lot, don't they?

Reply to
Puckdropper

At 60 Hz, the skin depth is inches (and wire a fraction of an inch across is the norm). At higher frequencies, you see silver-plated wire and most CATV cable is copper-plated iron for the central wire. So, common wire products DO use less conductive materials in the core.

Reply to
whit3rd

At the Boston Museum of Science, there is a live demo where an operator in a metal cage is hit by lightning while his or her hands are against the inside of the cage. The lightning travels down the outside of the cage.

Well worth the trip if in Boston!

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Reply to
B A R R Y

High-powered radar has been all solid state for some time. Many, many peak KW at low duty cycle into the antenna. Continuous (AM, FM, TV) at high power uses a number of smaller amplifiers with a split feed at the input and a combiner at the output.

Back in 1975, I worked with solid state amplifiers in the ultrasound range (30-50KHz) that delivered bursts of a single tone into a piezo transducer. Several peak KW with two TO-3 transistors and no heatsink!

Today, Harris Broadcast sells an all solid-state 40KW FM broadcast transmitter. I'm sure there are others, and for AM and TV as well.

Reply to
Art Greenberg

And this is exactly the reason why smaller coils and cavities are often silver plated copper. the whole thing doesnt need to be silver, just the skin.

dickm

Reply to
dicko

This is _very_ well understood. If an "EE" doesn't understand this, I can only assume they've spent their life working on 60Hz kit and never gone near a radio.

Electrons go everywhere. At low frequencies, a substantial number are in the middle of the conductor, and that might be a thick conductor.

If you consider a high frequency though, there's an exponential (i.e. gradual) fall off with depth. This leads to "skin effect" and is why VHF radios used to use Litz wire (many strands, so much more "surface to diameter" ratio) and why VHF / UHF uses silver plating on the surface of conductors. Above UHF, it's mostly waveguides rather than conductors.

Reply to
Andy Dingley

No, they don't usually smoke at all.

Until they all stop working for a massed fag break, where they now have to go outside to do it.

Reply to
Andy Dingley

I remember building 40M antennas out of Copperweld wire. A steel core with a copper skin. You had to be careful with that stuff. Cut the ties holding the coil of wire together and, BOING, like letting go of a spring, you were immediately standing in the middle of a tangled mess of wire that you didnt dare kink. It would take hours to untangle.

dickm

Reply to
dicko

In high frequency situations we don't Tom. Conductors for such things as radio towers are often hollow core conductors.

Reply to
Mike Marlow

Not with the intent of giving offence but -

Yours is a particularly baseless argument, seemingly overly fond of your own insightfulness.

Reply to
Mike Marlow

That has the sound of stating that the EE's are missing the obvious benefits of applying these principles universally. As you so properly stated though, they are being applied in the relevant industries. The operative part of that is the word "relative".

Reply to
Mike Marlow

I think you're making a fundamentally mistaken assumption here, that engineers are people "who aren't really creative via personality." If nothing else, the thousands of patents granted every year would suggest otherwise. Creativity occurs in other areas besides the fine arts, you know.

Reply to
Doug Miller

Copper clad steel ground rods are common.

HF tank circuits using silver plated copper are common.

Nothing novel about what you are saying. As the table of skin depths shows, the value is very dependent on the frequency of use. For DC or normal house wiring there is no benefit.

John

Reply to
John Siegel

You're post has brought out some erudition on the subject of electical engineeering. If this keeps up I suspect our NG will be discussing entropy and a deeper understanding of gravity, with respect to woodworking of course. Joe G

Reply to
GROVER

Imagine my surprise.....

Reply to
Robatoy

Because it's cheaper? I used to work, many eons ago, for American Steel and Wire in North Chicago. Plain old drawn copper or aluminum or whatever was cheap to produce. Plating was expensive. I don't know if that's still the case or not, but I'd guess it is.

Reply to
Larry Blanchard

Interesting. I used to service marine Radars, and while their peak output power was in the 10-50 KW range, their average power was far lower because of the low duty cycle. When you say that radars have been solid state for some time, does that mean magnetrons and klystrons are no longer in the picture? (Not arguing, just curious.)

Reply to
Tim Daneliuk

Excellent point.

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Reply to
B A R R Y

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