# Free electicity - crystal radio

berkeman
Mentor
I do not believe that story. *shrug*

I guess that I believe it. But I'm a sucker for a happy ending!

I do not believe that story. *shrug*

neither do i! it sounds like the most dramatic contrived thing ever. "Let's get back to work! <slams physics book down>" you've got to be kidding me.

why in the world would someone make something like this up
this is seriously so weird.

You can get electricity from the phone line in your wall.

You can get electricity from the phone line in your wall.

what can i do with 100mW

I'm not saying that you can do something with it really. Just saying that that electricity you are indirectly paying for.

I tried what berkeman said about capacitive coupling but I didn't get any reading on my voltmeter. Maybe it's not sensitive enough?

Maybe it's just a trick to make me stand underneath a powerline with one arm up in the air as people drive by wondering what I'm doing?

You can get electricity from your phone line without paying for it. I don't think it is illegal to do this. You just want to answer his questions anyway I'm guessing.

Some years back, a farmer who lived nearby put a large coil in his field near where the power company ran a high voltage line on a right-of-way. In other words, it was still his property down where the coil was. Suffice to say, he was charged and convicted of theft.

funny--power lines have a LOT of 'loss'---I wonder exactly if what he did 'pulled' power out of the lines, or was he just 'salvaging' the 'loss'?------and, IF he did pull 'some' power off (an additional loss of power in the 'lines'), I wonder, how proportional it was to what he 'got'?

If I had to make a guess, I would suppose he used (useful + waste) at least 95% of what the power line "experienced" as a result of his coil. Relatively long distance, large air core transformers work pretty well except that the regulation is just awful.

did you read this at the bottom of that page?:

http://www.sandman.com/telco.html

"Major toy manufacturers in China have agreed to install these Depleted Uranium Power Cells in toys for the next Christmas season, so parents will never again have to worry about buying batteries for their children's Christmas toys."

"Get the lead out of those toys, boys, we have something 'new' to stick in them!"

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russ_watters
Mentor
funny--power lines have a LOT of 'loss'---I wonder exactly if what he did 'pulled' power out of the lines, or was he just 'salvaging' the 'loss'?------and, IF he did pull 'some' power off (an additional loss of power in the 'lines'), I wonder, how proportional it was to what he 'got'?

russ_watters
Mentor
did you read this at the bottom of that page?:

http://www.sandman.com/telco.html

"Major toy manufacturers in China have agreed to install these Depleted Uranium Power Cells in toys for the next Christmas season, so parents will never again have to worry about buying batteries for their children's Christmas toys."

"Get the lead out of those toys, boys, we have something 'new' to stick in them!"
At first glance I thought that maybe the site was legit, but thinking about it, the phone line doesn't carry much current unless the phone is ringing, so it really isn't possible to harness it to power anything with any significant power usage.

The depleted uranium thing was the clincher. That's like saying you can get power from lead. It doesn't do anything. There is no such thing as a depleted uranium power cell. In fact, that's playing on one of the dumbest misconceptions people have about radioactivity: the longer the half life is, the less radioactive something is. So the fac that depleted uranium has a 4 billion year half life means that it isn't very radioactive. You could use it for a fishing weight and not worry about it.

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Some years back, a farmer who lived nearby put a large coil in his field near where the power company ran a high voltage line on a right-of-way. In other words, it was still his property down where the coil was. Suffice to say, he was charged and convicted of theft.

I heard this story many years ago and I wonder if it really happened. Do you know that it actually it happened?

Yes, I lived nearby. Although I must admit I only knew the story from the newspaper and neighbors. I never actually saw the coil.

Isn't it more 'induction' than 'load'?

A transformer, even a terribly leaky one, reflects the secondary power (phase and all) back to the primary and vectorially adds that to any core losses and Ohmic losses and magnetizing current. Induction is the process by which this happens; load is what the power company sees.

mgb_phys
Homework Helper
At first glance I thought that maybe the site was legit, but thinking about it, the phone line doesn't carry much current unless the phone is ringing, so it really isn't possible to harness it to power anything with any significant power usage.
I twigged at the line powered cell phone !

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The other thing I forgot to mention was that the farmer who did this was running 28V lights off it, so it didn't matter much if the voltage sagged with increased current.

I don't think there was/is any way on earth that the 'power company' could detect '28v' lights/drop in power when the lines run for 100's, if not 1000's of miles-----

----somebody turned him in

mgb_phys
Homework Helper
It wouldn't produce a drop of 28V in the transmission line - the drop would depend on the current flowing and the line resistance.
I suspect the power companies monitor line loses to check for failing insulators, shorts etc. It is easy to measure the current/voltage phase very accurately to monitor the transmission line's transmission line properties.

I could lay a coil out (what 20-30' below the line?) and NOT hook it up---you're saying that THAT would be detected?

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(I have noticed, however, that the ants that have there hills above my buried power line have 7 to 10 legs.)

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mgb_phys
Homework Helper
If you didn't connect it to a load then in theory it could be detected but in reality it is unlikely.
If you connected it to a load and pulled a couple of kW out of it, yes - they might come looking for why their transmission line had suddenly developed an inductive load.
If they would find you depends on how long the line is and how much they could be bothered looking.

You don't have to worry about the ants from buried powerlines - it's the giant sand worms that are dangerous.

I still say/guess that it wasn't 'detected'----someone turned him in, he talked/bragged about it and it got back to the power company, they saw it, etc.

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sand worms?------I thought it was the neighbor's dog that was digging those holes

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uh-oh!!!

---------DUNE

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