Slashdot Mirror
Wireless Electricity Set to Power Village
freedommatters writes "The UK Sunday Times has a story today about how "Scientists have successfully applied the technology used in microwave ovens to beam electricity without the need for unsightly pylons and overhead cables." A prototype has illuminated a handful of light bulbs and they expect to be able to power a remote village within three years."
I can feel my brain warming already.
Honor Among Slackers. A veri
It's a cool technology but if it's implemented there would be even more radiation for our brains to absorb.
Dr. David Carpenter, Dean at the School of Public Health, State University of New York believes it is likely that up to 30% of all childhood cancers come from exposure to EMFs. The Environmental Protection Agency (EPA) warns "There is reason for concern" and advises prudent avoidance".
Now we just need this for laptops! ;-)
8==8 Bones 8==8
is obsolete.
I write code.
I wonder if there are risks of this? I mean, how long until their fish have 3 eyes, and children are born with 4 feet? :D
... oh well, as long as it's being tested on some small village and not me
and viola....
So there.
Didn't Tesla already do this? He was just dubbed insane and hounded while others stole his ideas. Case in point: Marconi
In the beginning they called it lightning, now they call it Wireless Electricity!
Note to self: get smarter troll to guard door.
I assume the microwave beam would have to be highly focused in order to work. What safegaurds are there to make sure nothing gets in the way of the beam?
(the article is unavailable without a $55 subscription, maybe it is spelled out in the article?)
If only he had more money to make it work.
We can all save millions on cooking costs by just putting our popcorn and leftovers outside for a few minutes!
Why can I never read the stories on slashdot unless I sign up for a service I would otherwise never use? On top of that, once they have your email address, they probably send some spam. Mmm... Spam...
We're only gonna die from our own arrogance, that's why we might as well take our time...
Warning: Don't look into the microwave beam with the remaining eye!
If you transmit a few kilowatts via Microwaves, just be careful not to walk into the microwave ray, unless you are well-shielded. Wrapping yourself in tinfoil should help. You don't want to end as a fried chicken, do you?
Sorry, this idea is DANGEROUS NONSENSE!
Denken hilft.
Is a similar concept. Radiation from the sun converted into electricity.
No need to microwave your AOL CDs anymore ...
Just take them out of the metal tin!
Does anyone recognise this story? I'm sure I've seen it before somewhere... Wireless Electricity Set to Power Village.
Let's call this one a dupe and then when it appears again we can all have a lovely discussion.
He "believes that it is likely." That doesn't mean he had any empirical evidence whatsoever.
Repeated controlled studies have shown that there is no connection between power lines and cancers except in the sense that neighborhoods near power lines tend to be of poorer people who have a higher incidence of cancer due to lifestyles (i.e., they smoke a lot).
Do I smell cancer?
Call me an alarmist, but I want to see the 50-year health studies before I go to something this, er, extreme. I mean, it could be completely harmless, but it just *seems* like something so potentially fraught with problems that my instinct is to avoid it.
Every year during my review, I just pray the words "slashdot.org" aren't mentioned.
Why aren't lines buried to be less obtrusive, better insulated, and non-problematic in ice storms?
Recently, in February, South Carolina, my home state, had a very bad ice storm. It was called "the worst on record". Why was it called that? It wasn't really the worst. Duke Power, our service provider, has failed to maintain the lines in there above ground condition. Lots of trees had grown through power even over and around some lines. Then there was the typical stupid driver who ran into a number of poles all over the area.
I was without power for 4 days. Luckily, I had an UPS unit from a server that has 40 hours and I use a laptop as my main computer. It powered everything in my place including a small heater for a while.
To be on topic, eventhough the above is too: I don't think we should be pushing conventional power to 3rd world countries. With this implementation of "beaming power" - power still has to be generated at a plant with with most likely a non renewable resource. Why can't we give these same people advanced windmills and solar cells? (Then teach them maintenance) That makes so much more sense. I see the costs of even an experiment; very high. Also, I think Microwaves at a ground level would interfere with radio communications at the points below the transmission.
Yell & scream & rant & rave... it's no use... you need a shaaaave ~ Bugs Bunny
Microwave power transmission always seemed like a slick idea until you try to control whatever line-of-sight airspace connects your transmitter and receiver. I would like to see this supersized in a satellite sending solar radiation down to earth-bound substations... but what about all the pretty birdies? Taste like chicken I guess...
Fnord.sig
Boardcast power is an interesting idea. I wonder how this solves the issue of power falling off with the square of the distance. Also, what is broadcast can be received, often unintentionally as interference. I can't say that I want to receive broadcast power on my radio, TV or fillings.
The net will not be what we demand, but what we make it. Build it well.
not only will the microwave power supplies provide wireless electricity, but also a supply of delicious fried pigeons.
But seriously, this wireless electricity must p*ss off those projects trying to provide internet connectivity via power lines...
So does Anonymous Coward have good karma?
Tesla was pushing "broadcast power". It was doomed to failure because of the problems inherent in charging the atmosphere. What they are proposing here is quite different. Haven't read the article, but I'm slightly familiar with the concept here. You simply convert electricity into microwave radiation and transmit it in a tight beam to a receiving station. No problem, old hat. Doing it on this scale might be a challenge, though. On the other end you have a receiver that converts that radiation back to usable electricity. Quite a different problem. I suspect that's what they're pioneering here. I think it has actually been done before, but not in any practical way. Powering a few lightbulbs isn't exactly practical either, but it would be if you could power a small town, or even just several buildings.
But keep out of the way of the beam!! I have to wonder about the environmental damage of birds/insects flying through it and getting cooked.
I remember reading about a proposal to send power to the earth this way. By having a massive solar cell array in space transmitting microwaves to a giant receiver on earth, you could gather lots of energy. The thought of this thing getting off track and aiming at, say, NYC seems a little too scary, though.
"Microwaves for the electricity are targeted via antennas and reflectors at a ?rectenna? (from the words rectifier and antenna), "
;-)
I'm glad they defined a rectenna for me...I thought it was an antenna you stuck up your ass!
-psy
we can have electricity over IP over 802.11b!
I tried to access the article on the Times site, was told to register, did so, was told to enter a "prize draw," did so (with false info), was told to pay for a subscription to the print edition, didn't do that.
Going through Lynx I managed to get to user login, and after logging in was greeted with a nearly blank page.
Anyone care to post the article, if they can even get to it?
The coolest voice ever.
This is a more detailed publication pdf file
Five, Four, Three, Two, One....
Well, I doubt this is really as dangerous as all that, but just made me think back to fond memories...
This technology has been powering my Sim City for years!
Instead of having plentiful places for birds to rest in urbanized areas, we get partially cooked ones occasionally falling from the sky! Allright, not really - but it would be oddly funny to see a bird or insect perch in one area up high, enjoying unexpected warmth, then suddenly move away due to sudden discomfort or unexpected smell.
I can't imagine that microwaves would end up anywhere near as efficient as wire transmission, but it is a nice idea for when you have a source of energy you otherwise couldn't capitalize on (like extra-planetory solar radiation in the recent Sim City games), and just want to siphon as much in a direction where you can't use more efficent methods.
Ryan Fenton
Does this remind anyone else of the start of the Japanese Imperial State in Shadowrun?
Damn, that was a cool game.
There are four boxes used in defense of liberty: soap, ballot, jury, ammo. Use in that order.
Electricity can be beamed through the air without a pylon in sight
Roger Dobson
SCIENTISTS have successfully applied the technology used in microwave ovens to beam electricity without the need for unsightly pylons and overhead cables.
The power is fired through the air in the form of microwaves and collected in special antennas that reconvert the microwaves into electricity.
A prototype of the wireless power technology has shown the system works and a full-scale version is now being built to make a remote village on the French-governed island of Réunion in the Indian Ocean the world's first microwave-powered community.
According to a report to be published this week, the system is a cheaper way than either solar energy or local generators of supplying remote areas not connected to a grid.
"(Electricity) network distribution is effective at the centre but the costs increase quickly when you get to the edge," said Dr Guy Pignolet of CNES, the French space agency, which has conducted the trials.
"Extending it to remote areas is very costly, but with microwave technology you do not have those costs. You also do not have pylons, which you may not want in sensitive areas."
The technology works by converting direct current (DC) electricity into microwave power at the transmitting end in the same way that switching on a microwave oven converts electricity into waves using a device called a magnetron. Residents are unlikely to be baked as the frequencies in the two applications are entirely different.
Microwaves for the electricity are targeted via antennas and reflectors at a "rectenna" (from the words rectifier and antenna), which absorbs the microwave energy from the beam and converts it back into DC power with diodes.
In Grand-Bassin on Réunion, which lies at the bottom of a 3,000ft canyon with no road access, electricity is currently provided by solar panels placed on the roofs of the houses. But increasing the amount of electricity solely by using the panels is difficult because of the amount of surface area needed. It is also expensive.
The researchers have successfully produced a field prototype to illuminate a handful of light bulbs. A second prototype is being finalised and will be in operation in about 10 months, while the whole project to supply the village with power is scheduled to be completed within three years.
Additional reporting: Nick Speed
A city-powering microwave plant that took electricity generated in space (the moon?) became avaliable in 2030. Perhaps the brains behind the game were not so far off with what seemed far fetched ideas.
Microwave power stations were great, until the beam lost its tracking slightly, sending it on a spectacular journey through your city.
The electricity receiver is dangerous. Do NOT try to dry yourself with it! neither any kittens!
It's a kind of neat trick. The receiving rectenna interacts with the transmitter(s) through the EM field to focus the beam on the receiver.
Inherent in this is that the rectenna needs to be quite spread out, so that the beam intensity on it is not high anyway.
As long as it's working, all is well. When it breaks... the beam, no longer focused, spreads out over a much larger area, reducing the power absorbed by the environment to a tolerable limit.
[100% ISO 646 Compliant]
SVM, ERGO MONSTRO.
But really, now that I think of it, I should have told them that it would have worked if they'd implemented RFC 3251 over 802.11! ;)
In Soviet Rush, today's Tom Sawyer gets high on you.
Nice to see the wheel re-invented, again.
---- Booth was a patriot ----
Quick, someone make an RFC for ethernet over wireless electricity!
to beam electricity without the need for unsightly pylons and overhead cables
all overhead cables have been removed from many european cities years ago. the secret? underground cables. yeah, i know it costs money but not having to worry about power outages in storms (never mind surges when lightning strikes nearby), having the wires and poles removed is sure worth it. no brain frying either.
Will we get roasted? We mostly manage to avoid existing pylons as they're visible. What about birds, for that matter
On the other hand, if these things heat the air, perhaps we can travel vast distances using the resulting linear thermals.
As a user of RF spectrum, all I can say is that is all we need.. one more source of RF pollution.
C'mon, Sim City has had this for years...
When I was in like fourth grade, I thought up an idea about wireless power. My friends and I schemed up a plan to use a wireless power distribution system to run automobiles. There would be a wireless power node at various points on the power lines in the city, and each one would direct power to cars nearby. The owner of the car would never have to gas the car up, and would just get a bill based on the amount of power his car drew. I even used the terms "microwave" and "electric car" even though this was like eight or nine years ago. I guess it just goes to show you, listen to your kids.
Lack of eloquence does not denote lack of intelligence, though they often coincide.
we could bea little bit more accurate.
It's wireless power transmission, yes.. not "wireless electricity". Wireless electricity is like, lightning, electric sparks, or electron beams....
This is microwave power transmission.
What we need is not another way to get energy from power plants to towns and houses but small clean power generators in every buiding.
Then again, the oil lobby blocked every innovation for cars, so this is not gonna happen soon.
(And that comment was NOT a flamebait, just my opinion)
It's not as dangerous as you might think.
First, if you assume the conversion from microwave back to electricity is very efficient, compared to say, solar power (the principle being the same, right? The photoelectric effect).
Now think of how much energy is in the noonday sun in, say, a 10 square meter area. That's quite a bit of energy.
Now, you could quadruple the energy density, and probably not kill anything that passed by. Sure, they would sunburn 4x faster, but.. in passing, it would be relatively safe.
Articles in the past have stated that it's much the same thing.... yes, it's a concentrated beam, but it's nothing like the energy density inside your microwave oven...
Imagine you, children playing with silver mirrors, terrorists shooting an objective with this experimental machine (the film "Eraser"), the machine did lose the calibration and did kill a lot of people on the town, ..
JCPM (copyright)
It could be safe if they used parabolic dishes or yagis or whatever. Since they're using the same frequencies as microwave ovens, and those use the same frequencies as 802.11b, they can use all the WLAN antenna shapes (albeit beefed up a bit) to make sure the waves get focused into a tight beam.
Then just put them up on tall towers with an accompanying radio link, so when the receiving station stops getting power, it sends a signal for the sending station to stop sending it. This will prevent havoc caused by beam misalignment - a small price to pay for a temporary brownout.
Though I'm still wondering whether it would be powerful enough to fry birds as they flew through the beam. Look, daddy! It's a bald eagle! (BOOM!)
Seriously, though. It could work.
Tesla would be proud, but baffled they weren't doing it his way. I still like the stories of Tesla scaring the shit out of his neighbors by creating simulated earthquakes and lightening storms for miles around... one of the few reasons I'd love to have visited the 1800's for a short while.
;-)
BTW folks - all microwaves aren't bad. Just the resonant frequencies of water molecules that are bad news. Filter those out and anything that might produce them by multiplication and life is pretty safe. Well at least it seems ok to me - I haven't fried underneath those microwave towers on the hills when we hike yet. (Yet
Why not just increase the electronic smog to microwave levels? We will all have to live in Faraday cages to be safe and travel underground to avoid exposure to the IONIZING radiation. Smells like the old beam microwaces to an array of detector diodes and use the resulting power for whatever... It has been tried before and rejected by normal thinking adults.
Well, the server appears to be down, but it a most Slashdot way, I'd like to comment on the article without even having read it!
Nikola Tesla himself was known for doing stuff like this . But I don't believe the 95% efficiency for a second...You can't even get that though wires if they are long enough.
Practically, "Wireless Electricity" already exists; it's called radio. The difference is only a very tiny current is induced in an antenna, whereas these folks in the article are trying to power a light bulb.
The biggest problem with trying to do this is that electromagnetic waves drop off very, very rapidly as they propagate through space, and to counter this you need a huge generator. If you had such a thing you'd need to direct beam it to this village and you can bet the stream would barbeque everything in its path. Also, radio waves are not lasers...It is very difficult to control where they go, so you could expect a certain spread as it propagated form the power source. I would bet that a lot of the people in the source, destination, and everything in between would be exposed to these amounts of insane EM radiation constantly, and that can't be good.
In short, my take on it is that while this has a certain coolness factor, it's way too impractical. If they don't want to mess with running wire, they should just construct a fuel cell generator and leave them with a hell of a lot of hydrogen. And they can do this now, not wait three years.
-R
That much power focused into a beam will probably be enough to boil water. It'll be interesting to see if this has any side-effects during a rain shower!
Maybe we'll have the 'beams of steam' going across the various valleys in France!
Electricity can be beamed through the air without a pylon in sight
Roger Dobson
SCIENTISTS have successfully applied the technology used in microwave ovens to beam electricity without the need for unsightly pylons and overhead cables.
The power is fired through the air in the form of microwaves and collected in special antennas that reconvert the microwaves into electricity.
A prototype of the wireless power technology has shown the system works and a full-scale version is now being built to make a remote village on the French-governed island of Réunion in the Indian Ocean the world's first microwave-powered community.
According to a report to be published this week, the system is a cheaper way than either solar energy or local generators of supplying remote areas not connected to a grid.
"(Electricity) network distribution is effective at the centre but the costs increase quickly when you get to the edge," said Dr Guy Pignolet of CNES, the French space agency, which has conducted the trials.
"Extending it to remote areas is very costly, but with microwave technology you do not have those costs. You also do not have pylons, which you may not want in sensitive areas."
The technology works by converting direct current (DC) electricity into microwave power at the transmitting end in the same way that switching on a microwave oven converts electricity into waves using a device called a magnetron. Residents are unlikely to be baked as the frequencies in the two applications are entirely different.
Microwaves for the electricity are targeted via antennas and reflectors at a "rectenna" (from the words rectifier and antenna), which absorbs the microwave energy from the beam and converts it back into DC power with diodes.
In Grand-Bassin on Réunion, which lies at the bottom of a 3,000ft canyon with no road access, electricity is currently provided by solar panels placed on the roofs of the houses. But increasing the amount of electricity solely by using the panels is difficult because of the amount of surface area needed. It is also expensive.
The researchers have successfully produced a field prototype to illuminate a handful of light bulbs. A second prototype is being finalised and will be in operation in about 10 months, while the whole project to supply the village with power is scheduled to be completed within three years.
Additional reporting: Nick Speed
"The life and times of Nikola Tesla" ISBN 1-55972-329-7
Read that, it has all the information you need, and documented sources.
I have also seen examples of his coils in real life creating the effect of 'wireless power transfer'. Its simple high frequency air-core transformer theory really.. its not complex in our age.. it was totally amazing in his..
Figures you would post under anonymous, cant hide behind facts.
---- Booth was a patriot ----
Tesla won the patent for radio because his plans included both a transmitter and receiver, while Marconi only had a transmitter. Transmit all you want but its worthless without a way to capture the transmissions.
Only the State obtains its revenue by coercion. - Murray Rothbard
Even though there are all sorts of disaster warnings, my city had microwave power for a good 50 years (until the power plant naturally self-destructed harmlessly) and not once did we ever have a mis-alignment. Perhaps if I set the disaster rate up though...
Seriously, I think the biggest issue would be to make a line-of-sight that would unlikely be crossed. Like mountain peak to peak. Convential cables can carry it along more dangerous paths.
- WrexSoul
\/.
vvv
... but one day, he was proven correct.
Nikola invented wireless energy. This is Not News, but it is a Good Thing©.
I suggest you read Slashdot
Hey, if it's good for the Sleestack it's good enough for us.
login with slashdot/slashdot
Then post.
This isn't a case of general broadcast, it's point to point.
They also claim that, since it's different frequencies, that they "won't bake the residents." Though I'm not sure about it, I'd think anybody who actually is in the middle of such a project and says such a thing probably know's what they're talking about. (Though obviously spectacular exceptions exist.)
In any case, if they start baking residents, passersby or wildlife, I assume lawsuits will fly. I also assume that somebody has consulted tech-aware lawyers already regarding this issue.
********* sig: If you don't like the law, get filthy stinking rich, and buy a better one.
The inverse square law isn't about power disappearing.. it's about energy density (if that's the right term) It just means if you measure the energy spread over a certain area at distance n, then the energy density over that same area at distance 2n will be 1/4 as much, and at 3n will be 1/9 as much.
So.. look at something like, a typical laser pen with a nicely columnated beam. Say at 1km the red dot is 1m^2 (just a guess).
Now, if we pretend it's a vacuum and we aren't losing energy due to reflection off particles and whatnot..
The energy density has gone way down... what used to take up less than 1 square mm now takes up 1 million square mm. (1 square m). Inverse square law at work.. but is it a problem for us to, say, build a receiver that's 1 square meter in size? Heck no.
i always thought the energy of an electromagnetic wave decreases with the cube of the distance...
The microwave beams from military radar on ships regularly cause sea gulls to explode. A megawatt beam will do in a bird pretty quickly. Power generation plants put out 100's of megawatts.
Microwave ovens work by heating water molecules. Broadcasting anything that heats water has a very high loss rate when it is humid. This is the reason satellite TV can die when it rains.
One possible use is in the desert to an isolated community. Perhaps it would also be possible to beam electricity to people on a mountain top. Very limited use technology.
Then there was Tesla's problem when he proposed to beam power to people 100 years ago: how do you get people to pay for the power they use?
Infrastructure is an evolutionary process. It's the fact that we have cheaply available power that sets up the conditions by which we produce cool power hungry gadgets. It's the fact that it can be delivered in large amperages to densely packed locations that makes it so everyone in your apartment building can watch a separate big-screen T.V. at the same time.
:)
Thus, it is completely unfair to knock this technology because it will never be a match for a burly copper cable.
Imagine what it's like to live in a remote village that has no power available. First off, this almost always means no phones, land-line or cell. It also usually means that the families that are better off run their generators during certain hours of the day, producing noise and fumes, and enough power to get some work done, but they don't run them day and night. Four hours a day at a few hundred watts of power and no phones would significantly change most of our lives.
The most important thing microwave power could provide would be to enable a low power cell-site to give continuous operation at low cost. Unobstructed, 10 five watt channels would provide good communication for a few thousand people if used frugally (the way everybody did when roaming was $2 per minute). The people in the town could set up cellular fixed station adapters and wire their homes with copper and have a cheap phone in every room. With rechargeable batteries that charging up during the generator "power hours" they could have hours worth of night of phone calls to everyone else in the village, and more importantly to people outside the village with which they might want to do business. Even people without generator access could buy a pocket phone with two batteries and leave one at the neighbor's house charging while the other stayed in their pocket to give them emergency contact capability.
In regularly overcast areas (I live in one) the day often has enough light to see by, but not enough to read by. Just one 30 halogen bulb produces better reading light than any oil lamp I've ever used. Without light to read by, or TV of course, nights around here could get pretty boring, and homework pretty hard to do.
Since this is "a remote village" that means it's likely there are some uninhabited outskirts between it and the nearest big city. So between your microwave distribution points there wouldn't have to be any people at all. They could also aim the beam such that overspill wasn't directed toward the town.
I don't like the idea of radiation burns any more than the next person, but if done correctly there would be little danger. This could be a tremendous asset to people living off the grid, and to tower-climbing children wanting to roast hot dogs.
Microwaves for the electricity are targeted via antennas and reflectors at a "rectenna" (from the words rectifier and antenna), which absorbs the microwave energy from the beam and converts it back into DC power with diodes. - so where do you put a rectenna exactly and how efficient is it at receiving electricity? Is it high voltage and/or currency? A high currency rectenna........ wait a moment!
You can't handle the truth.
Yes, we will be like the Protoss.
Kind of gives "don't cross the beam" a new meaning...
In order for this to work, they would have to make the beam extremely focused from transmitted to receiver.
If they don't do this, not only do they get the heatlh issues you point out, but the system simply won't work in practice.
All energy that is not captured by the receiver is lost.
Tor
Come on, people that work around microwave antennas do have higher incidences of cancers.
I am aware of cancer clusters around some high voltage power lines that was traced to chemical compounds (used in the insulators, IIRC), but no responsible studies that link microwave antennas to cancer. (I use the qualification "responsible" because I have seen "studies" by the cell-phones-are-killing-us wackos that make the claim, but their methods were so flawed it was funny.)
-- MarkusQ
What the hell is "the technology used in microwave ovens?!?" Buttons? Electricity? Light bulbs? Microwaves?? Do journalists even read their own inane statements? Hey, I just harnessed the technology used in keyboards to send an e-mail, it's revolutionary...
The first thing I thought about reading the headline was Normality, because at some point in this game (one of the funniest adventure games I've ever played) you had to use a big battery and a power transmitter/receiver to power something. That's why the story was a bit disappointing for me :7
Hell is not other people; it is yourself. - Ludwig Wittgenstein
By positioning the microwave beam across a migration route, the people in the village get roast duck for free.
RMN
~~~
1. If you blame a movie for something that happens then you must also blame your eyes. And after reading your statements I would guess that if there are people out there as stupid as you then there should be laws against people like you seeing movies and epecially owning guns.
2. You begin a statement of opinion with "In fact"
3. Alliyah died in a plane crash.
4. You are pathetic. I feel sorry for you.
This was the case all over the village (yes, it wasn't even a town.)
Whether a municipality is a town, village, city, etc. does not indicate the size. In many states, there is no legal difference between them.
My local power coop says that underground lines are LESS reliable than above ground. Sure tree can fall on above ground wires, but moles can chew through underground wires. The difference isn't big, but it is statisticly significant: there are more outages in underground wires than above ground.
The arguement for underground is looks. People don't like looking at power poles. (personally I think a power pole running through the yard is less intrusive than the big transformers they put in front of a hosue with underground wires, but most people disagree.)
This cant be healthy...
Also, how does this work for non fixed point to point? Can we start on that last run of de-wiring, removing that last sinful vestage of the computing world, the power source? Kiss your four hour battery lives goodbye?
Myren
Not only can it Power a small village, but also provide food in the form of small fried birds falling from the sky! Won't rain water interfere with it?
Didn't anyone here play Simcity 2000? The microwave power plants were solar satelites that gathered solar energy and transmitted it down to the power stations. Of course one of the disasters of the game was when the beam missed the ground station and half your city burst into flames. Fortunatly we can just disable disasters ... ert, wait ...
Does anybody remember the microwave energy plant in Simcity 2000 and when the microwaves became dealigned wreaking havok on neighboring buildings? What if that happened here, random microwavings, a new hazard to living.
Checking out my form of escapism.
That old power line thing was disputed a while ago - mostly just a media fad. I was working at the NIH with one of the guys who first noticed the magnetic field effect on celles in culture.
It has never been shown to cause any cancers.
Radiat Res 2000 May;153(5 Pt 2):627-36 Related Articles,
Leukemia and lymphoma incidence in rodents exposed to low-frequency magnetic fields.
Boorman GA, Rafferty CN, Ward JM, Sills RC.
The PCB coolants used in/around many of those power stations is another subject.
Just to help hammer the nail home, there are many FDA approved devices that use magnetic or pulsed elctronic field devices to aid in bone healing. No reports of cancer yet in these either. Some increased cell growth yes, but cancer no.
This kinda crap science is usually perpetuated by the media and lawyers hoping to make a few bucks (well, usually they want a few million).
Bah!
..........FULL STOP.
Any beam of electromagnetic radiation will spread out a little bit due to diffraction. This is a bigger problem will microwaves than, say, laser beams because longer wavelengths result in greater diffraction.
Also, the receiving antenna will re-radiate a certain amount of energy. It would be physically impossible to avoid at least some human exposure to microwaves in the vicinity of this project.
The microwave systems that SSI have studied are basically like a UHF tv station transmitter (sans Weird Al).
Birds don't cook, people don't mutate, airplanes won't crash from this. Since this is a line of sight system, the range is probably less than 20 miles. Even so, it will make a terrific demo that proves the practicality of powering cities from SPS.
Actually, in the Sierra-marketed game Outpost 2, this is exactly how they transmit power.
Another Sci-Fi wish come true?
We aren't certain about the effects of EMF exposure, so we are going to find some poor village without electricity and offer them electricity through microwaves. The expirement can pay for itself through the utility fees we charge the villagers.
Boy, did I wake up cranky today . . .
Sdelat' Ameriku velikoy Snova!
That is, depending on the power density of the beam, it may actually be capable of cooking birds in flight. Seriously.
The radars on some US Navy ships can put out enough power along a single line of bearing to damage aircraft electrical systems at a range of a couple miles. Microwaves are a byproduct of radar research, when it was discovered that radio waves of a particular high frequency were strongly absorbed by water molecules, causing them to heat up very rapidly. So a microwave beam of sufficient power to light a small town could legitimately pose a hazard to birds and other animals.
If they don't want unsightly powerlines, why not just bury the things underground?
Yes, there is good reason to believe that this "won't bake the residents." Microwave ovens emit microwave radiation at a frequency that causes water molecules to resonate. The radiation causes vibration, which builds up thermal energy. Being over 3/4 water, you would also be cooked in a microwave. A piece of paper, however, would not be heated nearly as much, since it contains no water.
The resonance effect is the reason that there are separate settings for "defrost" and for "cook." The frequency needed to match ice is somewhat different from that for water. I think that the frequencies are fairly close, so using the wrong setting works, just not quite as well.
For more information, check out howstuffworks or something like that. It's all pretty basic.
A smallish house in Canada (we are big, per capita users) is
on the order of 1000 ft^2 (or about 100 m^2), and might have 100 amp service. So, assuming a power factor of 1, our
energy demands are about 120 W/m^2, or about 1/4 of insolation value. If we had 25% efficient solar cells (or similar), we might be able to power an ordinary house by visible light. Latitude, house insulation, appliance efficiency all change the exact values, but this is order of magnitude stuff.
Some people are looking at generating power in space (my knowledge is to have the generators on the moon), and beam it back is microwave (same technology as shuttle side-scan radar). To get microwaves to sites on the far side of Earth, we have satellites which can reflect the power. The numbers are feasible.
I really don't think anybody stumbled across the fact that some wavelengths of microwaves can be used for cooking. People looked at the absorbtion coefficient as a function of wavelength. And behold, certain wavelengths are strongly absorbed by O-H bonds, like in water and fat. So, we sell microwave ovens that radiate there.
120 W/m^2: lets say we have water 1cm thick on that 1 m^2
surface. So, we have 10 kg of water. 120 W is about 30 calories per second. 10,000 grams of water getting 30 calories of heat (assume 100% absorbtion) is 0.003 degrees K per second heating rate.
Besides wondering what marketing genius came up with that name, just what kind of efficiency can you get with this principle. The losses are at:
a) conversion from AC to DC
b) conversion for transmission
c) losses due to Tx antenna efficiency
d) losses during transmission incl. energy lost toasting birds and folk getting in the way of the Tx beam
e) losses due to Rx antenna efficiency
f) losses during rectification to DC
g) losses during conversion to work (here light), more if you go to storage (battery) and back again.
Those add up pretty darn quick. Plus power received varies as an inverse square law of the distance from the transmitting site. Not very efficient. Seems like strictly a niche application.
"Consensus" in science is _always_ a political construct.
Hot Babes ! Can't wait...
You avoid the "children born with 4 feet" problem by aiming the beams and staying away from them. The main hazards are for people who want to eat the free microwaved chicken that collects under the beams, unless they retrieve it with a long stick or something.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
But isn't it a little bit early?
I'm the guy with the unpopular opinion
just follow the trail of cooked-in-flight wildbirds on the ground.
Maxis really should have slapped a patent on this idea when they thought it up for SSim City 2000...
Beep beep.
How Microwave Ovens Work
Yes, Tesla did suggest this. Stand near a tesla coil with a flourescent light bulb and it will light up with no physical connection. The reason we have wires is so that power could become a profitable industry. They had to have a way to meter the electricity that people were using.
I mean, gosh, imagine if people could just log onto the internet without wires. er...
Often in Error, Never in Doubt.
how long before we have people building their own recievers and taking electricity directed at other people's homes?
Guess who invented this technique? Nikola Tesla. These scientists may have built a system to use this, but they aren't the first ones. Read for yourself.
These incompetent engineers, don't they remember what happened when a stray beam hit your marina?
"Kids, how many times do we have to say this, watch out for the invisible power lines."
Efficiencies of over 60% have been shown in DC-DC transmission of power (look up microwave power beaming in google some time). Your "a" and "f" are the same issue, and the "rectenna" also adds "e" into the same process, so whatever loss there is in "rectennafying" it's one step. I've read 90+% is possible there; don't know if it's ever been done in practice. Your "g" is there no matter what you do with the power at the end, so that's a wash. "d" one hopes will be kept low - in any case, losses with traditional power lines are often 50% or more...
So that basically leaves "b", "c", and your final comment on the inverse square law as problems. The first two of these are a question of conversion efficiency which somewhat favors low frequencies. The inverse-square law problem is basically an antenna-focusing issue: obviously you want a high-gain antenna on the transmitting end, and a "rectenna" on the receiving end that is big enough to catch the main lobe of radiated power. Diffraction limits impose a minimum size on the two antennas; to keep those sizes down for a given transmission distance, you end up favoring high frequencies. The balance between antenna size and component efficiencies favors different configurations depending on total power, distance, etc, but end-to-end efficiencies of at least 60% have been proven, and 90+% is thought to be theoretically possible.
I believe the origin of this idea is Glaser's 1960's proposal for solar power satellites, which would beam power to earth via microwaves in the same manner. Not sure if Glaser used the term "rectenna", but O'Neill certainly did in "The High Frontier".
Energy: time to change the picture.
> But is it a problem for us to, say, build a
> receiver that's 1 square meter in size? Heck no.
No, it is not, but it will not get you pretty far either.
The average Laser pointer works at 630..670nm, while Microwave at, say, 1GHz has a wavelength of 30cm = 3*10^8 nm.
This is a difference of approximately half a million, and you will have to increase the *emitter* size (lens of 2mm in your laser pointer) by roughly that amount to get a focus at the receiving end comparable to the laser pointer's - i.e use a 1km diameter emitter dish !
Now of course it would be more economical to use emitters and receivers of equal size, but I would estimate that you would have to make both of them app. 20m in diameter to get 85% of the emitted energy at 1GHz from the emitter to the receiver if you are considering only the wavelength limitations.
You could use higher frequencies, but then the electrical loss in the transmitter and receiver would probably increase.
Microwave power transmission has been used before. Some tv companies use it to send power from base stations (saw a van) to remote feeds (say a camera crew up on a hill). That having been said I've never heard of anyone running something the size of a village before.
We don't need any oil,
Nor a Tokamack coil,
Solar power supplies Earth with juice,
Microwaves are sublime,
So no one will mind,
If we cook an occasional Goose
SimCity 2000!!! lol
:-)
Microwave power plants.
Watch out for those stray beams!
Hmm, then how about sending water through a pipe and running a turbine at the other end. Way safer, and you get the drinking water delivered too...
Tesla set up a huge Tesla coil and hooked it up to a substation. He turned it on and every light in the town lit up for about 10 seconds, then the substation burned out! The problem is that over the air transmission of energy is woefully inefficent. Look at UHF television for example: Many stations send out 5 MEGAWATTS of UHF energy to put microvolts of EMF into TV sets but a few miles away. In order for this to work, you'd need the RF equivalent of a plasma beam goig to each location....and I sure wouldn't want to be in its vicinity!
Hey, looks like Will Smith of Maxis was right. Microwave Power was available after 2020 in Simcity 2000.
Of course, does it also miss sometimes and cause a massive line of fire straight down the middle of your city?
-Ryan
AUWYHSTOT (Acronyms are Useless When You Have to Spell Them Out Too)
Assuming you could get 10 MW or so at 90% efficiency, you then have all the other steps to consider. You mentioned that the rectennas are able to convert 90% of the RF back to DC. I'd like to see the journal article. That sounds pretty amazing if it is true. But even if it is true, if you only take the Rectenna and magnetron into consideration, your efficiency is no where near 90%.
Then we move to the idea that you're beaming large amounts of 2.45 GHz radiation. Maybe the mW radiating from your phone and 802.11b router aren't a lot, but the quantities needed to generate DC power can cook a turkey. I wouldn't want to be the turkey anywhere near the path of that beam. I don't care how well it is aimed to a collecting rectenna.
http://www.ac-grenoble.fr/yre/agency/library/missi ons/missrep1997/online/rap-nuc1.htm
Tesla's idea was charging the earth itself so that all you had to do was plug your gadget into the ground to get power. funny stories about people getting 'grounded' around his home town late in his life when he was performing his experiments.
I think he also noodled with an atmospheric version where you bounced energy at specific frequencies off the ionozphere for over the horizon power beaming similar to the way shortwave radio works. Actually other than the insane amounts of power needed to usufully retrive it you could simply broadcast more energy in the radio badwidths and recover it.. after all thats technically what your doing when you listen to a radio. Would be an intresting experiment to see how large an antenna you would need to power a small light with ambient radio waves. Since that is radiant non focused energy that whole decreases by the square of the distance etc.. would apply. I supose Tesla had some theory for a way to focus the beam for a means of usefull energy delivery levels but its been a while since I looked at his stuff.
I don't ask you to be me. I only ask you not expect me to be you.
If you played Simcity 2000.
Microwave power plants were an expensive, moderately dangerous power plant (Missed beam, anyone?)
I never really was a fan, but I did wonder if such a thing was scientifically valid. Guess it was.
Begun, this browser war has.
The possibilities are both endless and quite frightening...
Ooooh, scary. And visible light (being of a much shorter wavelength than microwaves measured in centimetres) has a frequency that's orders of magnitude higher. Let's all hide in the dark!
In case you missed the sarcasm, microwaves don't cause the sort of cellular damage that UV, X-Rays, gamma rays cause (with gamma rays being the most energetic/damaging). Microwaves aren't ionizing radiation, they just make molecules rotate around a bit more, ie. heating them. These microwaves may pose a problem if they heat objects that get in the way, though. It also depends on the wavelength of the microwaves - absorption by water spikes at 3 cm, but microwave ovens use a longer wavelength to penetrate deeper, since if it doesn't interact it can still get reflected around the inside until it does. Presumably, a wavelength used to transmit power would be chosen to be as inefficient as possible in imparting energy to water (and things that contain it, like brains).
I don't know who's more clueless, the poster or the moderators.
My guess is that its you...
I swear the quickest way to spot a conspiracy theorist moron on slashdot is to look for a post saying essentially that 'no it wasn't unfeasible schemes due to the laws of physics, it was the power companies and the MAN who kept him down!!' or some such.
Yawn.
The guy was experimenting with his own money and no one would fund his research. Not because he was a crackpot (you don't get a unit named after you when you're nothing more than a crackpot), but because there was no more money to be made with his plan than with the existing system.
So, in your "special" world view, there are no rich people protecting the status quo I gather? There is no such thing as big companies using monopolistic anti-trust tactics to protect their mind-boggingly large incomes? You must be right; Only a "moron" can believe that people would be willing to refrain from financing research that would undermine their revenue...
You would have to generate unbelieveably intense EM fields at the transmission station just to light a light bulb a mile away!
That was the plan.
By the way your other non-sequitor comment about the "Tunduska" (sic. Tunguska) event belies your ignorance as well, everyone knows by now that it almost certainly was either a comet or asteroid.
Bwahahaha, ah man, what a funny troll! : )
Yeah, everyone knows it was "almost certainly" a comet...or maybe an asteroid. What an incredible certainty! Truely you are the one and only holder of the One And Only Truth!
I especially like how you assume that I've never heard of the asteroid/comet hypothesis.
Of course, the fact that it was maybe a joke never crossed your little mind...you were too busy concentrating on your task of propagating the "everyone knows" gospel.
You can't take the sky from me...
How Microwaves Work
1) Microwaves only have a heating effect because they're emitted at the resonant frequency of water molecules. Try cooking a ceramic plate in a microwave: it won't heat up much, if at all. Just pick a different microwave frequency, and you avoid all the problems of cooking birds in the sky and whatnot (even if the energy density were probably too low).
2) To the guy who thought that mentioning the technology used in microwave ovens was stupid: the technology used in microwave ovens is not as trivial as simply calling them "microwaves". The physics of generating a microwave beam are significantly different from regular radio waves. They mention later in the article that they make use of a magnetron, which was the invention which made high power microwave generation really feasible. It lead to radar and all that jazz.
3) I saw one person mention this elsewhere. However, I'll reiterate: the inverse square law applies to the density of energy at a given distance. The energy does not simply "disappear" (this would violate something called energy conservation, meatheads). Build a big enough collector, and you can receive all the energy (with the caveats that it gets absorbed by the atmosphere, circuitry, etc.). In space, this idea would work perfectly.
4) Finally, this isn't exactly a new idea. People have been bouncing it around as a method for beaming solar power down from orbital satellites for ages and ages. (Also, the microwave power plant--and disaster--appeared first in SimCity 2000, not SimCity 3000.) However, as another poster noted, the innovation here (if there is any) may be in the amount of power transmitted, or practical demonstration of something we already know is possible from the physical equations (but perhaps nobody was lame enough to think it actually had a practical application right now--villages, really).
All in all, I'm disappointed that the overwhelming number of responses here have been of the 'they can't do that/that's impossible/it's too dangerous' sort. Talk about a bunch of technophobes. Apparently, a technology is only cool and grokable if it involves microprocessors. Anything else is scary physics stuff. Lamers.
By the way: laser pointers don't need lenses to shoot really narrow beams. That's because they're lasers. Lenses help, because the lasers you find in your average pointer are kinda crummy in that department--but they're not required. Thus, trying to compare the size of a lens needed to collimate a laser pointer to that needed to focus a microwave energy beam is ridiculous.
One last thing: microwave beams have already been used for microwave communication, so the idea of deploying all these microwave towers isn't such a radical idea. What do you think MCI stands for?
The cellular companies told us so... Why worry?
-- Leeeter than leet
Except in the sunniest areas with relatively low population density, solar power isn't going to cut it. So power distribution is the key, whether it's by wires (electricity), pipes (gas), trucks (oil, hydrogen, batteries), or the air (microwaves?).
Your "small clean power generators" idea requires fuel, and that fuel has to be distributed somehow. It seems to me that dedicated wires or pipes is bound to be more efficient than a fleet of trucks.
What's wrong with your statement is not so much about whether microwaves are harmful (I don't think they are, at least compared to many other hazards), it's the general attitude.
Many people have a problem with an attitude that puts more weight on facts than on dogma or unsupported statements. That's why faith based belief systems are so much more popular than doubt based belief systems.
Fear of the unknown is one of the big stumbling blocks. You are correct, microwaves could cause cancer. They could also cause terrorist atacks. They could reduce my grades, or make my ice cream taste funny. They could attract evil creatures from the planet Dacron, or they could give me super powers. It might seem that I would be safer if I didn't do anything with microwaves, or power lines, or cell phones, or trains that move over 35 MPH, or foreigners, or anything else until I make sure that none of these bad things I've heard are true.
But in fact, if I tried to live that way, I would quickly starve to death. So instead, I have this attitude that I am open to hearing about things (even things that directly contradict my deepest beliefs) but I don't accept them until there is a plausible reason to do so.
-- MarkusQ P.S. By "plausible reason" one of the things I mean is a reason that does not involve the magnitude of the consequences. Saying "if frogs rise up and eat all mammals every hundred years, it would be very bad" is not a plausible reason for believing that frogs do in fact do that.
--they have a microwave beam weapon that is deployable now. The military and the cops have it, supposedly it is "non" lethal. It only "Heats the skin temporarily to the temperature of a turned on incandescent light bulb".
6 au tumn/stanton.htm
Uh huh, like they don't got a "well done" setting on them bad boys.
As far as I can figure out,they are for the next series of mass riots in the states. There is also a bit of anecdotal I have seen on the web about a prototype being used in gulf war one, I don't have a link but I've seen the pics of dead guys all burnt up while their clothes remain relatively un scorched.
Here's a really old url from an actual military domain
http://carlisle-www.army.mil/usawc/Parameters/9
google has a lot more using microwave, nonlethal, riot
This sounds so indicitive of experiments Nikola Tesla was working on. Why is science in it's nature so slow to release what was probably known a long time ago. I guess we as pple are not ready for the knowledge?. Bah crap. Ohh well look up Nikola Tesla some time might make for interesting reading if you into the world of electricity and science.
Hmmmmmm,
I wonder if CmdrTaco meant "BODY Parts". Oh well, it's funny either way.
Actually, as I recall, Marconi was in violation of 14 of Tesla's patents for radio transmission when he made his historic broadcast.
Hardware, software, and blinking lights!
I would much rather be working around a powerline carrying 66,000V at dozens of amps than spend any amount of time near a small gamma source. The VLF (very low frequency) band won't ionize me and cause cancer (although it might cause eddy currents which could resonante and cause small amounts of higher-energy radiation...). The gamma source can cause cancer or even radiation poisioning from prolonged contact.
Hardware, software, and blinking lights!
(i mean... he invented encrypted wireless networking (the RC submarine, if you're curious)).
Hardware, software, and blinking lights!
So if a bird fly across the beam - the microwave signal will instantly roast the bird?
I guess he's right.....the radio wave version is a Maser.
The biggest problem I could see is that all the air in between would deflect the beam....
Solution: put up the equivalent of fiber-optics.
Ie., masers. Your oven actually contains the microwave equivalent of a laser. The beam gets bounced all over the place inside the oven, so you get more-or-less even heating...if you were to remove the maser, you'd have a modest beam weapon, though you'd need a hefty commercial model to do much damage with it. (But...don't try this at home! Microwaves reflect like crazy, and you're quite likely to hurt yourself if you don't know what you're doing.)
will the people glow too?
http://www.themercury.news.com.au/common/story_pa
Looks like some people are geting a jump start on the technology.
" FIRE authorities said today a Perth man was lucky to escape unharmed after his explosive attempt to recharge his mobile phone battery - in a microwave oven. Firefighters were called to the man's home in suburban Scarborough last night after the battery exploded inside the oven, causing smoke to pour out of the appliance."
so when you meet a girl and say "I can feel the electricity in the air" you won't just be saying that to get her in bed.
I guess this is the last we'll hear from you, then. There is a lot more electromagnetic radiation bathing you than microwaves would bother you. You've got a nuclear particle accelerator aimed at your head inside that CRT (let's hope the X-Ray diverter is working). There is megahertz-level electromagnetic radiation leaking from that computer very close to you, and even worse if you ever run it without the case being perfectly sealed -- if your CPU is running over 1,000 MHz then you're up in the microwave range. And there are pulses of electricity bathing your fingers from the circuitry inside that keyboard, with your fingers being extremely close to them.
Gee, this stuff has been around for a long time. Didn't anyone do a search for "rectenna"? Or look up "The High Frontier" or any orbital power satellite proposal. They've been around since 1970s, and pictures of wireless power tests with them.
I am a communications systems / signal processing engineer, read: I design microwave system. To me, someone who stands to gain a lot from things like this, I can say I expect cancer and other health issues to skyrocket in areas that do this. This is *not* safe, not at all. Microwaves effect the way you brain functions, and not just because they will excite water molecules (which is how they cook - they essentially boil everything). The power you'd need for this just wouldn't be safe.
Still, if you can make a buck doing it, it will happen. Mobile phones aren't safe, we all know it and they're not that different from this, just a lot lower power. Some mobiles can still pump out 20W of microwave power - That's a lot to stick right next to your head.
Anyway, I KNOW all this, and I still have a Mobile phone on the desk right now, and I never go anywhere without it.
Bar the inverse square law problem that many people have already drawn attention to, there's also a minefield of trouble in the fact this is a line of sight transmission system.
Let's face it, the transmitter and reciever are going to have to be perfectly aligned for the power to be relayed with any kind of efficiency. What happens when the ambient temperatures at either end change? Thermal expansion of the transmission / reception tower. Over large distances, the fraction of a degree change this will cause in the target point for the beam with probably be signifigant. Not an insurmountable problem, but it all adds to the cost of such a system.
What about changes in weather conditions? While I doubt a rain or hail storm in the path of the beam will interupt it, I suspect the presence of the matter will cause some energy loss. Given the accuracy of Murphy's Laws, you can bet that loss will occur just when that energy is most needed.
Finally, has no-one else noted how much less secure this is as a method of power transmission? Rather than breaking into the local electicity substation, an enterprising young vandal could cut a community's power simply by sticking a correctly sized piece of shielding on a dirty great stick.
This is still electricity from a non-renewable power source unless the power they're beaming is itself generated from a renewable source.
Surely the receiving equipment is going to be just as expensive and real estate-consuming as a solar panel back or windfarm - why not just build one of those at the remote villages and do away with R&D costs and the hazards of things getting in the way?
Oh well, at least it'll make it easier to tap in without paying for it:
1. Obtain frying pan and foodstuffs
2. Hold in front of power receiving dish
3. ???
4. Profit!
coldcity
code, life, art
Microwave ovens operate at about 2.45 GHz, at which the water in food absorbs the energy well.
wavelength=c/freq c=3x10^8 m/s so wavelength~=122mm
If i remember correctly the rule of thumb for having holes in a surface and it still being reflective to that wavelength is that the holes shouldn't be bigger than 1/20th the wavelegth. So, so long as the wholes in the microwave cover aren't bigger than ~122/20=6mm you should be ok
On mine they're about 5mm which fits nicely. The fact that surfaces with holes in reflect as well as solid ones is also used in satalite dishes and radiotelescopes and probably other things
My spelling isn't bad, I'm evolving the language
2.45GHz, that's about the frequency of my wireless lan.. uh-oh..
Before you go providing 'easy' solutions, and talk about how simple it is, you have to actually have testing to backup your claims. There's this little place called NIST (National Instititutes of Standards and Technology) that actually tries to prove their theories before telling everyone how great of a solution it is.
You've never seen how much power there is behind a backhoe, have you? (and in correlation, just how much damage it can do). First, we have to consider that concrete is brittle in tension. (according to the BOCA code (sorry, I got out of civil engineering before the ICC formed), for concrete construction, you assume that the concrete takes no load in tension. You also assume, in the case of shear, that the concrete fails as a diagonal break, and can't hold up under the tension along the break... so, you'd have to allocate enough coating to provide for say, 17,000 pounds of force... and when you consider there's typically a 30 year life cycle for public works projects, the rate of increase in the power of backhoes over that period. [or, even better, you'd want to use LRFD to find the acceptable failure incidence so you don't go overdesigning everything and wasting money, as there is a point when overdesign wastes money, and you want to maximize your ROI (Return on Investment)
Now let's look at your 'road' example...
- If you build a larger road, will there be more capacity? (yes)
- If there's more capacity, will more people opt to use public transportation? (no)
- If there's more capacity, will there be an easier commute? (for a while)
- If there's more capacity, will it spur greater development? (yes)
- If there's more development, will there be more people on the roads? (yes)
- If there's more people on the roads, will we need more capacity? (yes)
- If we spend more money on this one project now, can we meet the rest of our goals? (maybe)
- If we overbuild on every project, can we stay within our budget? (not unless you want to give us more money)
- If there's more development, will we need to increase other infrastructure (schools, police, fire, etc)? (yes)
It's easy to quote just the facts and figures that you want to, especially when you lack any imperical data to back you up. Of course, even with statistics, it's easy to come up with numbers that support your arguments -- 85% of traffic isn't work related, so I heard on the news two weeks ago... But how is that number determined? (man-hours, man-miles, car-hours, car-miles). What was the region they looked at? How did they perform their sampling?Yes, sometimes, there are easy solutions... And many times, what's believed to be easy, isn', and just as many times, what's believed to be a solution, isn't.
Build it, and they will come^Hplain.
Okay, you're quoting some hokey new-agey alien-abduction source. I get it.
But I seem to remember something about mitigating the effect via sleeping in a pyramid.
Sounds like, "the popcorn got burned," to me.
Potentials were broken? Processes were transferred into the blood? I had no idea that microwaves could damage abstract ideas!
I can't take it any more...
Well, it depends on if the fields are strong enough to cause dielectric breakdown (arcing!) in whatever they're passing through.
For example, the dielectric strength of an insulator is the limit of electric field intensity that can be placed across it without stripping electrons from their atoms (ionizing the material) and causing arcing (reduction of the electric field via relocation of charge).
The main limit on the power handling capacity of waveguide is the dielectric strength of the filler (usually air). Forcing more power than the rated capacity leads to internal arcing and guide damage.
Your prescription that we should consider new technology to be harmless until there are studies that prove the opposite is dogmatic and, by definition, based on the absence of evidence.
I did not say that a new technology should be considered harmless until there are studies that prove the opposite. In fact, I gave an example (swimming in benzine) where I would be willing to accept that it was hazerdous in the absence of any studies.
You bet it is, and it isn't enough of a stumbling block: many new products and compounds are being released with no safety testing.
Mostly because it makes more sense to focus the limited time we have to test things on those that are more likely to be dangerous.
Again, what's wrong is not your statement that microwaves are harmless,
Again, what is wrong is your failure to read. I never said that microwaves are harmless. What I did was ask the original poster where they saw the tests showing that they caused cancer, because I hadn't seen it. And, I might add, dispite all the people attacking me, I still haven't.
-- MarkusQ
I asked for a responsible source. Not a bunch of pseudo-jargon babble.
-- MarkusQ
... or that "Slashdot is dying" thing will make a comeback.
... I've been looking for something freaky to fall back on whenever I hit on a chick in SF's Upper Haight.
Tesla planned to do it 100 years ago! The "Modern" world has just caught up.
Royski
The first 90+% was just the "rectenna" side of things (which was what the first comment asked) - overall system throughput would likely be at the 60% level or so. But that's not bad for a long distance power transmission system.
As far as published journal articles on this, here's a link to an HTML version of an article "BEAMED MICROWAVE POWER TRANSMISSION AND ITS APPLICATION TO SPACE" published in IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. 40, NO. 6, JUNE 1992, which covers the efficiency question in some detail, and a lot of other information besides. Worth reading...
Energy: time to change the picture.
I share many of your concerns with our present situation. However, I feel that you are being led off on into a huge maze of false trails by your lack of scientific thinking. Yes, corporations lie, as do politicians. And yes, they do so to further their own interests. But that doesn't mean it is safe to assume that everything said by someone in power or authority is automatically false; if you do so, you can be mislead as easily as if you unquestioningly accepted everything they said as true.
Learn some chemistry; not from popularizations, but from text books. Leran some physics, and some math, an above all try to get the nack of the scientific / sceptical mindset.
You can still work to expose what we both agree is bad, but you will be able to choose your targets much more effectively.
-- MarkusQ