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Digital Power Line Gets Buried
vyzar writes "NOR.WEB Ltd, the joint venture between UK telco Norweb Telecom and Nortel Networks developing Digital Power Line technology, for carrying high-speed data over electricity supply lines, is being disbanded, and the technology dumped.
Norweb Telecoms say that the technology has been "proved", but the project was disbanded for financial reasons. The fact that the technology leaked high levels of radio frequency in frequecy bands used by the UK emergency services, military, and radio hams; and that it was fighting an uphill battle with the UK radio licensing authorities, did not appear to be mentioned in news reports. "
We're going to get sheets and sheets of "told you so" messages, some of which will carry the "powerlines as an antenna" analogy.
:)
Fair enough, it all went shed shaped, but you have to give them credit for looking beyond the end of their noses. Consider for a second the following bits of conventional wisdom:
* In a few years we may have computers that can perform tens of thousands of calculations, per second !!! (excited and drooling scientists circa 1960).
* Nuclear power will be too cheap to meter (other excited and drooling scientists circa 1960).
* A free operating system will never be as good as a proprietary one (drooling Microsoft executives circa 1995).
* Many millions of computers, worldwide, will all be connected to the same network.
So we have some vast understatements, some over simplifications and one blatantly incorrect. But in amongst this company "we think we can get half a dozen Mbit/s down power lines" isn't that an outrageous a claim.
And the prize, had they made it work? Dead telcos. 80% of their business anyway. A nearly immeasurably large quantity of income for the next god-knows-how-long.
Nice try. Back to shining lasers from one rooftop to the next.
Dave
I write a blog now, you should be afraid.
Looks like my mind goes into random fact mode when heavily deprived of sleep. (I'm literally having eye spasms here. Somebody save me and patch uulib/mmencode directly into SLiRP and pppd for me).
Anyway, undersea copper cables carry so little traffic relative to fiber that they're no longer used for data transmission--some scientists have been taking them over as a means for analyzing the earth's magnetic field. In other words, lets see what happens when we do nothing to them...we've come along way since when once of the first(*the first*?) transatlantic telegraph cables was literally burnt out when the scientist operator on one end was so obsessed with getting voice signals over a cable never intended for such that he jacked up the voltage higher, and higher, until boom...
Then again, maybe we haven't come that far *after* all...;-)
"Sir! Sir, our transmissions from the NSA are being interrupted by...my god, will somebody get that 16 year old out of that alt.binaries group? We'll be down for hours!"
Yours Exhaustingly,
Dan Kaminsky
DoxPara Research
http://www.doxpara.com
Once you pull the pin, Mr. Grenade is no longer your friend.
First of all, the power lines are not intended for data transfer. They are intended for power transfer. This means that:
Disturbances leak in at free will, and also they leak out (which means radio interference).
A TV, microwave oven or a welding unit generate lots and lots of disturbances, which goes out on the grid unfiltered (well, to the nearest transformer station anyway).
The line from the last transformer station (where the data is moved to/from a real data communications line) to the individual houses can be ten meters or 500 meters. There can be one household or thirty on the same line. This means that the conditions vary wildly from house to house, and it is very hard to create a transmitter/receiver that will work everywhere, since they are typically optimized for a fixed line condition.
These things, and several others, means that yes, you can communicate over the power lines, if you have a short line to the transformer, and if your neighbour doesn't turn on his TV, and if you don't care about airplanes dropping from the sky because you confused their tracking system, and so on.
There are a few test systems in use here in southern Sweden, just intended for reading the power meter remotely. These systems communicate with around 1200 bits/second, and use small packages (I think it was less than 40 bytes). Each packet is retransmitted up to four times. Even so, they have an average packet drop ratio of 40 - 100 percent. Yes, that's 100% corrupted packages.
My opinion about all this is: Keep power in power lines, data in data lines and phone calls in phone lines. That's what they were designed for.
This was an ongoing saga, first published by some famed media hackers, then confirmed by a handful of groups, then denied, exposed as a hoax, then confirmed again.
:-)
0 515.txt
If you read Need To Know now, you can track this saga as it pops its head up in various magazines at various times. Typical internet bizarness familiar to slashdotters, where a good story gets repeated by legitimate news outlets with no fact checking. I still haven't made up my mind on this one
http://www.ntk.net/index.cgi?back=archive98/now
the AC
Hemos is like...sci-fi fans;he thinks technology is cool, but he hasn't bothered to understand the science it's based on
So the technology didn't work out; big deal. Okay, so the companies lost a tonne of money on the project (probably), but these things'll happen. Not every technology works, and we should be grateful that companies are willing to risk things like this happening; this way lies progress.
Here in Sweden, it was demonstrated a year ago that it worked on a distance of a few 100 meters and that, due to inter channel interference, you only could have one transmitter per three phase power suplye to a house.
It's a nutty idea anyway to transfer a MHZ range signal through an unshielded power line. The power grid is designed to deal with 50/60Hz frequencies only ... Btw., the technology itself has been known for some time - the serbian army was rumored to run parts of it's military network (air defense in particular) through it's (highly redundant) powergrid. Thats partly the reason why the US used carbon bombs to disable the power grid for a few hours. Obviously a military network is not nearly as bandwidth-hungry as millions of households browsing /. ;)
--Coke
Get background info on the radio intereference aspects here .
Supposedly--mind you, I'm a city boy, so WTF do I know--large chunks of the cross country power grid are just unshielded solid cable. Why pay to insulate over those kind of distances, when you can just shove the cables up pretty high and hope nothing like a large-winged eagle will short your cables...
"KFE: The Official Dinner of BFE."
The point is, sometimes when you design to the minimum specification, things get burnt. Most power grids were designed for tossing out 60hz AC at the endpoints. Higher frequency artifacts were just never considered in the design specs. So basically we're left with an infrastructure that truly *is* universally available(power company goes *almost everywhere*, because private power is still expensive--this'll change), but we can't use these wires all over the place because of a failure in foresight.
The most powerful example of not seeing where things were going involves Sprint--as far as I've heard, which, again, probably ought to be verified, is that when they laid their thousands of miles of cable they only put in a few strands apiece. All the money was spent doing the truck roll...and barely anything on expandability for the future.
There's a lesson here. We all seem to thing where things are going. I think technologists need to start quantifying the degree of unsurity in technological prediction, so that companies like Sprint and Nortel can evaluate their decision makings on much large timespans.
Well, at least that's what I think.
Yours Truly,
Dan Kaminsky
DoxPara Research
http://www.doxpara.com
Once you pull the pin, Mr. Grenade is no longer your friend.
I'm somewhat disappointed. I hadn't heard anything about it lately, and was just thinking about it a couple of days ago for some reason. I thought that it would be a great way to distibute information all over the country. Kinda like X10 units, or the devices you plug into an outlet to use the household wiring as a large antenna. But obviously at a much higher scale.
What would it do to the power grid though? The power comapny has large capacitor banks to counter any inductance introduced by factories/neighborhoods. I guess it's not a capacitive or inductive signal, but I can't imagine that that kind of signal on the utility lines would be all that easy to isolate, and provide the clean sinewave required by some equipment. I guess since it isn't going to happen, these aren't major concerns anymore.
Baggio
Time flies like an arrow;
Time flies like an arrow;
Fruit flies like a bananna
Radiation from DSL, which uses balanced twisted pairs, much less likely to radiate, is still a problem. To think that this would work on poorly balanced, non-twisted power lines over long distances was a pipe dream.
Thanks
Bruce
P.S. My home alarm, phone, and data wiring is on shielded twisted pair.
Bruce Perens.
Most of the UK uses buried powerlines. As the DPL trials were in urban areas, and used substations as local hubs, the street-light flicker would have been induced at a distribution level. There were many security concerns as a result of this distribution model - and contention levels were higher than for alternate broadband techniques.
Interestingly, a friend in Bath builds HiFi components, and has discovered that one of the biggest sources of noise in his system is the daily DPL data dump from the local substation to the SWEB control centre in Bristol.
S.