Slashdot Mirror
Broadband Over Power Lines in Canada
Patchw0rk F0g writes "From Europe, we jump to la belle province of Quebec for the latest test of broadband internet over power lines (Real Player stream available.) Seems the utility is already utilizing the system to control traffic lights and such, and is exploring the possibilities of offering a cheaper service to consumers to compete with DSL/cable/satellite. Lower prices? I'm all for it... but I live in TORONTO!"
Swedish company Sydkraft also offers the service.
Sydkraft announced a copule of years ago that they would provide Internet over power line. Except for a small pilot project nothing ever happened.
The reality is that PLC might be technically possible, but the cost of deployment is much higher than compeeting technologies such as: ADSL, Cable Internet and Wireless Local Loop (WLL).
It seams that power companies like to run trials to test the technology, and make unrealistic press releases.
Bandwidth has nothing to do with the current through a line (or not much....)
A normal power line has been designed for 50hz (or 60hz) AC. A coax cable was designed for frequencies in the Mhz to Ghz range. A telephone line was designed for atleast several Khz (speach).
The dampening of a power line will be far greater than a coax cable.
The same is for shielding. A power line is very suceptable for interference from the outside and can radiate itself far more. That is why greater bandwidth (higher frequencies) will be a huge problem on these lines.
Simply put: They weren't designed for this.
Jeroen
Secure messaging: http://quickmsg.vreeken.net/
But it's to be expected, as they have the most advanced powerlines going. Remember that little blackout y'all had last Summer? As soon as the loss of power hit the Quebec border the chain reaction was stopped cold by the connections to the Quebec system. People in Ottawa could look across to the bright lights of Hull just next door. This is thanks to the massive rebuilding that was required after the 1998 ice storm. Having to transmit power from damns way up north down to the south (the longest-distance power lines in the world, i believe) also means they had to learn how to deal with the effects of solar flares on power transmission. So basically if anybody knows about the issues that affect power lines, it's these guys.
___
Cogito cogito, ergo cogito sum.
I just got an arrl newsletter telling all of their members to contact their congressmen and tell them what a bad idea this is. Apparently, according to ARRL research, broadband over powerlines causes significant interference not just in ham bands but across the spectrum. Although I havn't exactly looked at the research in detail, I can't see how the power companies could avoid interference. Powerlines aren't shielded, and for any reasonable bandwidth to be passed through the powerlines, the frequency would have to be high enough that a significant amount of power would have to be used. Unshielded wire is always agood antenna, and for some situations the best. Granted it won't be well tuned, but I've seen worse situations cause a lot of interference. My home is near high voltage power lines (read a large part of San Francisco's power) and even at 60hz, I get interfering harmonics all the way up into 10 meters. Avoiding electrical grid contamination is something every ham has fought with. Hopefully I'm wrong, but unless there is some way of preventing interference, this seems like one of those thngs that will be really good for pacbell and really bad for the rest of the wireless world.
I think it's been mentioned here on slashdot before, but broadband-over-powerline systems have many drawbacks. Because power lines are not shielded, they will act as very effective radiating antennas for the signals they carry. Many of the proposed broadband systems utilize frequency ranges that overlap military, emergency, commercial and amateur radio bands, with the potential to cause a great deal of harmful interference to users of those services. Many countries, including Japan, the UK, and the Netherlands have already rejected broadband-over-powerline technology for this reason. Check out this page for more info:
http://www.arrl.org/tis/info/HTML/plc/
The fact is that even DSL causes interference, because the twisted-pair phone wires weren't designed to convey those high frequencies and leak like a sieve. Now, go to power lines, which are not twisted-pair, have no form of shielding whatsoever, and simply aren't designed for frequencies over 60 Hz. They radiate like antennas.
Traffic lights take very little bandwidth to operate, generally they are on a 200 KHz system that works like the X-10 switches many people have in their homes. It's not good for much more. The claims of greater bandwidth than cable or DSL are absurd.
Bruce
Bruce Perens.
And of course the BPL providers don't care how much they pollute the radio spectrum.
Bruce
Bruce Perens.
Here in Denmark several projects about bringing Broadband to users through powerlines has been abanded. The costs up-front for the avarage user are just to high compared to establishing an ADSL-connection.
Phone lines are twisted, so they don't tend to radiate much of the radio energy that's poured into them. HomePNA kicks out some noise but it's nothing compared to BPL.
Power lines are widely spaced, unevenly spaced, and not twisted. From the perspective of a radio signal, power lines are not transmission lines: they're antennae! BPL also works over much longer distances than HomePNA, meaning that the power levels involved are much larger. Dumping tons of RF onto the power grid will simply turn it into a massive radio jammer.
John Q. Public should be worried. In times of civic emergency, ham radio operators need all the spectrum they can get. Find a local amateur radio club and attend a meeting -- you'd be surprised how much stuff goes on behind the scenes. Hams are hobbyists, refining their equipment and honing their skills "for fun", but then swinging into action during emergencies to maintain communications when other methods fail.
Destroying a large chunk of the radio spectrum will not help anyone. BPL is technically inferior to cable and DSL, and it's only being hyped by those who see opporunity for profit without regard for technical or civic responsibilities.
then you probably have cheap enough DSL. There are 66 DSL providers, according to Canadian ISP. I don't know how much cheaper than $20 CDN (that's about $15 USD) you can expect. You can expect to pay $30 CDN for higher-than-average speeds (1700kb/s down, 300kb/s up), and/or no caps. Let's see power line internet beat that.
"Now gluttony and exploitation serves eight!" - TV's Frank