Broadband over power turns on both sides of the Atlantic Sending broadband signals over electricity cable has always confused people. The Home Plug Alliance, began life offering a way of sending broadband signals around a home, and then started working on ways to bring broadband to the home with a related technology, while the Universal Powerline Association sort of did the opposite …
I figure someone reading this may have an answer.
Now that they've cracked the powerline transmission problem, doesn't this offer us a new platform for P2P? Surely we should now be able to connect directly with our neighbours rather than going through an ISP...
If not, why not?
If this is workable, why is it that only BT is interested and that too only for IPTV (money/subscription- I guess) and not for actual Broadband?
Maybe the goverment should insist mass adoption, that way BT stranglehold on Adsl removed, Level playing field for all comers and lower costs for Consumers. Only those ISPs will win who can then provide good service and content.
Now that would be "Broadband for all in Britain" really at work. Are you listening Mr Brown ? Or is he in the Big Biz pockets and too many vested interests not allowing this mass adoption ? I SUSPECT SO !
"BT said that it rigorously tested all networking technologies and found DS2 chips deliver excellent IPTV viewing capabilities. "
BT also said, prior to launching BT Vision, that the live services would work over lines down to 2Mb. Now the live services need 4Mb and up. Oh dear, I wonder what happened. I also wonder what they might mean by "excellent IPtv viewing".
Wow.... that Duke Energy is Boss. Real Cool Stealth if they are Virtualisers.
Do you think the Internet would ask if they were into Cold FusionXXXXHot Fission ...in a Pragmatic CyberIntelAIgent UnderGround Maze of Networks. In Order, 42 Protect the Core.
A ZerodDay Trade in Virtualisation for Options, Derivatives, Futures, Mutuals and of course, the King of Present Fools, Hedge Hoppers.
There's an Unconditional Offer in there somewhere for anyone Real Bright and Bold as a Lion . :-) ......and it will be a step into the Wild Side of Life. :-)
Now that's an interesting Planet to Visit.
The frequencies which powerline broadband uses are blocked by the coils in the traditional domestic electric meter. That's part of their approach to "security" and/or coexistence. So the HomePlug stuff is for *inside* the home, doesn't connect to, can't interfere with, other Homeplug kit in homes on the same circuit. Don't know what happens if the electric meter is one of the trendy new "all electronic" ones though.
The same goes for the use of the "last mile" power network for broadband access. The signal from the distribution point at the substation can't get through the electric meter, so an electronic bypass device is needed to get the signal past the meter.
Powerline broadband as a "last mile" technology is dead anyway, just ask Keith Maclean at SSE Telecom, former superstar member of the PLC Forum, till SSE abandoned their "full commercial rollout" in Winchester before it had even started.
This has been around for ages...at least 10 years.
The problems encountered are interference to radio reception. Not the FM band but the lower HF frequencies.
Plus, of course, the fact that every transformer would need its own "modem", since the winding of same are good at coupling 50 hz but crap at doing the same to the 1-30 mhz frequencies.
The laws of the land do not allow for any system to cause any interference to radio, it being illegal. So if it is adopted (and it probably won't be) it will make life a bit impossible for GCHQ...and so many segments will have to be programmed out of the coverage that it would be reduced anyway. There are some fairly major legal challenges being mounted in the USA to the system....And then there are the problems caused by high strength signals near the powerline....which tend to be rather blocking....there are a lot of amateur radio stations out there....all capable of running over 200 watts of power...
There are just too many problems with broadband
on powerline for it to work for large scale roll out the power grid is a bigger mess than the old copper here in the US and likely not to get any better ever.Of course it would be nice to have another option that just isn't a practical one here now maybe on the other side of the ocean it's more feasible I wouldn't know.
Look, the signals don't really go over the power line, that just acts like an antenna (and not a very good one at that). In addition, if you get 200MHz of bitrate and then split up over 200 people (who will probably interfere with each other anyway) you don't get much.
As for the electric meter shunting out higher frequencies (over 50/60 Hz), just about everything does that in power condiuctors (on purpose). Lots of things you plug in have line filters which (guess what!) filter out high frequencies (FOR THE ENTIRE HOUSE!). The whole thing is a BIG waste of effort. Better to string up DSL terminals which would work MUCH better, and be MUCH more cost effective.
Broadband over power lines is an exceedingly bad idea, and should never have been allowed to be mentioned in company.
Let's completely ignore for a moment the differing requirements for a power transmission line (where you want most of the energy that you pump into it to come out of the other end, waveform distortion be damned) and a signal transmission line (where you want the waveform at the far end to resemble as closely as possible the waveform that you fed into it, and don't mind losing a bit of energy to resistance if it helps you achieve that sort of fidelity).
What you don't want in a transmission line of any kind is radiative loss or pickup -- that sort of thing is strictly for antennas.
Look at any cable made for carrying high frequencies and you'll see one of two constructions: either two stiff wires twisted around one another in intimate proximity, or an inner insulated core with a hollow braid surrounding it. This isn't just for the sake of prettiness. The co-axial construction surrounds the signal conductor with a heavy-duty earth conductor, preventing any interference from getting in or out (and having such a low resistance as effectively to have no potential difference along itself). The twisted pair construction depends on being used in a balanced configuration (i.e. when one wire is driven high, the other is driven low and vice versa) and works without a shielding conductor -- in effect, each wire is shielding the other (but only as long as one is high and the other is low).
Power lines were erected for carrying low frequencies. At 50Hz, which is the frequency of the mains in the civilised world, you have a wavelength of 6 megametres; so cold, hard physics says no power line anywhere in the UK (about one megametre all the way from Hampshire to Aberdeenshire) will ever radiate much energy out. But if you were to impose a high-frequency (and therefore shorter wavelength) signal on a power cable, it would make a marvellous antenna, radiating far and wide. In fact, many radio alarm clocks actually use the power cable as a receiving antenna; the domestic ring main picks up a nice strong signal in the 88-108MHz broadcast band, and with all the electronics being fully self-contained inside an insulated enclosure, there are no external connectors to worry about being live.
To transmit one bit of information, you need at least two crests and two troughs of signal (or one crest, one trough and a gap; or maybe one crest and one trough at half the frequency, which still takes the same amount of time). 8Mb/s broadband requires a carrier frequency of 16MHz. And that's for just one user. In a digital system, time-domain multiplexing is the simplest way to increase the number of channels. Of course you have to increase the bit rate, and therefore the carrier frequency; so to carry 100 channels of 8Mb/s, you need a carrier frequency of 1.6GHz. Power lines were never meant to deal with that!
All this RF energy being radiated from power lines is going to play havoc with radios, TVs, mobile phones, two-way radios (as used by the energency services) and all manner of electronic apparatus. Including landline telephony and other broadband users.
That is just how it is, and Mother Nature won't listen to any amount of smarm, spin or bribery.
Ever since this Power Line Controller stuff started springing up, I've been tempted to do a BOFH and ask people to "test" PLC capabilities with the traditional etherkiller:
http://www.fiftythree.org/etherkiller/
Now that Ethernet-over-mains is technically possible, at least someone might fall for it.
Ever since this Power Line Controller stuff started springing up, I've been tempted to do a BOFH and ask people to "test" PLC capabilities with the traditional etherkiller:
http://www.fiftythree.org/etherkiller/
Now that Ethernet-over-mains is technically possible, at least someone might fall for it.
Mr(?) Stiles sir, I'm not sure whether you're oversimplifying, or confused.
ADSL (the original "up to 8Mbit" one) uses a bandwidth of not much over 1MHz. This may appear to break Shannon's wotsits but in reality it doesn't because a phone line is (as you rightly point out) a nice relatively clean transmission line (unlike a mains power network) whose signal to noise ratio allows the transmission of more than one bit per second per Hz. IE if you've got 1MHz of reasonably clean bandwidth you can get more than 1Mbit/s raw data down it.
The "up to 24Mbit" in ADSL2+ uses around twice as much bandwidth but in order to achieve decent speeds requires a particularly low noise signal ie short lines only.
Modern consumer electronics often emits RF noise all over the spectrum that the PLT people want to use, so the available signal quality isn't much to write home about.
One of the most worried sets of folks when Scottish+Southern Electric were playing powerline broadband here in the UK were some other electricity companies, some of whom use unlicenced RF spectrum (433MHz, iirc) for wireless telemety, remote sensing, etc. These are typically low power radios and were considered to be at significant risk from the harmonics and stuff which would be present if PLC/PLT really took off and their signals splattered the airwaves 24x7 (433 MHz is also used by RF keyfobs etc but they're not exactly transmitting 24x7).
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