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Utility Cuts Short BPL Trial 239

Posted by timothy
from the bzzzzzzt dept.
fatboy writes "The ARRL is reporting that Alliant Energy has called an early end to its broadband over power line (BPL) pilot project in Cedar Rapids, Iowa. The "evaluation system" went live March 30, and plans were for it to remain active until August or September. Alliant shut it down June 25. Ongoing, unresolved HF interference from the system to retired engineer Jim Spencer, W0SR, and other amateurs prompted the ARRL to file a complaint to the FCC on Spencer's behalf demanding it be shut down."
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Utility Cuts Short BPL Trial

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  • by cliveholloway (132299) on Wednesday June 30, 2004 @03:05AM (#9568704) Homepage Journal

    "unresolved HF interference from the system to retired engineer Jim Spencer"

    It must be bad if poor old Jim was interfered with.

    cLive ;-)

    • by afarhan (199140) <{farhan} {at} {phonestack.com}> on Wednesday June 30, 2004 @04:26AM (#9568995)
      Sending data over power cables is the first thing that strikes us when we think of broad-band. As someone involved with broad-band initiatives in india, as a veteran slashdotter and as an ex-ham, i think this needs a few pieces of missing information.

      Why power lines? because they are there. More importantly, because you cannot touch any other copper lines (like ma'bell) nor lay them afresh without being billg hisself. now guess who demands this money? the very FCC!

      It is often a cheaper and a simpler solution to just run a shielded cable. In India, where such zoning and municipal laws are lax, I have a 100 mbps ethernet drop into my home office. The electic poles are tapped for feeding the hubs on the way as well as providing the physical support for the cable high above the reach of straying cows, buffalos, kids on bikes and cable thieves.

      The cable operators pay the electricity folks a fixed low per-pole charge. In the case of BPL, i think it is more of FCC trying to save the phone companies than creating a new last mile solution.
      Why can't we lay more cable in anycase? it is a cheaper option.

      The point often missed about HF is that like ozone layer, it really affects the entire world. I have a 5 watt transceiver that regularly goes around the world (www.phonestack.com/farhan) using just a 10 meter stretch of wire for an antenna. the noise that BPL will generate can easily disrupt global HF communications that form the backbone for many countries even today. Imagine the interference BPL would create by contributing megawatts of power radiating over millions of miles of wires all over the country.

      blaming amateurs is really a shame. especially at slashdot. from the early open source tcp/ip (the KA9Q) to Alan cox. Amateurs have frontlined development of Internet. the very idea of personal science (as something that individuals pursue for pure satisfaction) that propels towards free and open softwares finds its foundations in amateur radio.

      Amateur radio is really the only open source communication technology. Everywhere else, you still pay per use. It is also the classic peer to peer technology, it requires no 'service providers' at all just you and a couple of transistors connected to a clothline. The entire communication stack (read morse code decoder) is in your head. how's that for a setup?
      • I seems to me that if power companies want to use power lines for data transmission they should find some way to shield them. Perhaps this is too expensive. If so, run fiber or coax.

        Perhaps as power lines are replaced or upgraded they could be replace with shielded lines suitable for data transmission use. I suspect that it would be cheaper just to run addtitional fiber when doing the replacement, but perhaps not.

      • That's funny. When I think of broad band I think of the Go-Gos and The Bangles.
  • by alanhyee (680084) on Wednesday June 30, 2004 @03:06AM (#9568707) Journal
    I happen to live in the Cedar Rapids/Marion area and I didn't even know this was there. Why doesn't anyone tell us anything?! It would be an alternative to Mediacom and Qwest.
  • As a UK radio ham (Score:5, Interesting)

    by CountBrass (590228) on Wednesday June 30, 2004 @03:08AM (#9568718)

    I'm incredibly glad to hear this. BPL has the potential to kill ham radio (and actually lot's of other HF radio services) as it uses HT powerlines that were not intended to carry HF signals and act as really excellent antenna (in fact the US Navy uses them to transmit extremly low frequency/long wavelength signlas to its submerged subs! So we know they work as antenna!)

    I'm also glad the FCC isn't actually as big a patsy of the BPL industry as it first appeared. Cheers to the FCC and let's hope this is the first nail in the coffin of a truly bad idea.

    As an aside: I hope this discourages the power industry muppets in the UK from trying the same thing.

    • by mcpkaaos (449561) on Wednesday June 30, 2004 @03:14AM (#9568748)
      You got all of that from Art Bell you big faker! ;-)
    • by ScouseMouse (690083) on Wednesday June 30, 2004 @03:17AM (#9568757) Homepage
      They already tried. They already failed for much the same reasons, except i believe it was also interfering with LW and AM radio signals.

      You dont mess with the BBC's signal in the UK. The phase "Ton of bricks" does not give justice to what will happen
      • The phase "Ton of bricks" does not give justice to what will happen

        You have to remember it's a metric ton.

    • by obey13 (731453)
      let's hope this is the first nail in the coffin of a truly bad idea.
      How is BPL a bad idea? Aside from the problems that need to be worked out with interference with hobbists, this could be a legitimate alternative to dsl and cable. It would be wonderful if a bit of competition could make broadband a little more prevalent/affordable.
      • by Anonymous Coward on Wednesday June 30, 2004 @03:30AM (#9568816)
        The big problem with BPL, as was stated by a poster in a previous article, is the wire. Unshielded transmission line will create signals that interfere with radio service. Unshielded wire will also act like a big antenna and pick up noise, thus limiting the bandwidth of the data the line can carry. Replace the wire with something better, and well, you don't have broadband over power lines any more. You will, however, have a workable system without the interference problems.
        • Re:As a UK radio ham (Score:5, Informative)

          by NewtonsLaw (409638) on Wednesday June 30, 2004 @06:00AM (#9569217)
          Unshielded transmission line will create signals that interfere with radio service.

          Not necessarily so.

          Unshielded balanced feeders have been widely used ever since the introduction of RF transmission and the losses can be lower than a sheilded cable if done properly. Leakage will always be slightly higher -- but can still be extremely low providing the lines are balanced properly.

          Many years ago I built a balanced unsheilded RF link that was over a mile long on a farm for a CB radio. With an input power of 500mW and a matched dummy load on the other end, the leakage from that feeder was so low as to be almost undetectable beyond a few tens of yards.

          I expect that the problem the BPL trials are having is that the power circuits are not balanced at the RF frequencies (or harmonics thereof) that are being used.

          Achieving and maintaining high levels of balance across the entire spectrum being used is probably going to be a *major* problem that will stand in the way of this technology.
          • the leakage from that feeder was so low as to be almost undetectable beyond a few tens of yards

            i'm not sure what it's like where you're from, but around here, power lines are tens of yards from each other. from a single line, it's probably no big deal, but when the lines criss-cross like a giant arial antenna, everywhere you look, then you start to have bigger issues.

            perhaps it's not such a bad idea, but better saved until all of the utilities are under ground.
          • If power lines were balanced the way your wire was, there might be less of a problem. It might be even less if you twisted that ladder line, too. But to expect power line to be balanced that well, it's just impossible. The pole, wire, and transformer plant is not very much like your ladder line.

            Bruce

          • Re:As a UK radio ham (Score:3, Informative)

            by SirTreveyan (9270)

            Many years ago I built a balanced unsheilded RF link that was over a mile long on a farm for a CB radio. With an input power of 500mW and a matched dummy load on the other end, the leakage from that feeder was so low as to be almost undetectable beyond a few tens of yards.

            As someone with a little common sense I find your assessment of the BPL situation based upon your little project immensely stupid for several reasons. They are as follows:

            1. Broadband over power lines is being considered for only one

      • by Tony-A (29931) on Wednesday June 30, 2004 @03:49AM (#9568896)
        How is BPL a bad idea? Aside from the problems that need to be worked out with interference with hobbists, this could be a legitimate alternative to dsl and cable.

        Imagine running gigabit ethernet over silver-satin telephone wire.
        Now imagine applying several thousand volts to the same wires.

        The problems are not just with the hobbiests, they're just the first to notice because they happen to be interested in such things.
      • by havana9 (101033) on Wednesday June 30, 2004 @03:58AM (#9568926)
        The problem is twofold.
        First of all on HF spectrum there are not only amateur radio operators: ships, aircrafts, military, private services, broadcasting stations and so on.
        If there is an harmful interference to an amateur radio station it could be as well exist an harmful interference to an international airport or a coast guard station. And they can't hear an airplane or a boat distress call.

        Using wires made for 50/60 power to transmit data
        at high speed is a bad idea because the infrastructure was made to transmit power: the impedance is low and variable, cables aren't paired or shielded, and there is a lot of noise.

        Power utilities have a right of way, so to have another competitor they have only to pull optical fibers along with power lines and put a WiFi/UMTS
        base station on the poles (or a 10BaseFL/100BaseFX/1000BaseSX switch and pull fiber to the homes).
        Better badwidth for users, no interferences to and from other services and appliances, and a working technology.

        • Re:As a UK radio ham (Score:4, Interesting)

          by stiggle (649614) on Wednesday June 30, 2004 @05:16AM (#9569121)
          The right of way only exists for the power lines.
          It does not exist to pull fibre or install any equipement not related to the transmission of the power.

          Energis found this in the UK when some farmers actually knew their rights and stopped them working on putting their fibre on the high voltage transmission lines.
          • Why did people object to the fiber? Compared to HV lines, it's a tiny piece of cabling.
          • The right of way only exists for the power lines.

            Odd, but that's not generally the case here in the States, IIRC - typically public rights-of-way are established for any or all utilities. That is, once the ROW has been established for the power company, the phone company and sewer company can piggyback along that same ROW, and the power company can also use the same ROW for other public services as well. I personally know of at least one power company currently stringing fiber along their existing righ

            • But a railroad, on the other hand, is another matter. There's been at least one case in the USA where a railroad company lost its rights to fiber lines it had buried along its tracks... because it had buried them. Turns out that the railroad didn't own any subsurface ROW along the tracks.
        • Re:As a UK radio ham (Score:5, Interesting)

          by ross.w (87751) <rwonderley@g m a i l.com> on Wednesday June 30, 2004 @07:32AM (#9569474) Journal
          Optus and Telstra did this in Sydney with cable TV.

          Lots of public protest about the extra overhead cabling forced them to stop, and now they aren't doing any new suburbs, because underground is too expensive, so those of us who live there have to use satellite TV and ADSL.

          In Canberra, TransACT have put fibre to your house strung on poles as well. Although the poles in Canberra are at the back of people's houses, not the front, so no-one seems to object. Again though, new suburbs with underground power don't get it for a long time yet.
      • by GomezAdams (679726) on Wednesday June 30, 2004 @04:08AM (#9568958)
        First off, there are many services using radio spectrum in the HF regions where the interference takes place. Get a short wave radio and you can hear all sorts of long distance communications taking place by airlines, shipping, military, news services, governments, short wave broadcasters, and so forth. They also have a right to clear communications.

        These hobbyists, who use a very small portion of the frequencies in question, include a large number of people who are active in public service sectors for emergencies and for the public welfare in general (for free and providing their own equipment), such as providing free phone patch services for the military in remote areas to call home. In emergencies when the local utilities go out, getting traffic into unaffected areas is very important and if that receiving area has BPL interference than life and limb could be in jeopordy.

        BPL is supposed to conform to the existing rules and regulations in place stating that no service is allowed to interfere with another. Period. All these other services have to conform and just because a few people want to make money off the BPL for a few people at the expense of all others does not give them the right to use an unsound technology to do it. If they can come up with good technology that doesn't cause problems than by all means go ahead. And BTW, what are you going to do if you have a transmitter of any service located nearby that continuously knocks out your BPL link? Nothing. BPL is a Type 15 service that has no legal recourse when it is interferred with. BPL as current technology is broken and most likely cannot be cleaned up without massive expense (guess who pays) and investment in a much different type of equipment than is proposed. The power companies want to use the current equipment for BPL because it is cheap. If they have to build a different technology than it is no longer going to be cheap.

        Plus what will happen should BPL go through is that the power companies will lease the grid to the existing ISPs and your fees will likely remain within a few percentage points of existing services over POTS and cable anyway. The idea is to make highspeed internet available to all, not to keep your price down.

      • by juhaz (110830) on Wednesday June 30, 2004 @05:14AM (#9569113) Homepage
        It's bad idea because those "problems that need to be worked out" CAN NOT be worked out.

        You can't "work out" laws of physics, and laws of physics say that large bandwidth over this kind of wires cause interference to just about everything, not just few hobbists.

        You need new cables for broadband, and if you put in new cables then it's easier (=cheaper) to just go DSL route.
        • large bandwidth over this kind of wires cause interference to just about everything, not just few hobbists.

          Nasty hobbists! Greedy hobbists! Smeagol should KILL the nasty hobbistses!

          --Rob

    • Re:As a UK radio ham (Score:4, Interesting)

      by FireFury03 (653718) <slashdotNO@SPAMnexusuk.org> on Wednesday June 30, 2004 @03:21AM (#9568775) Homepage
      I hope this discourages the power industry muppets in the UK from trying the same thing.

      AFAIK BPL was already tried and rejected in the UK for exactly these reasons a couple of years ago.
      • by Mike Dolan (689707) on Wednesday June 30, 2004 @05:38AM (#9569165)
        AFAIK BPL was already tried and rejected in the UK for exactly these reasons a couple of years ago.

        Nope, it doesn't appear to have been fully rejected. Scottish Hydro Electric appear to offer the service. Website with details here:
        Scottish Hydro [hydro.co.uk]

        Cheers,
        Mike
      • Re:As a UK radio ham (Score:3, Interesting)

        by Alioth (221270)
        The MEA (Manx Electricity Authority) in the Isle of Man are thinking of doing broadband service.

        However, they laid fibre everywhere they put in new power lines. I suspect the power line delivery will probably be the last 100 yards to the house, where the cable is already a few feet underground. It'll be interesting to see what their plans are.
        • I thought the Isle of Man had a lot of DSL already anyway? (I certainly remember seeing DSL adverts while I was on holiday there a few years ago, long before most of England got it).
          • The Isle of Man has complete ADSL coverage (the last exchanges were only done at the tail end of last year, Manx Telecom were very reluctant to do the small exchanges with perhaps only a few hundred subscribers, but I think the availability of micro DSLAMs may have made it feasable).

            The problem is that Manx Telecom is a private monopoly that likes to charge a lot of money for business services (they can't get away with it for home services because too many people would whine to the government, and their co
    • (in fact the US Navy uses them to transmit extremly low frequency/long wavelength signlas to its submerged subs!

      No, it doesn't. The Navy has specific special-purpose antennas for that purpose. It does not use powerlines.

      Sure, they look like [fas.org] power lines, due to the fact that they're metal wires strung overhead on poles, but they're not feeding AC to anyone's toaster or television, and total radiated power is a handful of watts.
  • by panurge (573432) on Wednesday June 30, 2004 @03:12AM (#9568740)
    • Put up power lines - = huge aerial system
    • Inject wideband RF into huge aerial system
    • Interference!
    In fact the whole idea of RF over power lines, though attractive at first sight, is a triumph of will over physics. A system designed to take kilovolts at around 50-60Hz, with mechanical switches all over the network and a mixture of capacitors and inductors to adjust power factor, is not a benign environment for RF. But people keep trying to do it. There have been attempts at LANs over household wiring - but wireless networking has just about killed that with a combination of speed, convenience and safety.

    You can adapt a car to travel on water, but the result is expensive and technically poor. In the same way, I feel broadband over AC power is a cross-model step too far.

    • by Kris_J (10111) * on Wednesday June 30, 2004 @03:31AM (#9568825) Journal
      You can adapt a car to travel on water, but the result is expensive and technically poor.
      Won't stop Branson trying to break a record in it though.

      Just because something's hard doesn't mean it shouldn't be done. Otherwise, why would you go to the moon or do those other things?

      • Won't stop Branson trying to break a record in it though.

        He broke the record; Travelling the 22 miles frm England to France in less than two hours using a Ford Aquada (works out to be around 12 miles/hour).

        "Missed the last ferry sir? Just drive down that ramp down there; take a left at the harbour wall, and keep going until you see the European continent."
      • Just because something's hard doesn't mean it shouldn't be done. Otherwise, why would you go to the moon or do those other things?

        Yes, but how many people have gone to the moon? And how much did it cost?

        If everyone wanted to go to the moon, and you had a Saturn V launching from the pad down the street every few hours...I hope that's not regular glass in your windows.

        Just because something's hard doesn't mean it should be done. BPL seems to fit into that category. Like going to the moon, it may be a

      • Just because something's hard doesn't mean it shouldn't be done. Otherwise, why would you go to the moon or do those other things?

        Giving up on something that is hard is a good idea when there's an easier way to achieve the exact same thing. Delivery of high speed internet over powerlines is hard. But it's pointless in the face of cable, DSL and satellite internet.

    • The US and British military have turned tanks into boats before. =)
    • In fact the whole idea of RF over power lines, though attractive at first sight, is a triumph of will over physics. A system designed to take kilovolts at around 50-60Hz, with mechanical switches all over the network and a mixture of capacitors and inductors to adjust power factor, is not a benign environment for RF

      Change 60 Hz to a few kilohertz, and you've described the phone system. Yet, DSL works.

      • Change 60 Hz to a few kilohertz, and you've described the phone system. Yet, DSL works.

        It's nothing like the phone system. The phone system is much lower current (and radiation is therefore proportionally less). It uses twisted pair, which cancels the magnetic field of the signal in the wire, reducing radiation even further. And it is commonly buried underground, where the moist soil acts like conductive shielding, instead of being strung high in the air on poles.

        And the signal isn't even analog the en

  • RF interference. (Score:4, Informative)

    by ScouseMouse (690083) on Wednesday June 30, 2004 @03:14AM (#9568747) Homepage
    This is exactly the same reason that a Broadband over power lines experiment was given up by one of the UKs power providers (The predecessor to Scottish power I think).

    I wonder why someone thaught it would be different in the US, even with its more stringent laws about RF interference.

    Do these people not do basic searches on prior work?
  • That was dumb... (Score:3, Interesting)

    by Shirloki (563610) on Wednesday June 30, 2004 @03:21AM (#9568772)
    I remember something like this being tried about 5 years ago. It had the amateur radio community in an uproar. Something to do with street lights re-radiating the high-speed internet data in the form of electromagnetic energy. Apparently they did little to fix it. Shame; I wanted to be the first one on my block to have the other cable.
  • Weird coincidence (Score:4, Interesting)

    by farmhick (465391) on Wednesday June 30, 2004 @03:21AM (#9568776) Homepage
    I just received my July 2004 issue of PC World today, and glanced thru it. This exact project was mentioned, on page 36. I wonder if this will become a collector's item now. ;^)

    The last paragraph is quite telling actually:
    Another hurdle: BPL may interfere with radio signals. The Federal Communications Commission is considering rules to forestall such problems, but those rules won't be finalized for months.
    That BPL means 'Broadband over Power Line', by the way.
  • by ofdm (748594) * on Wednesday June 30, 2004 @03:30AM (#9568819)
    One thing in the article is cute - the Power Line people invited the ARRL to be involved
    The ARRL became involved in Spencer's case after United Power Line Council President William R. Moroney invited the League in mid-March to keep his organization in the loop on any cases of BPL interference that were not being satisfactorily addressed.
    and the ARRL have repaid them by asking the FCC to close them down and fine them $10,000:
    rhe ARRL's formal complaint to FCC Enforcement Bureau Chief David H. Solomon called on the Commission not only to close down Alliant's BPL field trial system but to fine the utility $10,000 ...

    Nice. I'm sure comms companies all over the US will jump at the chance to get the ARRL's contribution and involvement in future.

    Either way, it's great to see that the FCC is standing firm to protect sad lonely guys holed up in their bunkers listening to strangers over the airwaves from the interference of sad young(er) lonely guys holed up in their bunkers looking at strangers over the ether.

    • by Barbarian (9467) on Wednesday June 30, 2004 @03:38AM (#9568851)
      There is much more [grove-ent.com] than sad lonely guys in their bunkers involed in interference on the HF bands. If you go to that link, most of the frequencies are labelled Army, Navy, Air Force, Coast Guard, emergency response, etc.. All these would be subject to inteference out by widespread BPL deployment.
    • by CountBrass (590228) on Wednesday June 30, 2004 @03:38AM (#9568852)

      "Yeah we invited the local neighbourhood watch over so they could let us know whether they had issues with us burgalirising a few of our homes. Boy were we pissed when they reported us to the Police and we were all arrested. That's the last time I invite them"- Bill "Respect" Moroney.

      If something is a illegal (and causing radio interference is and the BPL companies know it: they've been told often enough) then it's a crime: the fact that they invited the people affected along to watch doesn't change that fact and they should expect to be told to stop and be punished for it.

      • This is more like telling your neighbours that you're going to have a party and to contact you first if it gets too loud, only to have them contact the police first instead.
        • by juhaz (110830) on Wednesday June 30, 2004 @05:23AM (#9569133) Homepage
          Bullshit.

          Radio interferences is much bigger problem than few neighbours losing their nights sleep, there's all kind of important systems running on the radio bands, not just few ham hobbyists. Not to mention how much larger area it affects.

          You don't think it's reasonable for neighbours to contact the police if you're jamming loud enough that it keeps the whole city awake, and no less than THREE MONTHS IN A ROW?
        • No, it's more like telling your neighbours that you're going to have a party and to contact you first if it gets too loud, they do, and then you get upset that when you don't stop, they call the police anyway.

    • Without ham radio operators you would not have half the communication technology you have today.

      I suggest you post your full name here so many of us in search and rescue as well as RACES and SKYWARN can be sure to give you "extra" help when a natural disaster hit's your area.

      Ham radio is a vital service to the community, just because you are too narrow minded or incapable of grasping the concepts of the hobby, (Hey, not everyone can take the test and pass) does not mean it's does not have a huge value to
    • i think I have heard HAM guys complain about wireless and now BPL for a while and I suppose I will come off as a troll, but WTF?!?!?

      I know that many of you do HAM stuff as a fairly serious hobby, but how can you justify the screeching halt of progress so that you can chat with friends across the globe? OK, some of you talk to your columbian distributor that way and I'm sure you make some good dough, but the rest of you are somehow justifying that the doctor on that corner shouldn't have the ability to get
  • Collins Radio (Score:5, Insightful)

    by Baldrson (78598) on Wednesday June 30, 2004 @03:35AM (#9568840) Homepage Journal
    Cedar Rapids was one of the focal points of radio technology during its early days. Its rather funny to see this experiment, so inimical to wireless, carried out in the origin of much of wireless technology.

    Somehow the defeat is poetic justice.

  • From my perspective (Score:5, Informative)

    by Creamsickle (792801) on Wednesday June 30, 2004 @03:41AM (#9568862)
    I live in Cedar Rapids and participated in the program. I didn't RTFA so I'm not sure what it says about this, but the mailer I got a couple days ago didn't say anything about a complaint, it just basically said Alliant had met its goals for the program ahead of schedule, and after working out a few issues there is a possibility the system may be implemented on a larger scale.
  • by Anonymous Coward on Wednesday June 30, 2004 @03:43AM (#9568873)
    I've never understood why they were so gung-ho about this stupid idea in the first place when most power grids already have multi-core fiber optic cable hidden inside the neutral wire. (they use it to communicate between substations and most of the capacity is dark - I put hundreds of miles of this stuff in the air back in the mid-nineties so I know from whence I speak) The power company already has the most valuable easements. Couple that with their existing fiber grid and they could have fiber to the curb in every major market for a lot less than the phone or cable companies who very often have to mount on existing power poles and pay $1 or more per pole for easement rights.

    That's how SPRINT became a major Playa in the long distance and later, the backbone market - they used their existing easements. (for those who live in a cave, SPRINT stands for Southern Pacific Railway INTernational - your phone call 'rides the rails'...or more precisely, runs over fiber optic plowed into the roadbed of their gigantic network of railroad tracks)
    • I've never understood why they were so gung-ho about this stupid idea in the first place when most power grids already have multi-core fiber optic cable hidden inside the neutral wire.

      What neutral wire? There's no neutral wire up on the poles. When you see three wires up there, that's one wire for each phase. In residential neighborhoods, you'll see a phase tapped off to feed a transformer. The output of the transformer feeds each house through two wires, each wire being a 120-volt leg, with 240 volt
      • by thogard (43403) on Wednesday June 30, 2004 @04:15AM (#9568968) Homepage
        What neutral wire?
        Neutral, ground ... its all the same with 3 phase. When you look at the 3 wires, you will find a forth ground line above them all that should take the volts of a lightning strike and it helps the real big circut breakers work right when there is a major problem with a tower. The ground line is what they hang the fiber off of and some places have a coax like shield thats the ground path around the fiber.

        The problem is fiber doesn't like the wind action on poles and lots of that dark fiber is good for the distance between the poles and no longer.
        • That still doesn't make any sense. Yes, the ground wire is there for lightning protection, but not for the power distribution system. They use 3-phase Delta transmission, which only requires three wires. There is a Delta-Wye transformation done at some point to give you a neutral wire for use in buildings. There is no neutral wire in the main grid at all. Furthermore, to string critical communications fiber in a lightning cable is, well, suicide.
        • by lutz3 (634137)
          This is how the Energis transmission network in the UK is built. The fibre is wrapped around the ground wire at the top of the towers.
      • by arth1 (260657)

        What neutral wire? There's no neutral wire up on the poles. When you see three wires up there, that's one wire for each phase. In residential neighborhoods, you'll see a phase tapped off to feed a transformer. The output of the transformer feeds each house through two wires, each wire being a 120-volt leg, with 240 volts between them.

        How the wires are designed depends on where you are. In three-phase systems which you seem to be used to, it's common to have a ground wire shielding the others from lightn

    • most power grids already have multi-core fiber optic cable hidden inside the neutral wire.

      One question... What is the purpose of the "neutral wire" exctly? It certainly doesn't go to anyone's homes, since "neutral" in your house is actually grounded at your utitily box.

      I'm quite interested. What possible use is there for a neutral wire?
    • by isdnip (49656)
      Well, if you want to get picky, the name Sprint did not come from an acronym as you said it did; rather, the name "Sprint" was chosen from an employee "name the company" contest in the late 1970s. It was the Southern Pacific Communications Company at the time, but the SP railroad sold it shortly afterwards.

      Someone earlier noted that in the UK, Energis had trouble with their easements when they used power easements to run telecom. In the US this is not usually a problem for utilities, but it has been a pr
  • by taped2thedesk (614051) * on Wednesday June 30, 2004 @03:49AM (#9568898)
    If BPL was possible, it'd be in SimCity.
  • One word: Fiber. Seriously, just string fiber optic lines along your power lines, you can easily mount repeaters and whatnot on the power towers and then do your last mile with good old cat5 cables (Ok...fine, last 328 feet) terminating in a repeater at the demarcation point.
  • by evilviper (135110) on Wednesday June 30, 2004 @04:22AM (#9568986) Journal
    I think we all know what this means. Some poor sucker is going to have to go out and start twistng power lines together, to get a pair... Pretty soon, it'll be "PowerLinesTx"
  • I think there is an ongoing test in Cincinnati, Ohio. Anyone out there live there that knows if there have been similar complaints there?
  • Me think analog good thing. Disaster happen. Say chemical plant go boom. People go quick!! But only, me say, maybe eight police in whole small town!!!! Amateur people trained in MARS unit (funny name, huh?) help evacuate people. Good thing!

    Unfortunately, broadband over power lines isn't win-win if it means another form of communication is rendered useless. The FCC doesn't support an amateur radio service just because "we're the one's what love freedom!" Amateur radio operators routinely perform vol
  • by AgTiger (458268) on Wednesday June 30, 2004 @08:58AM (#9569861) Homepage
    ARRL Takes Issue with Public Funding of New York BPL Project [eham.net]

    See Alan Crosswell's site [columbia.edu] for more information on BPL interference in his area.

    All it takes is one location to roll out BPL, and the HF band is affected world-wide.

    I predict the following:
    1. BPL will eventually be regulated out of existence in the USA (by the FCC) and in Canada (by Industry Canada) due to the provable interference with the HF bands. This will not be just due to interference with ham operators - militaries still use the HF band.
    2. Manufacturers of BPL equipment, and the companies that developed the technologies therein, will be desperate to recoup costs. They won't want to see zero return on investment, or get stuck with an inventory that now is only suitable to be landfilled. They will turn an eye to selling in foreign markets, focussing on countries with less laws and regulation regarding spectrum management.
    3. A power utility company in one of these countries will bite, purchase, and roll out BPL.
    4. The ensuing interference will affect the HF band world-wide.
    5. There will be much bitter complaining from those suffering the HF interference, but in the end, they will either find a way around it, or they will effectively lose the use of the band.
    6. Assuming the HF band becomes unusable world-wide due to foreign run BPL installations, there will be great pressure on the FCC to drop any domestic prohibition on the technology, and allow full roll-out here.

    Before anyone says how heartless I am to those poor ham radio operators: I am one. I'm just a realist.

    • I don't think so. Imagine if some rogue country tried broadcasting and interfering in the RF spectrum. Other countries would come down on them hard.

      They may not have specific laws preventing that, but their government can certainly be effected by other nations if they don't play by the rules (think, embargo, etc).

      It won't happen. Unless BPL causes little to no interference then it will not be accepted anywhere. Period. The RF spectrum is limited and extremely important to so many things people do ev
  • by KC7GR (473279) on Wednesday June 30, 2004 @09:07AM (#9569930) Homepage Journal
    In any situation like this, someone invariably gets picked as a 'test case.' Jim just happened to be the one.

    What he experienced in terms of RF 'noise pollution' would become all too common if BPL were to be widely deployed. The NTIA report [doc.gov] and the ARRL's [arrl.org] own technical committee have demonstrated this in gruesome detail.

    Want some more real-life examples of the kind of crap BPL is capable of spreading? Go here. [vvara.org]

    There are plenty of existing ways to deliver broadband to homes without polluting the HF spectrum. BPL exists only to serve the pocketbooks of its equipment manufacturers, and the shareholders of power companies, at the expense of EVERYONE (not just amateur radio ops) who uses the HF spectrum. If it becomes widespread, commercial aviation, military, and the federal government's HF users will ALL be affected in short order, and it will probably get shut down anyway as a result.

    Why waste any more time on it at all?

  • Local QRM only? (Score:3, Interesting)

    by TheSync (5291) on Wednesday June 30, 2004 @09:49AM (#9570346) Journal
    Can anyone actually point to skywave QRM from BPL? Or is all the intereference detected so far local only?

    BTW, I find power lines locally interfering with AM broadcast mobile reception today, somehow we still live.
  • theory vs practice (Score:5, Informative)

    by ajs318 (655362) <sd_resp2.earthshod@co@uk> on Wednesday June 30, 2004 @10:49AM (#9570928)
    In theory, you can use almost any pair of wires to carry a broadband signal. That's because in theory, any pair of wires are perfectly conductive. Also, as soon as an extra electron tries to enter one end, another one drops out the other end, instantaneously, and if you try to pull an electron out of one end, another will be sucked in at the other end, equally instantaneously.

    It ain't like that in practice.

    Imagine a drainpipe stuffed with tennis balls. When you try to push in an extra tennis ball, what happens is that all the other tennis balls give a little, and for one fleeting instant there really is an extra ball in the pipe. Then the balls expand back to normal size and one is shoved out the far end.

    Now, any pair of wires will have a capacitance (since they are conductors separated by an insulator), an inductance (since they are wires; at low frequencies you need a full-on coil to get any effect, but at high frequencies any slight bend will do the job) and a resistance (since they aren't perfect conductors). It's what electrical engineers call a composite impedance, and what everybody else calls ..... well, they don't have a word for it, they call an engineer to fix it. But what you need to remember is that the potential difference (voltage) across a capacitor can only change gradually, never suddenly; and the current through an inductor also can only change gradually, never suddenly.

    For any given transmission line, if you stick a battery across the terminals at one end and a resistor across the terminals at the other end, look at each end with an oscilloscope and have some magical way of lining up the time axes, you won't see just a simple step change of voltage. When you apply the battery to the T.L., it looks like some composite impedance (which it is) and likely draws more current than the resistive load at the far end wants, since it's charging up the capacitance of the line -- or less than that, since it's charging through an inductance. One or the other phenomenon will win out every time.

    Once the capacitance of the line has charged -- via the inductance and resistance of the line -- it then begins discharging into the resistor on the far end. Actually, it doesn't wait at all, but starts discharging as soon as it has begun charging. And what you may even see, is a pulse of current reflected back towards the battery, if too much current went in at first compared to what the resistor was expecting. You can even get multiple reflections if the first one isn't exactly right. What you essentially see on the scope traces is a damped sine wave at the frequency at which the resistance and capacitance of the line resonate -- and a delay between applying power from the source and seeing it at the load.

    That's what you get with DC. With AC, the capacitance and inductance tend to distort the shape of the waveform, but not change the frequency -- though it's very likely that other frequencies will be added in. Also, anything under a few hundred kHz behaves mostly like DC -- albeit more-or-less-slowly-changing DC -- but broadband networks need carrier frequencies measured in MHz, and by the timed you get to that sort of frequency, the AC phenomena are well established.

    Now if all you are concerned about is getting the maximum energy throughput, as are the electricity board for example, then you want to minimise resistance (which turns energy into heat -- capacitance and inductance just store it in electric and magnetic fields, respectively, then give it up again) even if that makes the line highly capacitive or inductive. All that will happen is that you'll get a huge reflection the first time you connect up, then a series of ever-decreasing ones, but most of the power from your source ends up in the load even if it takes awhile to make it down the line, and even if the shape of the waveform is significantly altered.

    If you want a transmission line that does not
    • Never heard the term composite impedance used. I've always heard it described as complex impedance (to convey the fact that it's a combination of the purely imaginary reactance and the purely real resistance). Good term, though.

      The other point to make is regarding wavelength - unless a wire is at least lambda/10 in length, transmission line effects can generally be ignored. They're there, but not significant. At audio frequencies, this means you can have a wire of on the order of a half kilometer befor

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