back to article Power line tech could crash aircraft and shut down the Archers

An extensive study commissioned by Ofcom concludes that power line networking could crash aeroplanes and block Radio 4, but that technology will probably solve the problem before that happens. Power-line networking has been increasing in popularity, partly because BT bundles it with Vision, but pushing networking signals over …


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  1. ToW

    Im loving

    The ancient ghetto blaster and the fact he used (probably) P2P copy of Transformers in the test

    1. grunt

      Just what I was thinking..

      'transformers2.ts' TS as in telesync?

      Whinging about your ham radio not working? Fail.

      Testing your theories with pirated movies? Epic fail.

      1. Tom 38

        Not as in telesync

        You're showing your own pirated movie history here. ts in this context is almost certainly mpeg2-ts - MPEG-2 Transport Stream - which doesn't necessarily contain MPEG-2 data, it's also happy with MPEG-4 AVC.

        Typical procedure for ripping* a blu-ray under Linux normally ends with MPEG-4 AVC in a MPEG-2 Transport Stream, and since Transformers 2 is out on blu-ray, how about being a little charitable and assume it is his rip.

        * Or, for that matter, just playing it. I'm so glad that the MPAA made it impossible to actually use a blu-ray disk legitimately, whilst making it not exactly hard to use it illegally. Top marks, cocktards.

  2. Red Bren

    "help the local airport get planes on the ground"

    Gravity will do the job.

  3. Anonymous Coward
    Thumb Down

    Genie out of the bottle?

    So Ofcom, that toothless and incompetent wonder, has failed to do anything practical about interference from 14 Mbps, 85 Mbps and 200 Mbps Powerline / Homeplug technology over the last several years.

    What's the best way of dealing with the forthcoming Gigabit Homeplug technology? Of course! Get some consultants to write a lengthy report about it! Problem solved...

  4. Paul Crawford Silver badge

    Useless to**sers

    We had a whole range of Electromagnetic Compatibility laws introduced in the 1990s to stop equipment from causing unacceptable degrees of interference to legitimate radio users. And when this kit comes along and pisses all over the radio bands what do Ofcom do?

    Sweet f*ck all.

    Why is that you wonder? Well because there is money involved, and Ofcom appear to have been bitten by the Thatcher view that making money off radio use trumps almost everything.

    Why have they not prosecuted BT for their crap kit? I guess the same applies to Phorm fiasco where the big & wealthy businesses somehow get different rules applied...

    1. BristolBachelor Gold badge

      CE Directives

      In the UK, the chosen outfit to sort out CE violations is Trading Standards. Unfortunately, they seem to be a fragmented bunch of local council employees, and this could do with a national effort. (I don't know if / how well they could all club together)

      I agree that no new legislation is needed. The CE regs don't even say there are certain pass limits, they just say that you shall not interfere. There are published guidelines to test to, but no guarantee that meeting the guidelines meets the directive.

      I think that maybe Ofcom wants new legislation to make this non-compliance OK.

    2. Shadowthrone

      PLAs on BT Vision - BT not to blame for issues with the kit.


      Why have they not prosecuted BT for their crap kit? I guess the same applies to Phorm fiasco where the big & wealthy businesses somehow get different rules applied...


      Just for the record BT do not make the Powerline adaptors they supply, they are made a company call Comtrend; BT just supply them. So if any prosecution were to be made with regards to the behaviour of the equipment it would be Comtrend who's adaptor's BT supply in good faith.

      To use a recent "equipment based issue" as an example.....The accelerator problems with a particular model of Toyota recently; any claims that arose due to the fault were aimed at Toyota NOT the dealership who sold the vehicle. Again, for the simply fact the dealership supplied the equipment (a car in this case) in good faith.

      BT has done a LOT of bad things in it's time and quite a few issues can be laid squarely at their feet. However, in this case it is not BT's fault they are just the supplier. Speaking as someone who has, in the past, had to support the Comtrend PLAs in the past while working for BT; I can honestly say they are a pain in the ass anyway and much cursed by BT Staff who have/had to support them.

      1. Anonymous Coward
        Thumb Down


        How are BT blameless? If they know that, as someone above puts it, the equipment pisses all over the airwaves, they are guilty - more so than the manufacturers, since they are supplying the kit and encouraging its use.

        Having said that, OFCOM have a lot to answer for - what are they there for if they can't deal with a problem like this?

      2. TeeCee Gold badge

        Yes of course.

        Your car analogy is entirely about face. In the vast majority of cases, the onus of rectifying a fault with supplied goods rests with the vendor. In the case of cars, that's the dealer. The Toyota issue is a special case as a mandated manufacturer safety recall.

        This principle (bar the recall) applies elsewhere. If you have a problem with anything you've been sold, it's down to the vendor to sort it out. They may well then go on to reclaim from the supplier of the product, but whether or not that happens and the outcome of same does not affect their liability to you.

        This Powerline business is interesting though. IANAL, but I have a sneaking suspicion that if *you* are using something causing interference on reserved bands, then *you* are liable!

        Either way, if you were to take your Powerline plugs back to BT on the grounds that they were faulty (causing interference) BT are obliged to either refund you or replace them with working alternatives (and which one of these approaches is taken is *your* call not theirs). If they turn around and say "fuck off, it's Comtrend's fault", then get thee to Trading Standards sharpish. Whether Comtrend would end up being prosecuted would depend very much on whether the kit actually complies with the standards stamped on it.

    3. Justabloke 1

      title here

      "Well because there is money involved, and Ofcom appear to have been bitten by the Thatcher view that making money off radio use trumps almost everything."

      Yeah, bloody thatcher, she's to blame for everything! I stubbed my toe this morning, I swear she moved the door jamb just as I was going through.


  5. Anonymous Coward

    Bandwidth vs Wavelength

    "PNL equipment, unlike Wi-Fi, doesn't restrict itself to a single frequency but splatters its message across the whole wavelength."

    A certain frequency f is equivalent to a certain wavelength L:

    L=c/f (with c= 300.000km/s)

    So you could say they use many significantly different wavelengths corresponding to the large *band* of frequencies they use. Maybe you have an EE prof proofreading this kind of texts.

    1. Anonymous Coward
      Anonymous Coward


      s/whole wavelength/whole bandwidth/

      1. Anonymous Coward
        Anonymous Coward


        [Exactly again to make the system happy.]

  6. Anonymous Coward

    Ahh... science

    "technology will probably solve the problem"

    I find it odd that this phrase seems to be coming up. Such as the goal incident yesterday "we need technology". Rather vague isn't it?

    Go science!

  7. Anonymous Coward
    Jobs Halo


    Modern planes will still be affected will they....rubbish...They just arn't flying them right.

    1. DavCrav

      I can imagine it though...

      "Roger, tower, I will head on a bearing of CZZZZZRT at CZZZZRT feet. Confirm, over."

  8. Anonymous Coward
    Anonymous Coward

    Wireless mice

    I tried the 200Mbs AV range and all the wireless mice and trackballs in the house stopped working! Needless to say I took the stuff back and laid a cable instead.

    1. Nipsirc

      @Anon Coward - Wireless Mice...

      Not sure how having a big poo will help...

  9. Anonymous Coward
    Anonymous Coward

    So you make powerline quick quick yes?

    Part of the cause might be that the manufacturers think "Hey, it's just wires, right? No need to test for radio wave interference, right? More spectrum for us!" and then proceed to dump as much high-frequency power into the wires as possible. And perhaps ofcom too, as it refused to acknowledge the problem at first, driving the HAM guys to lots of costs.

    The usual rule is that those consumer things are expected to take any interference they pick up but aren't allowed to generate any interference for others. They evidently fail badly at the latter. Frankly, I think it beggars belief that the things are still allowed on the market.

    I'm not a HAM, Shirley.

  10. Anonymous Coward

    BT Vision say "we want", BT VDSL2 people say "we do not want"

    Poor old BT. Their BT Vision folks want this powerline stuff because it "simplifies home networking" and BT Vision is management's Great White Hope to recover the money they've poured down the drain in disaster areas like BT Global Services and BT's much delayed much overhyped 21CN, whose cost savings on the voice side now look like they'll stay as slideware because 21CN voice deployment is "suspended".

    BT's high speed DSL folks don't want anyone to have powerline because once it gets critical mass it wipes out the possibility of high speed DSL pretty much forever, which would leave BT either deploying FTTP (and they don't want that) or leaving the high speed market to cable (and they don't want that). Ouch.

    When I tried it for a few weeks, powerline networking around my house worked about as well as you'd expect if you attempted to transmit Ethernet frames on an interference-prone network without error correction. Lots of stalls while TCP recovers, occasional application-visible errors for stuff using UDP. Allegedly the silicon has improved since then, and now includes retries and error recovery without leaving that kind of thing to higher layers.

    How any of this powerline kit gets CE approval in any country where CE approval is required is an interesting question.

    1. Fred Bloggs 94

      CE approval

      How does it get CE approval?

      Well you self-certificate it and put a CE stamp on the box - hey presto, no-one queries it.


      1. Roger Greenwood

        Far east manufacturers

        Stamp CE on it to ensure it gets Chucked [off the boat in] Europe. True.

  11. Roger Greenwood

    UK Enforcement Authority

    would appear to be trading standards, not Ofcom who go after operators. This applies to all sorts of domestic and industrial goods, but if it doesn't kill people, or affect a lot of people, they seem to have better things to do. Unscrupulous manufacturers and importers take note :- UK is an easy target for crap kit. Oh, you already knew that? Well carry on then.

    (Disclosure - I have a UK amateur license).

  12. dwarmstr

    much more than amateurs "down there"

    "Existing PLN equipment operates between 2MHz and 30MHz - right at the bottom of the dial. The only things down there are the amateurs, who've been complaining for a while now, and a few vertical users who don't operate near the homes where PNL is being deployed"

    And long-distance over-ocean aircraft, international broadcasters, many federal agencies, the military, shore-to-ship comms, etc.-- PLN affects it all. Having much higher frequencies involved is a mixed bag; using them and dropping the under 30MHz spectrum would keep intact the world-wide nature of the shortwave; but higher frequencies would radiate better out of the power line wires. A better approach is to drop the whole thing and stick to technologies that don't radiate outside of prescribed frequencies.

  13. Mage Silver badge
    Thumb Up


    Another good overview

    I've added it to the previous coverage here

  14. copsewood

    mains cabling needs to be designed for comms

    Once the cost of chip + transformer + TCP/IP stack falls to a few pence, just about anything that connects to the mains as with every lightswitch or bulb will be manufactured with a net connection, communicating over the mains power it needs. This enables all kinds of smart energy efficient electrical room environment and device control. Probably won't happen if it needs seperate comms cabling, though it might just using WiFi. But if the mains power is also the comms channel such devices should just work and communicate amongst themselves once they are given a mains connection given suitable standards and software.

    Once your mains cabling is designed to communicate information as well as power higher comms speeds become possible with less interference. Interference will still be a problem with older buildings until rewired though, though eventually everything will be upgraded as with flaky rubber covered mains cables and 3 pin round hole plugs.

    1. Anonymous Coward
      Anonymous Coward

      Yes, no, maybe, rather not actually, pull the other one

      Yes, it would be swell, and I'd probably favour it over wifi. Except that no, it makes using the device when you *don't* want it networked rather difficult. Not up to the manufacturer to decide what to actually put on the network (as opposed to making possible to network). I really don't want my fridge to broadcast to the world just what's going moldy in there, or whatever noble cause they'll tout next, whether by wifi or by power wiring turned aerial. But this sort of utopian's wet dream is really besides the point here. The problem is that the current powerline kit cause interference up the yin yang and for that they should simply be taken off the market.

      Proposing to make sure every house's wiring to be isolated so it no longer act as aerial is so spectacularly impractical that you might as well standardise a new socket with power and some network (say, ethernet) and mandate all new installations be delivered wired up for power AND network on each and every socket. No bets on the chances of either happening.

      1. copsewood

        Yes, it would be swell and I'd probably favour it ...

        Current power line equipment is what it is: inherently interference noisy and giving flexibility and convenience to home networking that otherwise doesn't yet exist. No harm though in considering in advance of this development what wiring standards should look like if the power wiring were designed for communications rather than retro fitted with comms capabilities. Certainly upgrading existing installations to new wiring standards will take a few decades after the new standards stabilise - I was pulling obsolete rubber covered mains cabling out of my first house 25 years after it had been replaced by the current PVC insulated standard.

        As to device security, the migration to IPV6 may give enough addresses to avoid NAT, but it sure isn't going to make firewalling obsolete. Should a lightswitch or fridge once installed advertise itself on the LAN ? Probably, but only enough so that someone who knows the unique password labelled on the back of the device can connect to it using a web browser to choose what it should do. If and when the economics suggested (transformer, chip and TCP/IP stack all cost a few pence) becomes a reality these concepts are no longer utopian, so it's better to start considering the security and cabling or wireless distribution issues beforehand. Would it cost very much more to string a pair of optic fibres into standard mains cable making this upwards compatible with existing installations ?

    2. Captain Thyratron

      Use it for what it's for.

      The power grid is designed to be a power grid. This is quite at odds with being a computer network. The frequency response of every part of it is focused on the efficient transmission of low audio-frequency waveforms; you just don't get to do that *and* effectively transmit signals in the tens of megahertz range with the same hardware. It ain't the right tool for the job of data transmission, and making it the right tool for the job would probably just make it more expensive and less suitable for its intended purpose.

      Water goes through water lines. Gas goes through gas lines. Power goes through power lines. Communications go through communications networks. We do it that way because it works better that way.

  15. Gnomalarta


    end in.

  16. Anonymous Coward
    Anonymous Coward


    What can I say ?

    O£COM still considers that PLT does not use radio waves to operate !

    Maybe they are correct.

    The RSGB has been trying for years to get some action on this, maybe the report will influence things.

    I remain unconvinced that a regulatory organisation that is more interested in making money from spectrum sales is going to be of any use.

    The RSGB explanation of the problem is available to read below.

  17. Hardware Hack

    EMC regs

    In Europe, CE is a self certification but you had better be prepared to show your evidence. For equipment in the home, the relevant standard is EN55022B. All that should have to happen is that someone complains to the appropriate authority and force the manufacturer to provide the evidence.

    As we have cartloads of equipment in every household, it seems, that meet this standard and NOT interfering with world + dog, then if this equipment met the standard, it would also not cause interference.

    This standard is the harmonised standard compatible with FCC part 15B and as someone who has had to get through both (and some other aerospace standards) it's a bitch.

    Does the powerline equipment manufacturer have guidelines on usage? (the usual weasel way out). The length of powerline, it's physical shape, the material (the velocity of communication is NOT the speed of light in copper or aluminium sheathed cable) all cause the effective radiation to differ.

    On the bandwidth comment, the rule is simple: The more data you wish to pump, the wider the bandwidth required for a given bit error rate ( or S/S+N if you prefer).

    Spalttering the spectrum such that it causes (in the words of the standard) 'harmful interference' invalidates the CE mark in Europe and should be dealt with as such - of course, we don't want to annoy all those people selling the stuff and generating all that lovely VAT, do we.

    Grenade for the crap kit.

    1. Anonymous Coward

      Channel Capacity

      Read up on the Great Shannon. Bandwidth and SNR affect maximum possible bitrate. If you have extremely good SNR, you need less Bandwidth:

      Bitrate= BW*log2(1+SNR)

    2. Anonymous Coward

      You're having a laugh surely?

      "In Europe, CE is a self certification but you had better be prepared to show your evidence."

      Dream on. Most consumer electronics these days are available for less than 2 years before a new model comes out. By the time the local country regulator (if they give a shit, most don't) is made aware of an issue, checks it and then jumps through all the legal hoops the product is EOL.

      The CE mark is bollox, it always has been and it always will be. Thats the nature of EU rules - and specifically the enforcement of said "rules". CE rules rely on countries adhering to the rules which isn't something you will find happening in most EU nations.

  18. BristolBachelor Gold badge

    Won't help Ofcom's DAB obsession

    "Perhaps the regulator is hoping that FM interference will shift more users onto DAB "

    Maybe, but you see the only reason that they want to do that, is to sell all the bandwidth. Who in their right minds is going to pay for that bandwidth if it is full of s**t from unlicensed PLN kit?

  19. Anonymous Coward
    Thumb Down

    Wot, only bearded hams complain?

    Those of us who are non-bearded lady hams have issues with this sort of noisy tech as well.

  20. Anonymous Coward
    Anonymous Coward

    Interesting info

  21. Dodgy Geezer Silver badge

    I'm 52, you know...

    and I remember the fiasco with CB in the 1980s. It broadcast right on top of the allocated model aircraft slot at 27Mhz. Obviously causing much damage and danger.

    The Home Office Radio Regulatory Department (as was) held up their hands in horror and said "We didn't know it would do that.".

    Thirty years on, their children have obviously reached the same position in OFCOM....

    1. This post has been deleted by its author

  22. Refugee from Windows
    Thumb Down

    Once your mains cabling is designed to communicate ...

    Of course as well as an unbalanced, unscreened and multiple path cable system can be. Which isn't very good at all. Why do you think power distribution uses 50Hz rather than 400Hz which would make transformers rather smaller? Something to do with interference to telephone and telegraph lines so it's not a new issue.

    Without my Radio 4 fix I'd be lost (or rather uninformed) and I'm 'eckers like buying a DAB radio when I've a perfectly good radio or two around the place.

    1. Jim Bob


      Interference is a minor reason for using 50/60Hz rather than 400Hz for large power distribution. 400Hz is limted to applications where size or weight limitations make the additional loses tolerable, eg aircraft.

  23. Anonymous Coward


    Useless, overpaid twats. The IEE (now IET) have been raising this as an issue for the best part of a decade... their solution is to pay PA Consulting £100,000s to produce a report...

  24. Anonymous Coward
    Anonymous Coward

    So now...

    ...we've all got to switch off electrical items when the plane is taking off - whether we're on it or not.

  25. Anonymous Coward
    Anonymous Coward


    Kitties on the wall :D

    ... er...yeah, PLN interferes with stuff. Nicely shown.

  26. Martin 71 Silver badge


    Wouldn't it be easier to just point out that PLN kit, by definition, broadcasts without a license, advertise the fact widely, and later, aggressively prosecute anyone caught using it? The fines could pay for say, installation of wired networking :-)

    1. This post has been deleted by its author

      1. kyndair

        Yes it is a title

        Complying with EN 55022 gives a presumption of conformity to the EMC directive as it is what is known as a harmonised standard. That is it has been published in the Official Journal of the European Union (a list can be found here

        If the authorities (BERR & Trading Standards) wanted the vendor to show they were supplying products that comply it is this they would look for first and if BT could not produce it or the authorities decided to be proactive (as if) they could show via independent testing that it failed and then they could order its recall from consumers with BT et al picking up the tab. But they won’t, at least not till everything goes t*ts up.

        Flames because the revolution is coming (to a cinema near you, popcorn extra)

  27. Steve X

    I'm all right, Jack

    So, it's "only hams" that are affected, so it's not an important problem? I hope that arrogance isn't typical of the author's attitude to other people. The whole spectrum is divided up by international agreements, identifying primary and secondary users of each slot. Anyone who is a primary user of a frequency is entitled to use it without interference, whether it's granny listening to the Archers, or a radio ham relaying emergency messages from an earthquake zone.

    If you think given classes of user aren't entitled to protection from your poorly-specified and designed computer comms gear, ask the ITU to remove their allocations. Until then, respect the rules or accept the consequences. Maybe our new ConDem lot can give Ofcom some teeth.

  28. Peter Simpson 1

    Failure in US

    PLC or BPL (Broadband over Power Lines) has failed pretty spectacularly in the US. The combination of Ham opposition, poor data rates and installation and maintenance expenses far higher than DSL or fiber, doomed it.. As was pointed out above, there are only so many bits per second you can push through a wet noodle, and it will require more effort in terms of clever modulation schemes, noise reduction and signal power than using something made for the task, like fiber or (arguably) coaxial cable.

    1. Anonymous Coward


      ...many lazy people can continue to grow fat and sit in front of the TV, paid by the state - in case of PLC.

      You would demand too much of these weak members of society to dig up the street and lay proper comms fiber. PLC technology is ideal for European (including British) socialism. Never mind PLC fscks up the spectrum.

      As long as TV is not affected....

  29. Dazed and Confused


    A couple of years ago a couple of BT engineers knocked on our front door while I was off in some other corner of the world. The wife answered to be greeted with.

    "We're investigating interference in the area and there seems to be a lot of interference emanating from your house madam".

    At which point the wife starts to get very worried since my study looks like a cross between Mission control and a mad scientist's lab and she did fancy being made to go through everything there to work out what was causing the problem.

    Fortunately he then looked at his equipment and pointed to the other corner of the house and said "It seems to be coming from over there" pointing at the living room. It turned out that the power supply for the PVR was up the creak.

    Now I don't know if it is still the case but I know the GPO used to be able to prosecute you for causing interference. This didn't get that far since the Mrs was happy to just disconnect the PVR till I got home and bought a new power supply. But there was a definite implication that causing the level of interference wasn't acceptable.

  30. Anonymous Coward
    Anonymous Coward

    There aren't any standards for PLN right now.

    Yes, you heard me - none.

    The BSI have been pushing for one for years (decades?) now, and the EC have finally given the go-ahead to the BSI to create one.

    OFCOM have had absolutely nothing to do with any of this - they've been steadfastly ignoring the issue.

    - Incidentally, the average British home is exactly the worst possible situation for PLN technology, as a ring main is a pretty good loop antenna. It wouldn't surprise me if the new standard specifically precludes this kind of usage.

    (Anon as there aren't many places that have examined the radiated interference of PLN systems, so it would be a bit too obvious otherwise.)

  31. Anonymous Coward
    Anonymous Coward

    Not only

    Re;- Once your mains cabling is designed to communicate.

    People went to 50/60 hz because the transformer laminations were less lossy at the time. Now 400Hz would be much preferred to reduce the transformer costs. Having been one of the engineers who designed for data transmission over the household wiring, I can assure you that whether it works or not is an extremely pot luck operation. Blocks of flats are a nightmare as the signals go wherever they feel like. I've seen a set up where the propagation range was less than 2M, all dependent upon the characteristics of the cable and local connections. Rather like ADSL, where you are also frequently dependent upon the age of the cable. It is extremely enlightening to run even a simple Spice model of household wiring to see where things actually go! There should however, be a requirement to prevent the transmissions from being bidirectionally propagated. Some years ago, the MOD were totally bemused to realise that a telephone cable could radiate longitudinally so I'm not surprised that OFCOM haven't much of a clue.

    1. Jim Bob

      Like to see the figures...

      Just how close are modern 400Hz transformers to 50/60Hz in terms of efficiency? A efficiency drop of 1% on a 1000MVA transformer is 10MVA. How many energy companies will accept throwing away 10,000kWh of revenue (per hour per transformer) just cos the cap ex was a little bit lower?

    2. John Savard

      400 Hz

      I do know that many of the old mainframe computers, and also some avionics, distributed power as 400 Hz alternating current. The use of alternating current, of course, was for the same reason as its general use in the electrical power system - so that voltage could easily be stepped up and then back down again, allowing the need for really thick wires to handle lots of current to be avoided. The higher frequency was so that they could get by with smaller transformers and smaller capacitors in the power supplies that finally converted the AC power to the DC power that the electronics actually used.

  32. peter_dtm

    Ignorant & arrogant - must be a politician

    *just hams*

    oh & the military

    & all sorts of search & rescue

    & lots of airline GLOBAL comms systems

    & radio astronomy

    & ship to shore

    ( military & hams btw are normally the 1st & only working comms in disaster zones)

    And PLT is rubish technology on so many counts

  33. JeffyPooh

    Wires strung between poles...

    They're called antennas. They radiate.

    Sending broadband data over power lines is Satan's own handiwork. Pure evil. And a sign of corruption because the government is responsible to protect the electromagnetic spectrum from such stupid ideas.

  34. Anonymous Coward

    "the GPO used to be able to prosecute you for causing interference."

    Something like that.

    However, in line with the company's policy of continuous product and service improvement, BT have apparently "let go" of most of their experienced Special Faults Investigation folks who would have dealt with cases like this causing interference with DSL services.

    These days, if swapping kit or wiring doesn't fix it in a couple of attempts, it may well not get fixed, just marked as "not suitable for broadband". Even if there are folks with the skills and experience to fix a problem, they're often not allowed to spend the time it takes.

    That'll work well if/when VDSL gets more widely deployed. Not. It's going to be bad enough as the crosstalk goes up as ADSL2+ gets more widely deployed.

  35. Number6

    Going the other way

    Given that PLN is probably immune to it so the issue will never arise, but I do wonder what would happen if PLN got clobbered by the local radio amateur chatting to his mates around the globe.

    For the record, we don't all have beards.

    1. This post has been deleted by its author

  36. Henry Wertz 1 Gold badge

    Whinging not a fail

    "Whinging about your ham radio not working? Fail."

    Not a fail at all. Fact of the matter is, powerlines are unshielded, are not meant for long-range data transmission, and have been shown to blast massive amounts of noise all over the spectrum. The powerline guys (who are after all the ones that will make all the money) insist it's not a problem, despite numerous demonstrations that it is. This will also interfere with some television, and also could easily interfere with cable TV as well. They are planning to blast noise over 100s of mhz of spectrum, some set aside for public use, and some that is licensed. Nobody else is permitted to do this, why should the power companies be given a free pass to?

  37. Mage Silver badge

    CE PSUs!

    Here is a CE PSU sold by Maplin.

    It's mysteriously missing all the filter parts that make it CE compliant.

    It stops Homeplug and Comthingy Power networking

    two chokes missing and jumpered

    five capacitors missing


  38. G7VZY

    Interesting reading..

    Well, the think that leaps out at me is in appendix I section 7 of the report, where the chaps at PA consulting cheerfully mention they received the interfernce from their single reference PLT installation ~70m away, re-radiated from the overhead feedlines. Essentially, in a built up area, radio use would become impossible if most houses had something like this, as like rats in the drains you'd never be far from either one or the next.

    I really can't help but believe that either money talks, and someone profits a lot from looking the other way, or more sinisterly there is a hidden agenda to discourage folk from listening to anything other than strong local radio stations, smatterings of the sort of behaviour we used to pity the eastern bloc countries for.

    For what its worth, I understand the Comtrend kit was CE approved, based on inspection of a technical construction file, rather than laboratory testing, and granted by a Spanish approvals house, using (or mis-using) levels taken from a draft copy of a PLT standard that had been withdrawn as unworkable without ever being ratified.

    Oh dear, here I go again.


    PS A big reason there aren't complaints of reception from greater distances is dificulty in being sure where it is coming from until close. If anyone wants to build a PLT network with a filter that is switched in and then bypassed with some recognisable code (sending "P_L_T" in morse perhaps) real range tests of an individual unit would then be possible by listening to the modulated noise.

  39. gimbal

    Not even a necessary technology

    I'm one to side with the folks scratching their heads that this kind of equipment is even allowed, on the market, given the interference it clearly produces. This novel powerline-network technology isn't even necessary - use ordinary network cable, or fiber if you're really feeling speedy.

    If the manufacturers can't figure out how to make it work without the bad bleed-over, pull it. It's that simple.

    Otherwise, we may as well deregulate every kind of RF-producing device. Microwave ovens blocking cell phone signals for a whole city block, for instance - my, that would be fun, as long as we're getting payed for it!

  40. M Gale

    Hang on...

    "PLN equipment, unlike Wi-Fi, doesn't restrict itself to a single frequency but splatters its message across the whole wavelength. This gives great capacity at the cost of widespread interference."

    I'm pretty sure that one part of of the "N" standard for wifi was to make it spread-spectrum? That is, rather than choosing a particular frequency, it splatters itself all over the band? So that, you know, noise on one frequency (like a leaky microwave oven) doesn't ruin the performance of your network while you watch a cat hitting a keyboard?

    I'm sure the various beardy and non-beardy HAMs here will tell me why I'm wrong.

  41. Anonymous Coward


    As a bearded old ham, I'm going to just build me a couple of dirty wideband spark gap transmitters to cover the PLN spectrum and leave them running when I'm not on the air. This should p*ss all the PLN users as their data transfer rates go down the toilet!

  42. Christian Berger

    < 30MHz the only usable radio range for broadcasting

    Unfortunately higher frequencies are absolutely unsuitable for broadcasting as the signal doesn't follow the earths curvature. Just look at the VHF-Bands for example:

    They only work sporadically for short amounts of time.

    Here's one of the videos:

    The transmitter was in Iran, the reciever in the netherlands, yet the quality is bad.

  43. Robin Bradshaw

    Homeplug wardriving???

    Since these powerline networking things appear to be splattering interference all over the place is it possible to sniff the data being transmitted from a distance??

    I suspect a demonstration of snooping on a neighbours web surfing would go some way towards curbing the publics enthusiasm for such devices.

    1. Richard 12 Silver badge

      You don't even need to bother doing that.

      The PLN systems aren't affected much by modern electricity meters, and there's bugger all filtering anywhere until you're back at the local substation.

      So if you want to join their network - just plug in a compatible PLN anywhere on the same phase from the same local substation. That's generally most of the street, if not a third of an entire housing estate.

      You'll join their network and can do whatever you please. PLN makes WEP WiFi look secure.

  44. Anonymous Coward

    bearded geeks

    Be careful who you call bearded geeks in the Ham radio community! yes they are not pleased at all.

    However you forgot to mention HEALTH MONITORING EQUIPMENT both in Hospitals and in Care Homes, emergency pagers etc etc

    So no doubt you might be a tad unhappy when your ipod stops or your laptop fails to connect to wi-fi broadband, apart from Radio4 and the Archers or your 'Granny' can't get the help she so desperately needs!

    There are many many 'ham radio' members in BT, SKY broadcasting, Gov listening stations Marine, Aviation and most all radio communication industries you can think of - even Ofcom, so might be wise to lay off the wise cracks - you never know what interference might be generated!

  45. Lamont Cranston
    Black Helicopters

    I live next to airport, and love Radio 4,

    so have to conclude that the young man in Maplin who wanted to sell me a powerline kit @ 200Mbs (rather than the cheaper 54Mbs), was actually trying to kill me (or at least make me miserable.

    Nevermind that my broadband connection struggles to get over 2Mbs.

  46. Tom 64

    Civil aviation threat? Please

    I think that guy should take his little handheld radio set, jump out of an airplane from 10,000 feet, then test to see if there is interference from PLN devices in the CA band while he's free-falling..

    1. Anonymous Coward
      Anonymous Coward

      I think you need to read the report.... it is clearly stated there that the threat to aviation is more to do with glideslope and localiser frequencies in the face of gigabit PLT interference that can reach 300MHz..

      If you're trying to receive a weak signal as you fly over houses under the airport approach paths, then it becomes a problem rapidly. 300 ton aircraft wandering off course at low altitude is not recommended.

  47. John Savard


    I thought that the British Post Office could be trusted to voluntarily avoid interfering with aviation and the BBC, even in the absence of specific legislation, what with it being an arm of the government and all.

    Evidently, your country must have looked enviously at the success of the Yanks with this futuristic Internet stuff, and it decided to let some private enterprise in. That could be your problem right there.

    But this Ofcom of which you speak is Britain's telecommunications regulator. Does it lack authority to regulate that power companies acting as Internet providers not go around jamming the airwaves? Or perhaps it is not to Ofcom that ITV must hearken to get its licences to operate its broadcasting stations?

  48. Roland6 Silver badge
    Black Helicopters

    Know any terrorists :)

    From the various threads on this topic, there seems to be a question mark over the maximum distance between paired powerline devices and whether they really can interfere with aircraft communications.

    It would seem that the distance query could be quite quickly be addressed by an experiment on a university campus, ideally one with on-campus halls of residence.

    The aircraft communications query can be resolved by setting up a PLT network within the boundaries of a small airfield (ie. somewhere with few air movements and to which it is relatively easy to liaise with the 'tower') and do similar to the distance experiment.

  49. Version 1.0 Silver badge

    But I thought ....

    ... you folks were all "allergic" to cell-phone radiation and Wi-Fi network signals ... is this some sort of "better" radiation? Tin-Foil underwear anyone?

  50. steogede

    What has Radio 4 done to deserve this?

    If it weren't bad enough that every personal transmitter in existence seems to be tuned to the same frequency as Radio 4 (in my region) - now they're going to kill it entirely. I suppose they've got to do something if they want to sell DAB radios.

  51. Anonymous Coward

    "this Ofcom of which you speak is Britain's telecommunications regulator."

    No, it is *called* the regulator, but that is only what it is called (and what its staff are paid to do). It doesn't actually *do* any regulating unless it is absolutely forced to. Here is an example where it needs to be absolutely forced to do something. Any suggestions as to how?

  52. Anonymous Coward
    Anonymous Coward


    As has been pointed out, O£COM has concluded that PLT/BPL is not a radio transmission and so cannot be enforced by the various wireless telegraphy acts.

    Some of the kit being sold has got amateur-band notching, large amounts of the new kit being imported do not have this notching. Still larger amounts of cheap PC power supplies do not have the filter components installed.

    The RSGB is currently attempting a legal challenge to OFCOM about the subject, their attitude can be read here:

    Which also contains data on the power levels transmitted by the devices.

    While transmitting high power will swamp the devices and render them silent for a while. it does not do much to quell the interference, which at times leads to a meter reading of S5+ on the lower HF bands.

  53. Anonymous Coward

    Just ban it

    Just ban the use of power-line networking.

    If it isn't shielded there WILL be all kinds of interference. Stop this shit before more money is wasted on it and lay FIBER.

    In other words FIX and update THE INFRASTRUCTURE and there is no need for band aids like power-line networking!

  54. Herby

    What about the BBC World service?

    While I suspect that PLC (we call it BPL here in the USA) will interfere with just about anything that thinks it is a radio. It is a VERY wideband junk that uses the house wiring as an antenna. The proponents may not say that, but that's what it is.

    From what I've seen, it works really neat "across the room" (pay no attention to the man behind the curtain), but then when you scale it up and get LOTS of users playing around with it (it doesn't take many) and do it over a wide area, it turns to s**t real quick.

    Somebody ought to take the example here in the USA where a really big pilot program just closed its doors and went quiet after finding out that it didn't sell too well, and didn't perform too well either. Between poor customer acceptance (I wouldn't want to be at the call center for complaints), bad data rates, high cost to users, AND the interference problem it will die. Don't even try to invest in this boondoggle you WILL lose money.

    Bottom line: WHY BOTHER. It ain't broadband, and it ain't over power line!

  55. Anonymous Coward
    Anonymous Coward

    Radiation hazard

    Whilst I applaud articles that raise awareness of the real problems that PLT devices are causing I do not believe that it is helpful or constructive to state or even imply that those currently affected by these devices are in some way less important than other users of the radio spectrum who will suffer in the future. You have employed language that appears to single out amateur radio users and short wave listeners as somehow unimportant or, at the very least, less important than other users.

    Clearly safety-critical and national security uses of the spectrum must be given top priority. Having said that, the rest of us must surely be treated equally fairly when it comes to the protection of our radio spectrum? Inferring that amateur radio users are less important than Radio 4 listeners, for instance, appears to show a significant and regrettable ignorance of what amateur radio is about. Is it ignorance or are you being disingenuous?

    It would have been helpful to mention that Amateur radio is in fact leading the fight against devices which do not comply with the relevant EMC Directives. Your article would have been fairer had you altered the ‘spin’ to emphasise this point.

    I would just make this prediction: PLT devices that meet the current relevant EMC Directives will never be available at a competitive price. It simply cannot be done cheaply enough. We will all, every one of us, suffer as a result of the continued roll-out of these dreadful devices. The EMC Directives are there to protect all our interests and we need strong government action to ensure that they are implemented properly.

    Finally, I would like to say that when a significant civil emergency occurs, and trust me there will be one, we will all have cause to be very grateful to the amateur radio community. Every single UK amateur radio licensee has the duty to pass messages on behalf of User Services such as Police, Fire and Ambulance when asked to do so. You can rely upon the necessary equipment being available when required. In addition, organisations around the globe such as the UK's Raynet will ensure that key national, indeed worldwide, communications are maintained. Be thankful they are there.

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