back to article BBC engineers see PLT knocking out DAB

Recent experiments carried out by the BBC demonstrate how power-line networking can interfere with FM radio and knock out DAB entirely, but only for those who get a decent data rate. The new study was commissioned by the BBC and authored by one current and one former BBC engineer. The study examines transmissions coming off …

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  1. Loyal Commenter Silver badge
    Troll

    Hmmm, I wonder which is more useful?

    PLT or DAB?

    1. Luther Blissett

      I wonder which is more useful?

      Ofcom or BBC?

    2. Bob H
      Paris Hilton

      Various evils

      Neither technology is fantastic really, but quite frankly I would rather do away with DAB. A 20 year old technology with limited take up, poor performance and no strategy for upgrade? Fab. At least Powerline Networking has a roadmap!

      DAB has sold about a million units, I think, of those no one knows how many people are actually using the DAB part. The technology is ancient and uses old error correction techniques, simple modulation and a simple codec. Yet, because it is quite unique and hasn't a large take-up (worldwide) it still costs a fortune to buy the components. Overall it would be cheaper for everyone to abandon it, just transmit some public service channels for a few more years (5?) and move to a better system before the forecast sale of +50million UK digital radios really kicks off.

      Replace it with DVB-T2 which can have profiles for very robust mobile reception, could achieve national coverage quickly and the components would be at commodity pricing instantly because half a dozen other countries are using (or planning on using) it for their TV delivery. It would also be compatible with UK Freeview HD products and thus wouldn't involve duplication of equipment for those that had a Freeview HD product.

      Although I do appreciate that channels might be duplicated because they are already broadcast on DTT but not in a mode which is mobile and so broadcasting them on DTT would allow them to be broadcast in HE-AAC for good quality, with highly resilient error correction for in-door reception and a decent timing mode to allow for reliable mobile reception.

      Yes, sorry those who already have a DAB radio, but for most people DAB sucks.

      Paris, because she's always up for something new.

      1. Richard Taylor 2
        Thumb Down

        Figures

        You might wish to check your figures. Leaving technical issues aside, in 2010 alone about 2M units were sold in the UK (source http://www.zdnet.co.uk/blogs/jacks-blog-10017212/dab-radios-declining-sales-eforum-revisited-10022187/)

  2. Anonymous Coward
    Anonymous Coward

    One man and his hobby.

    Would that be Simon Quinlank? Mine's a flask of weak lemon drink.

    1. Anonymous Coward
      Thumb Up

      Weak lemon drink

      Drink it! Drink it now!

    2. Rob Beard
      Thumb Up

      You're not a hobby horse...

      ...you're a hobby Lion!

      I dunno, sounds like the Beeb want the Moon on a stick.

      Mine's the one with Alan Milk Carton Body in the pocket :-)

      Rob

  3. Anonymous Coward
    Anonymous Coward

    FM vs DAB

    "FM radio can scale back from stereo to mono when necessary, and can cope with quite a bit of interference before becoming unintelligible"

    This, my friends, is why I won't be switching to DAB any time soon.

    1. Anonymous Coward
      Anonymous Coward

      Re: Fm vs DAB

      "DAB is particularly vulnerable to interference as it either works or it doesn't, with just a small change in signal strength flipping it between the two. FM radio can scale back from stereo to mono when necessary, and can cope with quite a bit of interference before becoming unintelligible – though listeners may decide to tune out before that happens."

      I was under the impression that, although the jump from "working well" to "not working at all" for DAB was swift, it happened at a comparable signal level to when FM would drop from "fuzzy mono" to "bugger all".

      In other words, for a comparable weak signal strength, when FM was only managing mono output, DAB would still be giving you clear stereo.

      Personally, I've never understood all the DAB hate that exists - maybe cheap DAB radios are worse than cheap FM radios...

      1. handle

        DAB hate

        The problem is the bit rate. It has been wound down too far in order to squeeze in more channels at the expense of audio quality. In some circumstances it will give a clear signal where FM fails, but the clear signal suffers from compression artifacts which are not present on FM (and to a much lesser extent on radio channels on DTT [Freeview] because the bit rate is higher and the compression more sophisticated). So the best DAB is much worse than the best FM.

        1. Jim Morrow

          the quality of the message matters too

          apart from radio 3 there's essentially nothing on any uk radio that justifies or needs a high bit rate. if the content is shite it makes no difference what the bit rate is: it's just not worth listening to.

        2. Anonymous Coward
          Anonymous Coward

          "The problem is the bit rate."

          I agree. 64kbps on some channels. Welcome to 1995.

      2. MrT

        There are no cheap DAB radios...

        ...or at least none in the same price bracket as a cheap FM radio - eBay has FM sets for £1.25, including headphones, but DAB seems to kick off at about £15 (seen at Tesco), and in both cases decent kit is a *lot* more than that. Some of the hate might be because of the cost...

        Mind you, I like DAB for what it gives - I've a Pure One Elite in the kitchen and my car has DAB built-in, and apart from being noticeably, but not by much, quieter compared to FM, listening to DAB is just fine.

  4. Naughtyhorse

    Ofcom is still digesting the research and will let us know when it has....

    found enough cash down the back of the sofa to pay back the _massive_ bung they clearly got to look the other way when PLT sneaked in.

  5. Anonymous Coward
    Dead Vulture

    ilk

    "only interfered with the kit of radio hams and the like"

    1. Anonymous Coward
      Anonymous Coward

      ilk...

      ..."a group of entities that have common characteristics such that they may be grouped together."

      Wiki

      1. Kubla Cant
        Headmaster

        ilk...

        You may be disappointed to learn that Wikipedia is not entirely reliable.

        "ilk" means "the same", hence "Sir Angus MacSporran of that ilk" means that he is the MacSporran of (the clan) MacSporran.

  6. Anonymous Coward
    Thumb Down

    F*** Amateur Radio

    This makes me sad. I was into amateur radio as a child, it was great to learn basic electronics on.

    Power line telecommunications - that's just broadcasting on unshielded antennas.

    What we need is a magnitude 6 earthquake in the middle of London - lose all our mobile phone towers and cabled communications - then see how little respect everyone continues to have for amateur radio enthusiasts.

    1. TeeCee Gold badge
      Grenade

      Re: F*** Amateur Radio.

      So, zero respect and an irrelevance for the next few millenia at least then?

      1. Kwac
        Thumb Down

        Re: F*** Amateur Radio

        Ask people in places affected by storms, earthquakes tsunamis, terrorism if amateur radio is 'an irrelevance for the next few millenia".

        After the Twin Towers attacks, Japanese earthquakes, Haiti, etc amateur radio was the ONLY form of communication - which is why the pollce & military turned to them.

        Of course, the UK is immune from Lockerbie-type disasters (yes, radio hams were out with the search parties).

        Yup, zero respect, but only from those with their head so far up their a**e they don't realise they can't use their mobile when the battery is flat or the repeater is damaged.

  7. Cameron Colley

    But, but, but...

    Ofcom have already thoroughly tested the devices and found "THERE ARE NO PROBLEMS, NOTHING TO SEE HERE". Surely they weren't lying?

  8. Anonymous Coward
    Anonymous Coward

    Hmmmm show of hands.

    At home, in 2011, who would prefer a radio signal over having the internet/a network connection?

    1. The Alpha Klutz

      you can have both

      If you use WiFi or Ethernet.

      Though I suppose PLT is okay if you get agreement from every house within 500 meters of yours, that they don't mind having their DAB jammed so you can use your internet. I can't really see anyone agreeing to that, even if they do hate DAB.

      1. Richard 22
        Thumb Down

        But you can have both anyway

        I used to use PLT and never noticed any DAB (or FM) reception problems at home (since rearranging things and running cabling to get gigabit ethernet connection I no longer use the PLT kit). I'm guessing it depends on the exact PLT kit used, the state of the wiring and the positioning of the radio, so I don't think there's any need to be alarmist about this.

        1. Anonymous Coward
          Anonymous Coward

          Very particular selection of product used for tests...

          Interestingly, the report seems to go out of its way not to mention which PLT kit it is - except to say that they have chosen ones that go up to 305MHz.

          Anyone who knows anything about powerline home networking technology can tell you it's a pair of Belkin "Gigabit" adapters, using the Gigle chipset (you can recognise the product in the pictures if you know what you are looking for).

          So - they have selected the least deployed chipset of all, one that is renowned among engineers for its poor noise immunity performance (you will find online reviews give poor ratings for bandwidth, it's not only those with technology knowledge), and the only one available to use frequencies above 68MHz (almost all are under 30MHz) and make disturbance to DAB signals. The reviews of these Belkin products were bad enough to make the product quite difficult to find for sale nowadays.

          The claims of radio amateurs that PLT equipment will disturb over 500 metres away are false for any products on the market today (even if ever they could be verified) - whilst I would agree that the old Comtrend products using old DS2 "UPA" chipsets were bad products in their ability to disturb and in performance terms, products applying the HomePlug AV specification without any proprietary extensions (as in the Belkin 1Gbps) do not have issues (unless you are a radio amateur who will tune out of amateur bands to find low level emissions very locally to your special antenna).

          1. Robert E A Harvey
            Coat

            @AC 10:06

            So what are you saying? Someone is having a Gigle?

      2. Oddlegs

        The title is required, and must contain letters and/or digits.

        I use PLT in my house. I also have no problem listening to my DAB radios. Seems like a non-issue to be honest

        1. MrT

          Same here...

          Is this more likely to be a problem affecting network transmissions over HT powerlines, such as the ISP to home link being carried along high-level pylons?

        2. This post has been deleted by its author

          1. Robert E A Harvey

            "only"

            Sadly, long range radio listening on HF has become pointless just as a new generation of software controlled radios was making the hobby innovative again.

            I really miss listening to Strauss from Vienna on 12MHz, and one of the high points of my life was listening to the Bernstein "Ode to Freedom" performance on Deutsche Welle's short wave live coverage.

            http://www.amazon.co.uk/Beethoven-Symphony-Freedom-Bernstein-Berlin/dp/B000001GDR

    2. Naughtyhorse
      FAIL

      on a similar note...

      my car runs like stink on plutonium...

      your kids health??? not my problem mate

  9. Martin Summers Silver badge

    Sheer Poetry

    Something the majority don't want (DAB) knocked out by something Ofcom refused to deal with. The powers that be get their comeuppance in the end :-)

    1. Jolyon

      Want

      Do people actually not want DAB or is it just that people in areas with poor reception don't think it's any use?

      For me it's a tremendous improvement over AM/FM - probably 80% of my media consumption is DAB radio (although the admongers would be less keen to know that 99% of that is advert-free BBC).

      If I couldn't have it, I'd certainly miss it; frankly I'd probably even pay for it.

      1. Robert E A Harvey

        Hate

        DAB is a geriatric solution to a problem that does not exist.

        Originally conceived as a way of automating radio listening so that people did not have to re-tune their car radios as they drove along, or suffer fading from multipath it was also adapted to increase the number of channels available by TDM. But we are not short of FM spectrum, particularly when so many local commercial radio stations have been merged into national conglomerates. And a serious attempt to measure the artistic quality would be very disappointing. Very dissapointing indeed.

        The battery consumption of portables is appalling, and the level of technology required means that cheap radio is impossible. And the abysmal bit rates drive the final nail into the coffin from my point of view.

        Oh, and as early adopters, nay originators, we are lumbered with a system that the rest of the world has moved on from.

        We have internet capacity enough and satellite channels that cover all the stations (although the satellite channels are under-utilised, being fed from the low bit rate DAB channel in too many cases). Our american cousins, for all their failings, have adopted satellite receivers for cars rather than DAB, and we could do the same. On the subject of internet capacity, that could be improved if ISPs put simple caching servers in the exchanges, so that multiple consumers of radio or tv could be given a single feed over the backbone, rather than multiple identical feeds occupying bandwidth.

        And yes, I live in an area which is "marginal" for DAB, but then it is "marginal" for FM, DVT, rdio 5 MW, and broadband as well. If DAB were any good I'd be putting up antennae

        1. Anonymous Coward
          Megaphone

          Re: DAB solves nothing

          I agree - what is the point of DAB? FM serves a purpose - a constant amplitude signal that can easily be tuned into by a phase-locked-loop.

          AM also serves a purpose - dirt cheap receivers.

          Why add DAB to the mix? For one it limits sound quality - secondly it requires complex kit - thirdly it prevents any hobbyists (e.g. children) from ever building their own receiver kit - 4th it makes a LOT of cars/receivers mere industrial waste (radios have to be some of the longest-surviving hardware that continues to be in use, unlike computers which get trashed every 3 years).

          I'm against DAB. Digital video - yes, that makes sense, more channels, great. But FM - I like my car radios, the simplicity of the technology (and it was a fantastically simple but elegant solution for high quality radio reception in challenging conditions - even lightning struggles to disrupt a FM signal).

  10. Andy Neillans
    Boffin

    Factual?

    "Power-line telecommunication (PLT) involves sending radio signals over mains electrical wiring."

    Erm. Radio signals over mains electrical wiring. I think someone needs to revist tech 101. It might be an analogue wave form, but that does not make it a radio signal. Now, one it "broadcasts" from the wire ... thats a different matter ;)

    1. Anonymous Coward
      Anonymous Coward

      It's still a radio signal when it's on waveguides

      These things *are* radios, they're just trying to use your average (completely unsuitable) twin-and-earth wiring as a waveguide, supposedly to avoid broadcasting the radio.

      The tests we did a while back showed that ring mains made from twin-and-earth always turned into pretty good antenna to broadcast, generally pretty detuned so very wideband.

      Radial circuits were ok if you put suitable filtering at each end and properly terminated them, as otherwise everyone on your phase of the supply could listen in - the meter doesn't actually block it, though the substation transformer did.

      So they may well be suited to mainland Europe and the US where ring mains are rare - if you can pursuade everyone to fit a termination block to the end of all their radial wiring and a massive filter at the incomer.

    2. Pypes

      title etc

      I think it's perfectly reasonable to call these radio singnals in the sense that there is not a cat in hells chance that anything in the frequency ranges that PLT uses is going to stay confined to the cable.

      This whole "but it goes down the wire so it isn't radio" is exactly the area of ignorance that the manufactures are seeking to exploit. I'm not saying your wrong, but people who are concerned about the spread of this tech really need to hammer home the fact that these are essentially radio devices, they just happen to share a antenna between them.

  11. Anonymous Coward
    Anonymous Coward

    Finally, a sensible article from Bill Ray

    Thank you Bill for finally writing an article which mentions amateur radio and doesn't take the piss.

    Perhaps now these reports from Ofcom and the BBC have been published, the problem will be taken seriously because despite what Ofcom had hoped, it won't just go away.

  12. Anonymous Coward
    Anonymous Coward

    hmm

    does PLT bugger up digital tv reception as well? I get quite remarkably bad and suspiciously erratic digital tv reception in my new place.

    1. This post has been deleted by its author

  13. Anonymous Coward
    Anonymous Coward

    Description

    "Power-line telecommunication (PLT) involves sending radio signals over mains electrical wiring"

    Can you add a word to that description please? It doesn't send radio signals down the wires as such it sends signals down the wires at the same frequency as radio transmissions. So can you stick the word frequency between "radio" and "signals"?

  14. Christopher Key.
    Megaphone

    Not fit for purpose

    Although a first reading of the EMC directives yields the rather circular statement,

    "The apparatus shall be so constructed that

    equipment shall not generate electromagnetic disturbances exceeding a level allowing radio and telecommunications equipment and other apparatus to operate as intended;

    equipment shall have an adequate level of intrinsic immunity from electromagnetic disturbances to enable it to operate as intended."

    further research shows that there are actually relevant standards (with well defined, quantified limits) to which equipment must adhere. Moreover, OFCOM's own research has show that PLT kit fails to meet these requirements:

    http://www.theregister.co.uk/2011/03/31/ofcom_plt/

    I would suggest that Trading Standards might be more useful, as products have to be EMC compliant to be CE marked, and it is their job to police this.

    I've recently been trying to deal with RF interference in the LW and MW bands knocking out my ADSL connection. OFCOM proved similarly useless and uninterested in this situation, spending a week telling my ISP that I had to pursue this with then (i.e. OFCOM), and telling me that my ISP had to pursue it with them. Eventually, they confessed to my ISP that they were no longer interested in policing interference at these frequencies, and that it was essentially a free-for-all.

    1. Christopher Key.
      Boffin

      Interference with BT Infinity?

      Further research yielded some test results[1] which show that PLT devices transmit on 2MHz upwards. ADSL2 uses 25kHz - 2MHz, and thus should be unaffected by PLT, but VDSL (as used by BT Infinity) uses up to 30MHz, and looks somewhat vulnerable to interference. If anyone's in a position to test this, I should be very interested to hear their results!

      [1] http://www.ban-plt.co.uk/tests.php

      1. MJI Silver badge

        BT do both

        Installed Infinty and sent me new Powerline adaptors.

        Why do I need them when I have a perfectly good piece of Ethernet cable to the BT Vision box.

      2. Anonymous Coward
        Anonymous Coward

        VDSL and PLT

        VDSL and PLT are commonly used together in Belgium (highest deployment of VDSL in Europe) to deliver TV over IP (more than 40% of IPTV subscribers use them).

        Belgacom (the Belgian incumbent telco) are certainly in a position to test this, they supply both the VDSL and the PLT adapters....

        1. matt 83

          yeah

          but they don't have ring mains in Belgum

  15. Timfy67
    Unhappy

    Why is it...

    after sitting exams, paying for licenses, calibrating my equipment to 5 decimal places of a MHz and reporting every contact I make via my legally required log book... if I cause the slightest bit of rf interference ofcom can come in and confiscate my entire multi thousand pound set up.

    And yet when my local "I know everything about networking", PC world loving neighbour wipes out everything within a 50 MHz range with broadband radio interference it's called progress?

    And by the way, there is a hell of a lot more radio traffic below 50MHz than just amateur radio. http://www.fcc.gov/oet/spectrum/table/fcctable.pdf

    1. Anonymous Coward
      Anonymous Coward

      so

      get yourself some plt gear and if they come knocking, blame it on that.

    2. Keris

      You don't need a logbook

      Although I agree with the substance of your comment, you are mistaken if you think that a logbook is "legally required". Ofcom can require you to keep a log, but unless they do so (generally because they are investigating reported interference) there is no legal obligation to do so. Paragraph 12(1) of the terms, conditions and limitations:

      12(1) For the purposes of any interference investigation, to determine compliance with the terms, conditions and limitations of this Licence, or for any other matter concerning the enforcement of any relevant legislation, the Licensee shall at the request of a person authorised by Ofcom, keep a permanent record (a “log”) of such matters concerning the operation of the Radio Equipment, over such period, and in such form, as the authorised person may require.

  16. PaulWizard
    Thumb Down

    Really?

    Drops back to HF so only bothers HAMS?? Two things wrong with that, firstly hams aren't the only users of HF, plenty of other services below 30MHz, secondly you are forgetting harmonics, transmissions that appear on multiples (roughly) of the transmitted frequency, caused by the fact that these POS don't have adequate filtering in the first place.

  17. Anonymous Coward
    Anonymous Coward

    It's the retailers I'm annoyed at...

    When I bought our HomePlugAV kit, it never occurred to me that it might cause problems like this (I may well be a computer geek, but I'm not an electrical engineer).

    It rather annoys me that powerline Ethernet equipment is sold without any kind of warning or information on the potential problems it can cause. Granted, I can understand the commercial reasons why the retailer wouldn't put up a notice like "warning: this equipment can knock out radio signals over a wide area, and may well end up being banned if OFCOM can be shamed into it", but I think those selling the kit and not warning non-technical consumers of the risks, should bear at least some of the blame for the situation.

    Would I buy PLT gear now, knowing what I do? Unlikely, if I could figure out how to thread CAT5e cabling around our house without provoking mutiny - it might've ended up cheaper than the HomePlugs, and it would probably be Gigabit Ethernet-capable. What to do...

    1. This post has been deleted by its author

      1. Oliver 7
        Grenade

        Eco-fascist muppet!

        That article correctly claims that in 24 hours of operation a 2 plug setup will consume 240Wh of electricity. Multiplied as it is in the article across the whole of the UK for a year, it sounds astronomical. That is until you figure out that...

        My kettle is rated 3000W and takes around 3 minutes to boil a litre, that's 150Wh right there! The average household boils their kettle four times a day, a total of 600Wh. My fridge (no freezer unit) consumes 146KW per annum, etc, etc, etc.

        1. This post has been deleted by its author

          1. Oliver 7

            So what?

            These plugs are a quick and easy way to set up a network where wireless is not an option. Unless you have the tools/skills and fancy doing all the manual work yourself, you'd spend a fortune having someone run CAT5 under your floorboards, and what happens if you move the PC? It's not a solution that's going to fit every household anyway but it's a bloody good, simple, cheap solution to some folks' network issues.

            This article talks about DAB radios, they use around 5W! The humungous tellies that people buy these days use more power than traditional models. Games consoles, BDs, PCs, NAS boxes, all kinds of chargers for mobiles, toothbrushes, etc, everyone has tumble dryers and dishwashers these days (I don't as it happens), etc. All the extra gubbins that folk have these days and you're quibbling about a couple of PLTs? Why am I getting downvoted for pointing out how silly that sounds?

            1. Oliver 7

              Downvote this!

              Fuck off you fascists!

  18. Paul 135
    Grenade

    PLT should be made illegal

    Seriously people, get off your lazy arses, get your drill out, and install some cat6. It's a superior solution in every way, any will save you even more hassle in the long-run.

    1. Anonymous Coward
      Flame

      Rent?

      Mind paying my landlord to pay an "approved" electrician to fit cat5 in my rented flat with an ~6ft stone wall?

      1. handle

        Approved

        I agree it's a problem in rented properties, but you wouldn't need an approved electrician to install network cable - there's no mains wiring involved.

        1. Anonymous Coward
          FAIL

          Rent

          Perhaps you should have looked for a property that had already been cabled up. There are plenty of them about, though unsurprisingly they get snapped up quite quickly. Let me know if you'd like an explanation as to why.

        2. Anonymous Coward
          Flame

          Requiring approved

          You don't *need* an approved electrician in the same sense you do for mains jobs, but that doesn't mean my landlord will let me ask anyone I fancy to drill holes in the wall now does it?

          As for getting one pre-cabled I live in a town where most of the accommodation is of the Victorian era and there's an acute lack of housing. If you like I can explain why reasonable rent for a reasonably nice flat in a reasonably nice area, reasonably close to where I work trumped cat5 on my desired features list...

  19. Dazed and Confused

    @Paul135

    drilling wholes all over the house and installing cat6 cabling (it'll be cat7 next year, then cat8... , just like it used to be cat5) and then making good all the walls, re-plastering and re-decorating isn't exactly going to be easy is it now.

    Sadly the builder wouldn't let me come in and lay network cabling all over the house before they did the plastering, otherwise it would have been really easy.

    PLT kit might be a total PITA, but it is certainly easy.

    Besides DAB doesn't work around here too well anyway.

    1. Paul 135

      sack your builder

      Cat5 is still perfectly good to install today for gigabit Ethernet. It's just that for a new install you might as well go cat6 to get 10Gigabit Ethernet future-proofing possibility. Considering 10Gigabit is a long long way away even today (who even has application that needs the full Gigabit bandwidth?), I don't think you will need to worry about the likes of cat7, cat8 etc making your current installation obsolete. Besides, your good ol' cat5 will never become as outdated as the rubbish PLT!

      PS: if your builder wouldn't let you lay your network cable then you should have sacked your builder!!!!

      1. Dazed and Confused

        @sack the damn builder

        I wasn't employing the builder I was buying a house from them, very different situation. When talking to new house builders, some would let you come in and lay network cabling, others wouldn't. At the end of the day you have to buy the house from the people who are selling it. Fully wired networking isn't the only consideration. Besides in hind sight I wouldn't have put it past them to have found a way to wreck any cabling I'd put in.

        On the other hand, when the front garden was re-done, I had conduit run from the study to the garage so all the noisy UPSs and server stuff could be moved from the house. CAT5 is for whimps you really want fibre around the house not just fibre too the house. Now if only I could get BT to pull their damn fingers out.

        1. Anonymous Coward
          Stop

          @Dazed

          Buying the house before it's built really isn't any different, if anything it's a much better situation, the developers will bend over backwards to accommodate you. Had you made installing the cabling a condition of sale I'm sure you would have had no objections - I've had entire walls moved in new builds. They might not have wanted you on the property during the build for health and safety reasons but they would not have objected to having a contractor install whatever you wanted.

          The problem was not what they would or wouldn't let you do, it's that you either asked the wrong question and or you didn't stand your ground.

    2. Baskitcaise
      Coat

      "Besides DAB doesn't work around here too well anyway."

      Prolly all those PLT installs blanking out the signal?

      Mines the one with the ether-killer in the pocket.

    3. J-Wick

      Ummmm...

      I ran network cable along the skirting boards and secured it with cable clips - seems to work ok and is practically invisible. Wife didn't complain. It's only an apartment so only one floor to deal with though...

    4. Anonymous Coward
      Thumb Up

      "the builder wouldn't let me come in"

      lol whipped.

  20. ElNumbre
    Alert

    YMMV?

    DAB and FM works alright for me guvnor. In fact, one combined DAB/FM/Interwebz 'radio' is connected via Ethernet/PLT with issues whatso ever.

    I'm surprised however no-one has found that PLT causes cancer, all those bouncy radio waves flinging themselves out of the power cables into the air. Think to kill it off, the haters just need to get a piece in the DM saying how PLT is an invention by foreigners giving our hard-working families AIDS or something.

    1. Splurg The Barbarian
      Thumb Up

      Works OK for me too

      Moved into a new build home last year, no way the missus would let me drill holes and run cable, so for my HTPC and XBox360 I have a homeplug upstairs to connect to the router downstairs. So far I've had no issues and a DAB radio is used every day in the kitchen without any interference.

      Had missed the stories of interference with these devices, knew about leakage etc but will maybe run a few tests, but as said so far everything works a treat and no issues at all for me or the neighbours(I did ask them though when I fitted it).

      1. Anonymous Coward
        Anonymous Coward

        @Splurg

        You didn't think to have the developers install the cable? Having lived in two new-build (housing development) properties, both times the developments specifically invited minor modifications to the design during the build. If all that was asked for was laying in some cabling they'd be laughing, there's really nothing easier to do in a new build.

        What's more surprising is that in this decade new builds aren't coming with Cat 6 to every room as standard.

  21. Anonymous Coward
    Black Helicopters

    No PLT - CAT5 foreva!

    I got my drill our 5 years ago and ran 2 cat5 to every room in the house [rewiring a 3 bed terrace is useful for more than powerlines]. Love watching den blinkenlights on the 24 port in the basement.

    Seriously though - gigabit [wired] networking vs PLT to blackout your radio/tv is a no-brainer. Cat5 rules

    On the other hand, in mid-summer with neighbour's radios/tv's blaring - PLT has a place to enforce EM blackout.....

  22. Anonymous Coward
    Anonymous Coward

    One man and his hobby...

    ... would be enough for a conscientous ofcom. The rule is simple: No preventing other devices to work. Powerline clearly does this, so the complaint is clearly valid. Nowhere in the law does it say "does not count if it's HAMs" or "does not count if it's just one man" or "does not count if the victim is someone's hobby". Interference is interfecence.

    Of course ofcom would really like to dodge having to go out and gather the evidence themselves, but the arguments so far fail to inspire confidence in ofcom's ability to fulfil their remit. In other words, if they refuse to budge we'll have to connect some boots to assorted backsides.

  23. jason 7
    Alert

    I remember mentioning this in a hi-fi forum

    a few years ago and was laughed at for wondering if it caused an issue for such things as radio and hi-fi.

    Well f**k you, you audiophile tards!

    Thanks, I feel better now.

  24. Anonymous Coward
    WTF?

    Sadly the builder wouldn't let me come in

    Just whose friggen house was it?

    Should have installed trunking/ducts then you could have passed the wires later.

    1. Anonymous Coward
      FAIL

      Installation

      I'm guessing this was a new build? Well why didn't you run the cabling and leave it in situ behind the wall. Mark the spot on the floor boards / measure the distance from the door / whatever then when you move in armed with a wire coat hanger bingo you have your network. Enjoy your PLT, loser.

      1. The Alpha Klutz

        or heck

        nail it above the skirting boards with cable clips. Not as clean as having the cable concealed, but certainly an easy and quick solution. Better to do it when you move in than years later when all your shit is in the way.

  25. Banther dodo
    Thumb Down

    Ofcom = inept

    Clearly they know f--- all about what they are supposed to do.

    PLT should never have been allowed to go on sale in this country.

  26. Anonymous Coward
    Headmaster

    Interference

    I've driven past houses while listening to the football on Radio 5 (AM) where screeching can suddenly be heard as well as the aforementioned ticking. From the description I can only assume it was PLT devices in use.

    If they are interfering with the broadcast bands at that kind of distance they should be banned.

    Mind you, anyone with a Sinclair Spectrum will know that the humble Speccy could knock out AM and FM at a fair old distance. I never did tell the neighbour that his interference to LBC was me playing Atic Atac.

    1. This post has been deleted by its author

      1. Synonymous Howard

        @Early computers

        Ahh, yes, those were the days when you could profile and debug your code by placing an untuned AM radio next to that 8-bit micro and listen for the clicks and bursts in the background noise ... happy simple days when 13 registers were better than 6 ... INC (HL) anyone?

        I'll get back to the pipe and slippers now.

    2. Anonymous Coward
      Anonymous Coward

      Re: Interference

      "I've driven past houses while listening to the football on Radio 5 (AM) where screeching can suddenly be heard as well as the aforementioned ticking. From the description I can only assume it was PLT devices in use."

      Nah, it was probably just the commentators.

  27. Geoff Thompson

    Not simple it seems

    I have PLT to connect my hub downstairs with one PC upstairs which has poor wifi connectivity. I have four DAB / FM radios, one of which is 2M from a PLT unit. No problem with DAB or FM. My neighbours likewise. Not sure what frequency the PLTs are using; they came free from BT internet a couple of years ago. The nearest HAM is about 750M away. I doubt if I am bothering him.

    1. handle

      Of course it's not simple

      I suspect you have nice strong DAB and FM signals, and/or the topography of your wiring is such that it does not radiate well. Either will ensure a good ratio between the wanted and the unwanted signals. If every PLT installation broke every FM and DAB receiver, there would be no excuse to do nothing about it.

      1. Anonymous Coward
        Thumb Down

        Er, no....

        ....actually the reason that many people here are not reporting problems with FM and DAB is because they are using PLT devices that do not use the VHF spectrum, only HF.

        The newer generation have the Gigle chipset (amongst others) and this transmits at 50-300+MHz and will wipe out DAB and FM in many cases.

  28. Robert Carnegie Silver badge

    If it's your own home then it's your choice (if not legally)

    And DAB isn't so useful at home, because you can get most of the radio channels on your TV if you have one - or over the new RadioPlayer web site and your Internet PLT connection of course.

  29. Anonymous Coward
    Anonymous Coward

    We're not all network engineers, electricians, builders, etc...

    All right: I know that some of these "just get off your lazy backsides and install CAT5e cabling in your house" posts are presented with a knowing wink, but still...

    Believe me, I would *love* to have CAT5e running between the rooms where I need wired network connections (not least because I'd finally get Gigabit Ethernet that way), but there are a few teensy obstacles to overcome (multiple rooms on different floors, doorways to route cable around, Wife Acceptance Factor, me barely being able to install a lightbulb on the DIY front, etc. etc.).

    At least try to understand why HomePlugs and their ilk are popular with non-technical and/or non-"handy" users - if you can avoid wireless and significant work on your house by plugging an adapter into a wall-socket, and you weren't aware of the RF problem (as I wasn't), wouldn't you?

    Of course, I don't have that excuse now. I almost hope OFCOM *does* ban HomePlugs, as I can then offload much of the likely wifely opprobrium ("you telling me you wasted 100 quid on those things??!") onto them...

  30. Dave Robinson
    Alert

    Works for me

    My understanding is that HomePlug AV (200Mbps) uses 2MHz to 30MHz, and doesn't transmit when idle. I've got HomePlug AV in my house, and various DAB radios, and never had a problem. Also, I believe that HomePlug AV is notched on the main shortwave bands, and in any case only interferes within a range of about 30 metres anyway. I can't see any big masts or beardy sandal types within a 100 metres of my house, so I'm probably OK.

    The faster (500Mbps and 1Gbps) units that were tested use a wider frequency spread, and hence are more likely to interfere with DAB (and anything else).

    Given that I live 500 metres from a TV and mobile phone transmitter, I'm not too worried about the additional RF that my system generates, although when we finally get BT Infinity around here (or maybe even NTLVirginWestTele Cable) then I'll probably pay an electrician to ruin my walls for me.

    1. Slim Chance
      Flame

      Doesn't work for me

      PLT would have been a great solution for me being a of bit a lazy git on the diy front.

      Unfortunately the adapters I bought and returned wiped out my FM & DAB radio reception.

      So I had to resort to a large masonry bit in my black and decker plus a bit of cable to get the desired connectivity.

      The only good use the adapters had was to block out the Archers & Desert Island Discs.

    2. Anonymous Coward
      Boffin

      A few calculations....

      ....suggest that if the PLT device is 30dB (1000 times power) above the radiated energy limits that it will be audible at about 30 times (square root of 1000) the distance that a compliant product would.

      The EMC regulations were intended to keep interference down to less than 10m range, essentially within one property in a domestic situation. Multiply that by 30 and you get the 300m interference ranges that people are reporting.

      Oh and just to add one other thing, while PLT may notch in the amateur bands that isn't much use if you want to listen to short wave broadcasters which some people still do.

      Let this nonsense continue and sooner or later we'll all be wondering why our expensive radio-connected gadgets stop working entirely. It could happen, EMC standards are what allow and guarantee interoperability.

    3. Pypes
      WTF?

      notched?

      "My understanding is that HomePlug AV (200Mbps) uses 2MHz to 30MHz, and doesn't transmit when idle. I've got HomePlug AV in my house, and various DAB radios, and never had a problem. Also, I believe that HomePlug AV is notched on the main shortwave bands"

      Seeing as how 2 Mhz to 30 Mhz not only covers the entire short wave band, but also comes pretty close to defining it, I don't really see how they can possibly be notching out shortwave frequencies.

    4. Anonymous Coward
      Boffin

      HF notching....

      ...is applied to most of the PLT devices, but it isn't a cure all. For a start it only notches the amateur bands, if you want to listen to HF broadcast radio, or the WWV 10MHz time signal from Boulder then you are subjected to the full unattenuated blast of the device. The other thing is that the notches don't work too well if there are lots of mains power supplies connected. These days the switch mode power supplies have semiconductors right up near the mains input and these are non-linear which means that intermodulation between the PLT carriers (they use OFDM, so have closely spaced sub-carriers) will cause spectral regrowth which will reduce the notch depths.

      As for the big masts and all that, well a lot of amateurs these days try not to advertise their presence too much because people tend to blame them for interference that they are not responsible for.

      Oh yes, I may have a beard, but I certainly don't subscribe to the wearing of sandals ;-)

  31. Anonymous Coward
    FAIL

    PLT is a VERY bad idea !

    What is really dissapointing is that today all kinds of electronic "crap" enters

    the market, I doubt that some of it is tested properly regarding EMC.

    I have encoutered mobile phone chargers, laptop computer chargers, plasma-TV's

    etc. that disturbs amateur radio and broadcast frequencies. But also the same type of

    equipment that does not. Why cant manufacturers produce well proven products

    that does not create radio interference ?

    It should be very easy...... but no. In stead they make a mess out of it....

    PLT/PLC creates a lot of electromagnetic "pollution" of the radio spectrum, and

    all this because people can't run a CAT-5 cable in their home ....? The whole

    PLT/PLC system is a very bad idea. Skywave propogation and PLT/PLC will also

    increase the total background noise over large distances on certain frequency

    areas. This will be an increasing problem in the future, as solar activity

    increases and creates better reflections of higher HF frequencies.

    PLT/PLC does interfere with already well established radio services and therefore should be illegal. Internet access using CAT-5 or Wifi is OK, we really dont need this PLT/PLC things, it just creates problems.

    I hope PLT/PLC is removed from the market very soon.

    Roar

    1. handle

      It isn't very easy

      ... to design equipment the size and technology of, say, a 50" plasma TV (lovely high voltage spikes all over the panel) that doesn't radiate significantly, without spending a prohibitive amount on screening and filtering. Consumer electronics is a very competitive business, and manufacturers will take as many liberties as they can in order to shave off a few pennies so that you, the consumer, buy their product over someone else's. Considering that the legal requirements are so woolly, self-certification is the order of the day, the symptoms are very hit and miss and the regulators, as we've seen, are useless, is it any surprise that we are in the mess we're in?

      1. Anonymous Coward
        Anonymous Coward

        "It isn't very easy"

        SO WHAT if it isn't very easy? Rules is rules, EMC compliance is one of them, if folk can't stand the heat, they should either not join in, or they should expect trouble if they get found out.

        Anyway, it is possible to design general consumer electronics that stays within the spirit and the letter of the law.

        It is not possible to design PLT kit that stays anywhere near the law. It simply can't be done. The stuff cannot be compliant and should never have been allowed to go on sale.

    2. Richard 12 Silver badge

      "Why cant manufacturers produce well proven products..."

      They can, but some simply don't bother.

      "CE" is on the trust system - a manufacturer or importer that puts the label on their product is stating "We certify it meets the appropriate blah blah blah."

      No third party is required to check that it actually does.

      So some of them don't bother testing at all and are just hoping that it's ok - or even know that it isn't and are simply hoping that they don't get caught.

      And the fact is, they'll almost always get away with it - the tests needed to show that a product does/doesn't comply with EMC regs are quite expensive, so equipment rarely gets retested by a third party and nobody ever realises that they are breaching the regulations.

      I recall a few years back seeing the results of tests of a fluorescent ballast that was used in a lot of hospitals that was absolutely terrible on conducted emissions - possibly even interfering with critical mains-powered equipment. The importer hadn't bothered doing any tests at all, and weren't caught until a rival thought the design looked wrong and had them tested to prove a point. (And of course, hopefully get a sale).

  32. Will Godfrey Silver badge
    Stop

    BBC must be lying

    OfCom says there is no problem.

  33. mark phoenix

    Intenet radio has replaced Dab in the home

    PLT is far more useful than Dab. The version of Dab the BBC is using is crap but who cares anyway as Dab has been replaced by Internet radio in the house.

    1. Anonymous Coward
      Anonymous Coward

      Think it through...

      Plenty of people don't have internet access. A recent survey had 30% of people saying they didn't have broadband (or indeed a computer) and have no intention of ever getting it. Are you saying that these people should suffer interference from the neighbours PLT devices? Lets see, thirty quid for a DAB/FM radio or many times that for a PC plus ongoing broadband charges.

      And what about car radios? As several commentards have pointed out they are getting interference when driving through residential areas, no proof that it's PLT, but it's likely. Are you saying they should get broadband in their cars, just so PLTs can continue in use.

      Face it, some PLT devices (not all) break the law on RF interference. Ofcom are too toothless to do anything about it, but that does not change the fact that there are devices on sale that are technically illegal.

  34. bob_bob

    What frequency does WiFi equipment operate at?

    What frequencies do home WiFi equipment operate at? I have never had any problem of DAB/FM knock-out and we are running PLN equipment (85Mbps) and WiFi (does not reach the whole house before you ask). Assuming that there are no issues with WiFi knocking out signal then is there a reason we couldn't use the mains wiring as a waveguide for the same frquencies that the WiFi uses and thus confine leakage to a "harmless" frequency range?

    We do own our home (well the bit that the bank doesn't own anyway) but retrofitting CAT5/6 cable throughought the house to have outlets wherever there is currently a mains socket is more than a modest "get yout drill out" exercise so it is no surprise that PowerLine is a popular option. It has a big dollop of "it just works" going for it.

    For me, PLN > DAB because I already own FM radios a plenty and I feel no need to part with my hard earned to replace them all with an "either it works or it doesn't" so called solution. I like the idea of internet radio -- for which I will need an internet connection at the point of use -- hello PLN again (if the WiFI won't reach).

    (Paris doesn't understand electronic engineering either)

    1. Synonymous Howard

      I got my drill out ..

      a few years ago and it was relatively painless to put cat5e and dual sockets in each main room, hiding the cable runs on the top of the skirting boards (finally a real use for them!) .. getting it to the loft without going outside was a bit, ahem, interesting but its been sweet to be able to throw video around at high-speed between the various servers and devices with no spluttering or buffer-lag.

      I just wish I lived opposite an exchange like my dad (rather than miles away) .. all that bandwidth and he has no real use for it .. life's not fair sometimes .. I'm still waiting for the promised 21CN ADSL2+ upgrade (should have been last month according to BT in January). 10 years ago a cable company put a green micro-cabinet at the end of the next road but never quite got to the bit where they stick some kit on the other end and offered any service; thank you Diamond Cable for, umm, nothing!

    2. This post has been deleted by its author

  35. Anonymous Coward
    WTF?

    Not giving up my homeplugs...

    ...and beside, since OFCOM won't come down on ISPs fraudulently advertising speeds that can't be achieved and using the word 'unlimited' when things aren't, I don't think any ruling on Homeplugs need apply to me, until they've got their house in order.

    1. Anonymous Coward
      Thumb Up

      I'm going to massage your skull with a lead pipe

      so it's a good thing that the law doesn't apply to me either.

  36. Andy Enderby 1
    FAIL

    does nobody submit kit for RFI testing any more.....

    Back in the nineties I worked for a PC manufacturing company with a big faraday cage, used for RFI testing of just about everything. Want to sell kit to choosy customers with something a bit out of the ordinary in the box (gigabit ethernet for example)? Guess what, they have you test the bleeder in the configuration you want to sell....Which is in addition to routine certification testing of just about anything new coming out of R&D. Here we have a technology that obviously runs high frequencies over unshielded lines, that is fairly obviously going to bleed broadband RF in all directions, as pointed out by others in this thread, and obviously should have been subject to thorough testing.

    Mind you, with O/S and app vendors essentially unleashing barely tested wares onto the market, why should hardware vendors be any different......

  37. Neil 7
    FAIL

    No FM problems here

    I just spent the afternoon testing several Netgear 500-AV Powerline units (2x XAV5004, 1x XAV5001).

    Using iperf I observed very acceptable throughput rates between two units located in different rooms on the same floor - actual TCP and UDP transfers averaging about 130Mbits/sec - and there were NO FM problems whatsoever (not according to the Sony clock/radio alarm that was tuned to BBC Radio 2).

    I've no idea if these Netgear devices cause any DAB problems as quite frankly I have no DAB receivers to test with and no intention of ever buying one.

    Maybe Powerline does cause problems for FM and DAB, but Powerline devices also have firmware that "notches out" certain frequencies to avoid causing any interference so perhaps these BBC engineers were testing with firmware that didn't do such a good job of notching out, or perhaps even using the wrong firmware completely.

    For reference I tested devices with the latest 0.2.0.9CE (Central Europe) firmware, there's also different firmware available for North America (0.2.0.9NA) that no doubt notches out different frequencies according to local regulations.

  38. Argus Tuft
    Black Helicopters

    how long...

    before Google cars start hoovering up the leaky data?

    1. Dx-Digger
      Pirate

      Insecure!

      http://www.theregister.co.uk/Design/graphics/icons/comment/pirate_32.png

      Its already been shown how easy it is to hack into networks using these devices!

      Identy theft NO not me officer, I didnt steal it he just transmitted it and I acidently picked it up!

      You should have seen all the porn he was downloading, and what they get upto on their webcam!

      Lordy Lordy!

      http://www.theregister.co.uk/Design/graphics/icons/comment/gates_horns_32.png

  39. Anonymous Coward
    Boffin

    Yes, but me telly goes wonky.

    Why is it every time a 2 stroke scooter goes past me house the freeview goes AWOL regardless of the receiver used?

    I would complain but it mostly has the effect of improving the program I'm watching.

    1. Big_Boomer Silver badge
      Boffin

      Wonky Telly

      Older scooters (and some other motorcycles) use a magneto to produce the spark.

      If this is not housed in a Faraday cage and the leads and plugs used are not supressed then you essentially have what is known as a spark gap transmitter.

      Every time they produce a spark they emit a burst of noise across a wide radio frequency range (mostly LF & HF but sometimes VHF) and can interfere with lots of things.

      If you are getting interference on yer telly, then it's an old POS with crap filters.

      All modern tellys have decent filters.

      As for it improving the programme you are watching, that's not hard these days. <sigh>

  40. Jim 15

    Silly(?) suggestion?

    If the problem is PLT knocking out DAB and FM radio in the home, use a Sky box or a PC or Internet radio device to listen to radio stations from all around the world, not just UK based stations, and to do that ... plug the PC or Internet radio into a PLT. ;-)

  41. Dx-Digger
    Unhappy

    THEY FAIL EMC compliance fullstop!

    When All is said and done these devices DO NOT meet the legal requirement for EMC compliance! wether HF or VHF! And OFCOM who are supposed to police such breaches turned a blind eye! They had an independant EMC report for the devices which they refused to publish showing just how bad the devices were, it took a Freedom of Imformation ACT to get the information released. And even now they still do not appear to be interested in the problem.

    And ofcourse we are all wondering HOW MUCH DID BT PAY THEM TO TURN A BLIND EYE!

    Because that is how it looks!

    Absolutely DISGUSTING!

    http://www.theregister.co.uk/Design/graphics/icons/comment/unhappy_32.png

    But then isnt OFCOM a government body! enough said!

  42. Hubert Thrunge Jr.
    FAIL

    Never mind DAB or ham radio. Try ATC

    Wireless waves have no regard for boundaries. Signals moving in the general direction of UP often have no scenery to attenuate them.

    When a Boeing makes an unexpected landing because it's ILS system was fubar'd by a bit of non-compliant PLT, Ofcom will select top gear and pedal backwards furiously.

    They refused to licence GPS re-radiating devices for in-car in the UK use that have a real measurable range of no more than about ten feet because "they *might* interfere with aircraft", yet they allow devices that emit a fair amount of noise in the 108-136MHz spectrum used by air traffic control. Add the amplification of the noise by switched mode power supplies and you could potentially have a few-hundred watt signal generator in certain circumstances, using the house wiring as the aerial system (ants have antennas, radio transmitters use aerials - or radiators to be more precise!)

    When one is installed near a coastguard station and causes interference with 156MHz marine distress frequencies, I'm sure there will also be some frank discussions.

    It is my feeling that Ofcom were leaned on by BIS in the UK, who were probably cavassed (paid off) by BT who were happily giving the devices away with their Home Hub systems as a cheap alternative to decent wifi/network equipment. Wouldn't it have been better to give each user a 305ft roll of CAT5, some boxes an IDC tool, and some plugs?

    I'm a radio professional - I do radio for a living, and emergency comms is my mainstay. This whole saga stinks of brown envelopes.

    An EPIC FAIL on their part to uphold the regulations they are supposed to administer.

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