back to article Radio Society to Ofcom: Hear See you in court

The Radio Society of Great Britian will see Ofcom in court over the regulator's failure to properly investigate powerline networking kit that the society reckons is being supplied illegally. The Radio Society has kicked up a fuss about powerline kit before: it generates interference that mucks about with amateurs' usage, but ( …


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  2. Dave Murray
    Thumb Up

    Go! RSGB Go!

    Almost makes me wish I was still a member.

  3. Anonymous Coward

    Illegal vendors should be PUNished, badly!

    Watch out Rubber Duck, there's a smokey on your tail...

    Rather a HAM fisted approach by the RSGB...

    Any more bad (better) puns?

  4. Anonymous Coward


    Interesting, and not just for the RSGB.

    One of the UK's best known suppliers of powerline kit is BT.

    One of the UK's best known suppliers of DSL broadband is BT.

    There are people in the BT DSL part of BT that would love to see the BT (and other) powerline kit taken off the market, for the same reasons the RSGB want it off the market - powerline splatters interference all over the RF spectrum indiscriminately, and DSL (especially high speed DSL) relies on having a clean and relatively interference-free environment around the DSL kit and cabling.

    Interesting times ahead, maybe.

  5. Jimmy Floyd

    Working both ways?

    "Ofcom has failed to investigate the claims, this inertia leading to the legal action."

    Tell me, would this implication of a charge of neglect also apply to the police? I'm thinking of Phorm and 'dat sorta 'ting.

  6. Anonymous Coward
    Thumb Down


    By the millions of people using powerline kit against Radio Society... When can someone raise a lawsuit against baby monitor manufacturers for interfering with my bl00dy 802.11g network and forcing me to use powerline kit instead?

  7. Chronos Silver badge

    @ Dave Murray

    Almost, but not quite. They still haven't told us how much they paid for HRT, nor have they justified charging for a training scheme run by volunteers. One wonders whether they'd be pushing so hard if they hadn't cornered the market for advertising in amateur radio in this country.

    Besides, all that's left is multi-band CB. They pushed for this devaluation of the service and now they've discovered that others see it as being worthless, yet they didn't listen to this argument when the members were warning of it eight years ago. Who is suprised that Ofcom now want their payback for virtually removing all regulation of entry into amateur radio at the RSCB's behest?

    .- -- .- - . ..- .-. .-. .- -.. .. --- .-. .. .--. ...-.- It's dead, Jim.

  8. Paul 123

    RSGB and OFCOM

    The RSGB (of which I am a member) would probably be better off making a legal test case against any one of the numerous high street retailers who are selling these uncertified (and therefore illegal) devices. Retailers threatened with fines will react far more quickly than OFCOM.

    These devices are here to stay - it's called progress! I myself use several at home as wireless don't go through 3ft walls too well, so let's get them working properly and checked/certified.

  9. Alex King


    People still use HAM radio? This kind of feels like a battle re-enactment society berating the MoD for driving longbows out of the infantry...

    Seriously though, what's the bigger constituency here, HAM radio enthusiasts or powerline kit users?

  10. Alex Walsh

    Whats certified and what isn't?

    I assume they're referring to stuff meeting the homeplug standard? The stuff devolo, MSI and Netgear et al sell?

  11. Andrew 63


    Powerline aka Homeplug stuff?

  12. Anonymous Coward

    Should try trading standards?

    Given OFCOMs inertia maybe they should try Trading standards as this kit isn't complying to local requirements?

  13. Anonymous Coward

    oan the powerline...!

    Living in a listed building and being prohibited from running cat5 everywhere, I had to find a way around the woeful (< 0.5mbit) wifi signal that I was able to get in my office, the best solution I could find was to go down the powerline route.

    I was worried about installing a kit after reading reviews and comments complaining about interference - even the manual made mention of the fact that it may interfere with TV and other signals. I gave this due consideration (ok, I completely ignored it), then installed the kit anyway.

    I don't know what I expected to happen once I plugged it in... lots of people banging down my door because of the interference I was causing..? Nope, nothing, other than the full 20mbit connection I am payng for transferred to my office without any additional cables, in silence and no interference to any other services I use.

  14. gerryg

    Go RSGB - It's not only ham radio

    The law and Ofcom are supposed to keep the spectrum clean.

    That ships in the middle of the Atlantic are unaffected is not surprising unless they are using an old Sinclair C5 washing machine motor and a long extension lead as we are discussing the effects arising from using BT Powerline kit used on domestic wiring.

    There are people that do DX listening that are affected by this device, it wipes out shortwave listening.

    It seems that unless you are a large organisation affected by any of this then Ofcom won't do anything. Large organisations can usually fend for themselves.

    Perhaps Ofcom could get out of their expensive offices for reasons other than multiple attendances at telecommuncations or broadcasting beanfeasts or offer themselves up for abolition to help close the public sector funding gap.

  15. David Kelly 2


    Greenies complain about all other forms of pollution, why not spectrum pollution?

    There is a reason why legal unlicensed devices will not penetrate 3' walls. Its the same reason you are not allowed to run 500W headlights. While you could see, you would prevent anyone else from being able to see. Keep the power down to reasonable levels and everyone can see.

  16. Fred Goldstein

    Less a problem in the states

    The biggest US ham organization, the ARRL, has been fighting noisy BPL systems for years, but has no problem with the in-home (HomePNA) kit on market here. The vendors, who do pass FCC approval, are careful to notch out the ham bands. It sounds like the UK market hasn't approved anything, or isn't enforcing the law, so unapproved garbage is coming to market instead. We've seen this sort of problem before. Early PCs were very noisy too, but rules were imposed and enforced (that counts), and vendors learned to make them quieter.

  17. Steve Todd

    @AC 12:55

    "When can someone raise a lawsuit against baby monitor manufacturers for interfering with my bl00dy 802.11g network and forcing me to use powerline kit instead?"

    As 802.11g runs on the unregulated 2.4Ghz band then, providing the baby monitor doesn't exceed power limits you're stuck with it. Urban 802.11b/g networks are forever interfering with each other anyway as there are effectively only 4 channels they can run on. Switch to 802.11a/n on the 5Ghz band where there are (1) more channels, (2) rules about locating free channel space and (3) rules on dynamic power (i.e. not max power all the time, only use as much as is needed).

  18. Andy 97

    CQCQ - fail

    It's pretty sad that nobody actually checked the RF harmonics in this kind of kit before it was offered to the public....... oh..........

  19. Anonymous Coward

    My response...

    ... to some radio ham knocking on my door and demanding I use alternate networking would be "Why don't you use another form of communication? Or alternatively you can convince my landlord not to deduct from my deposit for my hacking up the place to lay ethernet, or maybe convince my neigbours to turn off their Wi-Fi so that my signal can get through all the congestion... and are you paying the costs for me to change my setup which I bought in good faith with no knowledge I was ruining your life?"

    To which I'm sure the ham would reply "How dare you, I was here first, this is my right!".

    Both good cases...

    At the end of the day nobody should have special rights to ask people to shutdown their equipment or on the other side of the coin to ruin signals with their equipment etc. Ofcom as a regulator should be ensuring that manufacturers are producing kit which is properly certified and doesn't produce excess interference - the average consumer can't be blamed for things beyond his/her understanding (i.e. creation of intereference) that's what we have a regulator for!

    Ofcom = FAIL, again.

  20. Anonymous Coward


    Throwback? There is a tendency to think that of course, but look at some of the tech we use today:

    Satellite communications

    Digital modes- PSK31 etc.

    GPS based position reporting systems- APRS

    Email via radio- Winlink

    Earth-Moon-Earth radio bounce

    SDRs- Software defined radios

    But the most visible portion of amateur radio is providing support to the local community. I belong to the city's emergency communications team. You would be surprised at the communications support we provide. For example: 9-11 was one such emergency. Our local amateurs provided health and welfare communications to the city to cope with all the stranded passengers when flights were grounded.

    Bottom line: When your cellphone dies in an emergency due to overload or lack of power, amateurs will keep on working.

    Oh yes. Morse code is no longer a requirement in most countries.

  21. MJI Silver badge

    Horrible things

    I have a couple - unused, thought they were a horrible idea, dirtying the power supply by my TV and HiFi.

    So I fitted an ethernet cable between hub and BT Vision.

    Then I saw the power consumption, a years worth paid for the ethernet cable.

    Good luck getting rid of them.

  22. Anonymous Coward
    Anonymous Coward

    RSGB and OFCOM

    As a licensed radio ham, we get shut-down if we cause interference, to other radio and tv equipment, so get these uncertified things off the air.

  23. Andy Livingstone

    @Anonymous Coward , 13:58

    The topic concerned wires in the UK. rather than in the USA. There are quite a few differences in wiring, Amateur regs and workings, and even "cellphones" between countries, which don't really allow simple comparisons..

  24. Steve X


    Community size isn't the point. If one group is permitted to sell equipment that doesn't comply with standards, even if it only interferes with a few people, then soon others will start importing/selling non-compliant equipment that causes more widespread interference, on the assumption that "he never got into trouble, so nor will I". Standards are there to prevent a free-for-all so that a scarce resource can be shared.

    As to the scenario in "My response", how would you react if, say, your normally pleasant neighbour popped over to ask you not to use your chainsaw at 3pm on a Sunday because her new baby is rying to nap? Would you suggest that she puts the baby somewhere else, or perhaps offer instead to use the saw in the morning, and by the way would the neighbour turn her stereo down after 11pm? There's almost always a way to compromise, and plenty of amateurs end up fitting filters on neighbours RF-challenged TVs, even if the amateur equipment is operating perfectly legally, so that both sides can enjoy their interests.

  25. Anonymous Coward
    Paris Hilton

    CQ CQ


  26. Anonymous Coward

    Re: RSGB and OFCOM

    @Anonymous Coward

    > As a licensed radio ham, we get shut-down if we cause interference, to other radio and tv equipment, so get these uncertified things off the air.

    OK... but if ham/whatever is so great why are you using the Internet to type that post instead of talking to one of your oddball ham freinds?

    Seriously who cares about this ham nonsense, since TAT-1 in 1956 it has been obsolete.

    Ofcom should punish these luddites for thier law suit by selling off thier spectrum to someone who might actually use it or better still, revoke their license and bag the frequencies for some future technology.

  27. Anonymous Coward

    @alexs and others

    "Seriously though, what's the bigger constituency here, HAM radio enthusiasts or powerline kit users?"

    Seriously though; what relevance has the number of users got ?

    Communications/networking kit is covered by a huge number of standards and regulations. This is a good thing. It ensures stuff works as it's meant to - doesn't leak and interfere with other kit.

    This is kind of fundamental to the way all this stuff works.

  28. Anonymous Coward
    Anonymous Coward

    Ofcom: save any more problems for everyone. Get rid of PLT now.

    Presumably, those who say they ought to be allowed to use devices that obliterate radio reception because 'there's more people using PLTs than short wave radio users" would bow out gracefully if, say, a new mobile phone was introduced that jammed their landline. After all, there's more people using mobile phones.

    Devices are either legal or they aren't. These PLT devices completely contravene EMC law by deliberately and by design radiating huge signals on hundreds of frequencies at the same time. They're clearly illegal, and they'll soon be removed from the market. Convenience isn't a reason to allow them. It'd be convenient for me not to buy a TV licence or pay my taxes, for example, too.

  29. Anonymous Coward
    Anonymous Coward

    @ MJI

    "I have a couple - unused, thought they were a horrible idea, dirtying the power supply by my TV and HiFi."

    You'd think by now manufacturers that are charging £lots for supposedly SOTA consumer electronics would have got the hang of designing a power supply which does a decent job of rejecting mains borne interference - after all if your even if you don't have PL networking kit your fridge-freezer, washing machine, or microwave probably will all be wreaking their own brand of electrical mayhem...

    "So I fitted an ethernet cable between hub and BT Vision."

    If your router, your TV, and all your other kit are in the same room it would be pretty silly to do anything else. In my case the router (and the file/print server, and 2 PCs) is connected to an old-skool engineer installed combined ADSL filter and 'phone master socket in the office which is upstairs and in the opposite corner of the house to the TV (and the X-Box, and the Wii, and the media player). Running CAT5 between the two in a domestically acceptable manner would be a nightmare of lifting floorboards, drilling holes, chasing out plaster to put cable ducts in, and making good decorating to hide it all and that's before I even think about the boys rooms...

    Before the first couple of powerline boxes came with the BT Vision box all the stuff outside the office used to run (or more accurately sort of shamble and lurch along like an extra in a zombie movie) on 802.11.whatever[1] with a wireless bridge attached to a hub in each room we needed connectivity - this sort of worked until A) the number of neighbors with (badly configured, all left on the default channels) wireless networking reached a critical point and B) the boys started wanting to stream video off the server to the PCs in their rooms at which it all became a huge steaming bucket of fail. By contrast the powerline stuff Just Works (without any obvious adverse impact on the ADSL or anything else in the house, including my guitars, ancient valve amps, and recording kit) without having required so much as a reboot since it was installed...

    The idea that everyone using this kit is simply too lazy to pop into the local POV world to buy an extra ethernet cable doesn't really stand up.

    [1] We went through three generations of kit from 4 suppliers over the years.

  30. Peter Gathercole Silver badge

    Powerline Networking

    As I understand it, because the devices are not intended to broadcast wireless frequencies, they avoid a number of the standards that apply to wireless transmitters.

    The standards they fall foul of are the electrical and electromagnetic interference standards, and it does look like some devices are seriously dirty in this respect. And it looks like the frequencies that RSGB are trying to protect are not actually frequencies used by the devices, but unintended harmonics of the carrier frequencies. This should be fixable in the design without making the devices unusable.

    I believe that OFCOM (if they are the people who police electromagnetic interference) should crack down on the manufacturer of devices that do not meet the required standards. I wish someone would produce a list of the devices that are dirty, though. I am using some Netgear homeplug devices (which work very well), but I don't know whether they are causing a problem.

  31. Chronos Silver badge

    @AC 15:43

    They can't. Most of the amateur bands are allocated by the ITU, whose stick is a little bigger than Duffcom's, on a region by region basis. Duffcom can, at most, revoke amateur access to them but they cannot, under any circumstances without going to the ITU cap in hand, reassign them to anything else. 70cms may just be an exception, with the MOD being the primary user and amateur radio getting access on a secondary basis, but I've been expecting 70cms to get taken away for years now and it's still there in the schedule.

    Ho hum, whatever. If there were anything left worth saving I might GAF.

    73, as they say in certain parts of Italy. Or is that "HOOOOOOOOOLA" as the ALC kicks in?

  32. Richard 35

    The word on PLT

    There are a couple of things that you "I'm OK, pull up the ladder mate" PLT advocates do not seem to be able to understand or grasp. Let me explain them.

    I) Amateur Radio is not Luddite or out-dated.

    When the Twin Towers came down, cellular and emergency comms went off-air because infrastructure was on top of the towers. Radio Amateurs went in to establish emergency communications networks.

    When the Boxing Day Tsunami occurred, it was Radio Amateurs that were involved in relief efforts.

    Amateur Radio is also part of a number of US disaster relief plans.

    If your mobile phone network goes titsup, your phone is useless. Our kit still works.

    II) PLT is a better use of spectrum than Amateur Radio (et all)

    PLT is not an enabling technology. It is a convenience and competing technology to WiFi, Bluetooth and wired networking. It uses spectrum between about 2.4MHz and 28MHz which just happens to already be allocated to Broadcast, Aeronautical, Military, Amateur and other users.

    The fundamental issue is that PLT's do not comply with the essential requirements of the Electromagnetic Compatibility Regulations. These state:

    (2) Equipment shall be designed and manufactured, having regard to the state of the art, so as to ensure that:

    (a) the electromagnetic disturbance it generates does not exceed a level above which radio and telecommunications equipment or other equipment cannot operate as intended...

    This isn't just a little bit of text from a standard; this is UK law. ALL products have to comply with this. Go look it up for yourselves.

    It also states that to affix a CE mark on a product, it has to conform to the essential requirements. PLT products do not conform to this, and this is the reason for legal action.

    PLT products also do not comply with EMC regulations that they claim conformance to (eg EN55022 in the case of the Comtrend DH10-PF). This has been proven by the UKQRM group under certified laboratory test conditions. The upshot of this is that the EMC regulations (ie the law that prevents one thing interfering with another) go out of the window. Allowing PLT opens the door to any crap hitting the market and flouting the law. Today it's affecting the Short Wave spectrum; what if it was FM or DAB next? I for one would piss myself laughing.

    As has also been mentioned, there are real concerns regarding PLT interfering with VDSL, but some simple tests have indicated a possible effect on standard ADSL (intermodulation effects maybe?). ADSL BT vision users may want to do tests with something like with and without their PLT modems running just as a check. It doesn't matter if the supplied Comtrend UPA PLT's are transferring data; they are transmitting garbage 24/7 regardless.

    There have also been instances of BT supplied Comtrend PLT's interfering with customers 27MHz wireless keyboards and mice.

    Do BT care? Those nice people who illegally trialled Phorm without letting anyone know?

  33. frymaster


    "OK... but if ham/whatever is so great why are you using the Internet to type that post instead of talking to one of your oddball ham freinds?"

    so if you use the internet you can't use ham radio? Are you allowed to use mobile phones if you send letters?

    I wasn't aware there was some kind of communication media rationing

  34. Radio1234

    EMC Standards

    The EMC standards implemented and agreed throughout the EC are designed, audited and implemented so all your multiple electronics devices in your home and life exist together in a harmonious way, not interfering with each other. The standards have been agreed throughout Europe and all electronic products are assessed and have to adhere to them. Image if you installed a computer and it interfered with your neighbours radio or TV because the power supply sold with it had no filtering and did not adhere to the current EMC standards. They would be pretty annoyed and well within their right to ask you through OFCOM to remove or replace the offending item. Through the trading standards authorities this device could be removed from the market too.

    The BT Comtrend PLA (and others) is a similar device. It is regulated by clear standards for PLA product. However the fact is that it does not adhere anywhere near to the relevant EMC standards applicable and by rights should never have been allowed to be sold in this country. Comtrend are at fault importing a non-adhering device into the UK, BT are at fault by selling and installing non-adhering product and OFCOM are guilty of refusing to properly investigate the Comtrend devices that are being supplied illegally.

    Well done the RSGB, you have my support in fighting for the EMC law that has been agreed throughout the EC and broken, and in taking on the ineffective government body that wishes to ignore these facts, no doubt influenced by the likes of larger businesses.

    Without strict adherence to agreed EMC standards, there is absolutely no point in having them. If that happens you can kiss goodbye to your daily does of soaps when you neighbour starts up his microwave, computer, X box or any other electronic gizmo for that matter.

    Ignore the EMC standards at your peril.

  35. John Murgatroyd

    More anarchy..................

    The problem is not O£COM or the RSGB.

    The problem is the manufacturers of some of the adaptors.

    Some of the units just do not notch-out the parts of the spectrum used by amateur radio. Those units render listening to practically any radio signal between 1 to 30 megahertz a near impossibility. Those affected, apart from amateur radio operators, are short wave listeners and cb entusiasts.

    As for O£COM removing the use of those frequencies....they cannot. The frequencies are internationally allocated.

    And it may well be that O£COM is not going to be around for more than a few years anyway, since the EU is moving to administer the spectrum over the entire community. The only member countries resisting the move are the UK, Germany and France.

  36. Will Godfrey Silver badge

    I wonder who knows...

    Who managed the first slowscan long distance TV transmission, that was the forerunner of our modern video conferencing.

    Who managed the first reliable UHF communications.

    Who first learned how to use 'satelites' to bounce signals long distances.

    Who is really at the leading edge, and who really are the Luddites.

  37. Andy3

    Enforce the law!

    ALEX KING - This is not a matter of 'who is the biggest', it is 'who is legal?', and the PLT devices are NOT, Amateur Radio IS. The devices do not comply with interference legislation (by a huge amount!), and so they should be removed from the market.

    Secondly, you show your ignorance by suggesting that Ham Radio is 'a throwback'. Modern amateur radio uses all kinds of technology including digital data comms and weak-signal detection schemes you wouldn'r begin to understand, so let's have less of the insults. This is about upholding the law, not 'who's the biggest'.

  38. Paul Widger

    BT Vision are a disgrace.

    BT top brass have been aware of the problems with the Comtrend Powerline Adaptors which the RSGB are complaining about for well over a year, but rather than doing a product recall

    are hiding behind Ofcoms failure to act as a regulator.

    Indeed some would say BT have influenced Ofcom.

    Non radio users may find it interesting that these Adaptors can interfere with wireless keyboards and mice.

    They dont like mains spikes which can make them stop working.

    Recently some users have found they reduce internet download speeds.

  39. AndyMW
    Thumb Up

    Well done RSGB!

    I'm pleased the RSGB are now visibly taking this problem seriously.

    It's saddening to read the hideously misguided posts here regarding amateur radio, but regardless of how anyone may feel about another's interests, the bottom line is that these PLT devices are being distributed with blatant disregard for basic EMC regulations, and a precedent must be set otherwise I can envisage the floodgates opening and a whole shed-load of non-compliant equipment being launched onto the market - if that happens, it won't be just the radio amateurs and shortwave broadcast listeners who will be affected.

    Incidentally, in the interests of educating some of the posters on here, radio amateurs represent only a small proportion of shortwave users who can potentially be affected by this prehistoric 'technology' known as PLT - even NATO has expressed concerns.

    Regulations are there for a good reason and must be enforced, and if our un-elected representative Ofcom won't enforce the law, then another course must be taken.

  40. Fred Bloggs 94

    @ anonymous coward, Sell what spectrum?

    "Ofcom should punish these luddites for thier law suit by selling off thier spectrum to someone who might actually use it or better still, revoke their license and bag the frequencies for some future technology."

    The spectrum is used by international agreement by users around the world, including broadcasters, maritime, aviation and military users, as well as amateurs and cb radio, so is NOT available for ANYONE to sell to anyone.

    Apart from that fact, WHO would want to buy a radio spectrum which has been made totally unusable by the proliferation of illegal plt/bpl devices, which splatter their evil digital hash everywhere.

    Alan - licenced amateur AND RSGB member.

  41. Gnomalarta

    About Time

    Good on the RSGB! Ofcom need to start Ofcomming and sort this QRM out. If allowed to carry on it won't just be radio amateurs and short wave listeners that suffer.

    Also let's not forget the UKQRM group who have been pushing this issue to the surface.



  42. g0ifi
    Thumb Up

    Re: Coward Re: RSGB and OFCOM

    Luddites, that's a laugh. I 'd suggest at least gaining a rudimentary understanding of something before you comment on it, Anonymous Coward. Amateur radio equipment these days makes your PC look like a wind-up gramophone. Let's broaden the affected section of the populace to where it is in reality, beyond hams, anyway. These illegal PLT devices wipe out broadcast frequencies, aeronautical frequencies, maritime frequencies, CB radio frequencies. It stomps on a whole range of frequencies between 2 and 30 mhz. It doesn't just make a slight buzzing noise or the odd crackle. PLT wipes it out.

    Maybe when Ofcom have punished the legitimate and qualified users of the spectrum, perhaps they can turn their attention to you, and flog off your internet bandwidth to someone who'll actually use it or better still, bag it for some future technology. Instead of letting people who don't have a bleeding clue what they're talking about use it to type spiteful, nonsensical rubbish.

  43. Trygve

    @John Murgatroyd

    "The problem is the manufacturers of some of the adaptors."

    No, the problem is that the UK is basically a shitty third-world country (with first-world price tags) where sensible and necessary laws and regulations are routinely ignored unless they can be used to extort money.

    e.g. Ofcom don't seem to give a toss about this issue, indicating they don't get any revenue from sales of standards-conforming kit or from non-compliance fines. If they did, they'd probably be waterboarding small children for info about dad's Powerline kit.

  44. Anonymous Coward

    RSGB dont like making friends...

    There are two sides, firstly scare tactics are all a bit NuLab.. Get over yourselves..

    "Non radio users may find it interesting that these Adaptors can interfere with wireless keyboards and mice.

    They dont like mains spikes which can make them stop working.

    Recently some users have found they reduce internet download speeds."

    ^comments like these are bitter nonsense fact is PLT works better than wireless it is winning market share because it works...

    Secondly The problems are not with OFCOM but with the laws...

    PLT devices are tested as they are, THEY DO NOT emit enough RF interferance themselves. The RF comes from the MAINS CABLES in the House acting as an aerial... hence it is the MAINS system Connected to the PLT that is at fault. so is that the USER or The Electrical system at fault?

    Remember it is not against the lay to own/buy/sell a radio transmitter it is againt the law to broadcast without licence. so one couild argue that the USER is at fault.

    the wiring in every house is different and so each case is different. and hence some are worse than others! until the laws are changed and houses are built with Ethernet or screened mains cables this problem is going to roll onwards.

  45. John Murgatroyd


    It is difficult to see the mains cables acting like anything else, since that is what they are used as.

    And not only within the house but to other houses as well: In fact, to all on the same side of the mains transformer.

    Practically everyone has slated PLT as a means of carrying data without interference:

    " From the communications engineering perspective, power cables are about as bad as it gets. The widely varying cable impedance and imhomogenous cable mixes installed in households, commercial buildings and industrial plants result in a transmission environment which exhibits enormous variations in impedance characteristics.

    This variability in cable impedance is further exacerbated by the widely differing high frequency behaviour of distribution panels, connectors, wall sockets, switches and other items of distribution hardware. Unlike hardware designed for RF or high speed applications, power hardware is optimised for robustness, low cost and low flammability. As a result, the impedance behaviour of such hardware is generally undefined. As wiring connections into such hardware do not impose impedance constraints, arbitrary birdsnests of connections are possible with the inevitable impact on impedance behaviour."

    "a) The cumulative noise field strength due to the PLT emissions may have a possible detrimental effect upon military HF radio communications and COMINT systems. This is particularly the case if In-House PLT systems should become widely popular. However, it should be noted here that the determination of the nature and the severity of any possible detrimental effect upon the military systems was outside the RTG’s expertise and ToR.

    b) The HF noise level in the vicinity of PLT installations has been considered in numerous other studies.

    One study concludes that interference from PLT to a station receiving low-level signals is likely at distances up to 460 m from a single Access PLT installation using overhead power lines. On the other hand, in sensitive receiver sites, the user generally can be assumed to have control over the vicinities, such that a protection radius of up to 1 km, without PLT installations, can be employed. In this case, the cumulative effect of long-distance propagation from a large number of PLT installations may be a more serious problem that requires careful consideration. Therefore, the RTG chose to focus on this less-studied problem"

    The above from a NATO document.

    Do I care ?

    Yes. PLT makes low-strength signals on 20 metres impossible to hear, and even strong signals are unpleasant to listen to.

    Fortunately, the plt devices seem unable to handle strong rf signals on other bands: 80 metres ssb kills them.

    Mind you, on another tack: BT has installed loads of their units (wifi) in the area...and all on channel 11.....six in the same street.....I understand they ain't workin' too well....

  46. Anonymous Coward
    Anonymous Coward

    Why have EMC laws if they are not enforced?

    Good luck to the RSGB.

    I work for a UK electronics manufacturer and every product we produce has to comply with the EMC regulations. It's an expensive process requiring careful design and attention to detail.

    If offcom continue to allow poorly designed PLT equipment to stay on the market, what is the point of having the EMC regulations at all?

    These PLT devices fail by over 30dB - a very wide margin. Put another way the level of interference that they generate is hundreds of times greater than the law allows.

    The sooner the law is enforced the better.

  47. Simon Batley

    This is not about 'Amateur Radio'

    Why or why does everyone go on about Amateur Radio. This has little if anything to do with Amateur radio. This is all about devices which appear to be illegal/non complaint jamming the reception of commercial short wave radio stations and as I have experieinced and heard from others, affecting broadband speeds - especially those of us in more rurual locations with overhead wires.

    Don't know about you lot - but when my broadband speed was hit by 20% speed reduction by a PLT user causing suspected intermods in the copper telephone wires as well as getting nose all across the short wave bands - I got Ofcom in to deal with it pretty sharpish and they did...... thank God.

    It appears we need a body like the RSGB to force Ofcom to realise what its right and left hand are doing....

  48. John Murgatroyd


    Its right and left hands are fully occupied: the right hand collects the cash and hands it to the left hand !

  49. Anonymous Coward
    Thumb Down

    Amateur Radio Operators?

    See Even the Machines Can't Wread Tit.

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  50. Anonymous Coward
    Black Helicopters


    Unfortunately, the truth of the matter is that it's not sufficient to "notch out" the amateur & broadcast bands, for the users of any PLT devices have no licence to transmit in any of the spectrum they use, at any power level, however miniscule (it makes no difference if it's 1 picowatt, or 1 kilowatt). This makes PLT illegal in any form that uses licensed spectrum.

    Now, go sign the petition at

    With a tin foil hat on, perhaps ofcon aren't doing anything about this, as it conveniently stops people listening to radio transmissions from other countries. Numbers stations anyone?

    I'll get my coat.

  51. Paul Widger

    Anomonous Coward ,you are wrong !

    You deny the statements I made regarding Powerline Adaptors.

    Well, I unlike you have tested them !

    My comments are based on observed facts as others can independently confirm.

    Suggest you get educated,then you would not be making ignorant comments.

  52. John Murgatroyd

    RSGB letter WITH measurement graphs.

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