> Why Ofcom is not fit for purpose  - The PLT issue <

PLT: PowerLine Telecoms Networking is a technology that can be used for computer networking. It is also proven by EMC experts to be extremely harmful to the radio spectrum by causing very severe radio interference. PowerLine Networking is being widely promoted by telecoms and computer companies - despite NOT complying with accepted technical standards known as Electromagnetic Compatibility (EMC). This technology is also referred to variously as PowerLine Telecoms - PLT, PowerLine Networking - PLN, PowerLine Adapters - PLA, HomePlug networking and sometimes as 'BPL'.  HomePlug adapters, PLA's, are the electronic devices used to create a network by transmitting wide-band radio signals all across the H.F. radio band. The most common and most disruptive adapters are the Comtrend type, supplied by British Telecom with their BT Vision service. If you are thinking of buying Powerline Networking Devices then DON'T ! > PLEASE RECONSIDER < "In simple terms - Ofcom might understand simple: It is not morally correct or acceptable for an 'unlicenced', 'wired'(therefore NOT wireless) communications system to be designed, sold, put into use, etc so as to wipeout an internationally used, licenced, important, finite resource. The 'Polluter Pays' seems very relevant here, and it is not as though this is new or has suddenly appeared overnight or even that it is JUST Radio Amateurs who are complaining, there is the EMC industry to mention just one."G8BLS PowerLine Networking adapters are being pushed by computer suppliers such as PC World and Maplin etc under many brand names including Belkin, Netgear, Devolo, Linksys etc. PowerLine Network Adapters cause terrible radio interference - they are completely unnecessary - the certainly do not conform with essential requirements of the UK's EMC regulations and some would argue that they might even be illegal in terms of the Wireless Telegraohy Act: NOTE: A better and more reliable can easily be established at a fraction of the cost of PLT by using a very simple and very cheap and reliable network cable.	Page 2     Page 3     Page 4
	PLT is BAD   :   find out more >
	The RSGB Spectrum Defence Fighting Fund
	Are YOU Suffering PLT interference ?
	BBC R&D White Paper on PLT
	I want to know how this interference can be allowed !
	Who REALLY regulates PLT in Britain ??
	Why is Maplin selling PLT ?
	Why Ofcom is not fit for purpose - The PLT issue
	Other Interference Switch Mode Power Supplies   &  Plasma Screens

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Are You Suffering PLT / HomePlug / BPL Interference?

More BPL Interference Information:

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Why Ofcom is not fit for purpose - The PLT issue

Text in blue are quotations from the OFCOM document 2.9.2009.

Ofcom’s  PLT  statement of  2nd  September this  year (www.ofcom.org.uk/radiocomms/ifi/enforcement/plt/) is a prime example of why it is not fit for purpose as a spectrum regulator and protector. Almost every line contains things that are economical with the truth, irrelevant, or spin – that is, when they are not blatant misdirection, or just plain insulting. Let’s look at a few quotes from it....

“Ofcom has exercised its enforcement functions under the EMC Regulations. Ofcom has investigated alleged breaches  of  the  EMC  regulations  resulting  from  the supply of Comtrend PLT apparatus by BT...... On the evidence,  Ofcom  has  not  so  far  found  that  there  is  a breach of the EMC essential requirements. Ofcom has therefore  decided  against  taking  further  enforcement action at this time”

But what “evidence” are they talking about? Of the technical evidence submitted in formal complaints by the UKQRM group (www.ukqrm.org)  and  by  the RSGB,  Ofcom  has  refused  to respond to any of it.

By  all  accounts  Ofcom  has  undertaken  no  technical  tests  or examined  the  Comtrend  PLT  devices  (the  ones  that  are  the subject  of  all  Ofcom’s  complaints  of  interference  from  PLT devices) against the points made in these complaints.

The  RSGB’s  complaint  (published  on  their  website, www.rsgb.org) was made on 31 July, just four weeks before Ofcom’s PLT statement. That’s hardly sufficient time for them to consider the evidence in detail and then write their response, if they could actually have been bothered to do so. Which they weren’t.

Indeed, their response does not even mention the two central points of RSGB’s complaint:

a)  Comtrend’s PLT products emit conducted noise at levels way above the limits in EN55022, the most relevant EMC product standard

b)  They rely for their EMC Declaration of Conformity on a discredited CISPR committee draft (CISPR/I/89) – simply a committee paper – never a published standard – which anyway was withdrawn several years ago.

Either of these plain and obvious facts should be enough to have their products immediately withdrawn from the entire EU market. That Ofcom have not done so brings the whole process of Single Market Compliance and CE marking into disrepute.

“Over  the  past  12  months  Ofcom  has  received  143 individual PLT interference complaints; all from radio enthusiasts... There are many other users of the HF Band including  long  range  aeronautical  and  oceanic communications,  the  Ministry  of  Defence  and international  broadcasters.  Ofcom  has  not  received complaints of interference to these services.”

Ofcom are apparently suggesting that complaints from radio enthusiasts are not as important as those from professional radio users. Would Ofcom have acted differently if there had been complaints  from  the  professionals? The  EMC  Directive  and the  UK’s  corresponding  2006  EMC  Regulations  do  not discriminate  in  this  way,  and  in  fact  the  EMC  Directive’s Recitals make it clear that Member States must actually protect amateur radio from “electromagnetic disturbance”.

Although professional radio users may not have complained of interference from PLT yet, you can be sure that they have been telling Ofcom how worried they are that it may happen!

As for being economical with the truth, Ofcom’s statement just happens not to mention that  the total number of complaints they have received about PLT interference, in just over a year, is  already their 4th  highest after complaints  about  lighting equipment; thermostats and aerial pre-amps which have been accumulating for several years.

Their statement also just happens not to mention that the rate at which they are receiving complaints of interference from PLT is far higher, per million units sold, than from any other technology.

“Evaluating the complaints received and the evidence so far obtained, Ofcom has concluded that there does not at present appear to be significant public harm arising from this situation.”

Perhaps Ofcom could point to the place in the 2006  EMC Regulations where it says that the number of interference complaints are a factor in determining whether something meets the Essential Requirements or not?  And perhaps they could also point to the place where it says that professional radio
users are more important than mere enthusiasts?

And where does the test of  “significant public harm” arise in the  EMC  Regulations?  None of these issues exist  anywhere other than in the fevered brains of Ofcom’s spin-doctors, who hope to convey the impression that they have some meaning – some relevance to the issue of interference from PLT, which of course they do not.

Ofcom  has  managed  to  get  BT  to  sort  out  many  of  the  143 reported problems with Comtrend PLT products. (BT sell the Comtrend devices bundled with their “BT Vision” product, so that customers don’t have to trail Ethernet cables from room to room, causing unsightly lumps in the carpets).

But the point is that the interference complaints are caused by the fact that these PLT products have a non-EMC-compliant design. If the PLT devices were compliant in the first place, they would most likely not have caused any interference.

“It is recognised that EMC compliant equipment may still, in certain circumstances, have the capacity to cause interference to other radio communications equipment. This  may  happen  due  to  the  manner  in  which  it  is installed or operated.”

Well, yes, but this is irrelevant. This is not a situation where a compliant  device  happens  to  cause  interference  to  a  radio receiver. Comtrend PLT devices are designed in such a way that they are almost certain to cause interference when operated in the vicinity of an HF (short-wave) receiver.

And as to “the manner in which they are installed” – how is this even possible? All you do is plug them in – how wrong can you get that?

“Is  there  an  EU  harmonised  standard  for  PLT?   No. The EU has not yet published a suitable harmonised standard for this type of apparatus.”

There is no standard specifically  for  PLT, but PLT is quite clearly  already  covered  by  EN  55022  –  whose  conducted emissions limits the Comtrend devices exceed by about 30dB.

And as for creating “a suitable harmonised standard for this type  of  apparatus”  –  it  seems  that  this  may  prove to be impossible (see later).

“Are  existing  EU  harmonised  standards  for  other products helpful?  Existing  harmonised  standards  are  helpful  only  to  a limited extent because they are not specifically intended for this type of equipment.”

Well, the information technology (IT) EMC standard, EN55022, does cover PLT (as mentioned above), because PLT devices are simply another kind of IT device. But what the PLT industry lobby wants is a standard that says that simply because a product is PLT, it is permitted to emit 1,000 times more radio-frequency noise  into  the  mains  network  than  anything  else  is  legally allowed to emit.

If  such  a  standard  was  created,  you  can  be  sure  that  other powerful industry lobbies would very quickly insist on having their own EMC standards that allowed them to emit 30dB more noise into the mains distribution too.

After all, if PLT products can emit noise at this high level and yet enjoy a presumption of conformity to the EMC Directive, why not their products?  Then they could remove all their mains filters and save a very great deal of money.

“Ofcom believes the electromagnetic disturbance produced by this technology is an inevitable by-product of  its  operation and not  attributed to poor design or manufacturing.”

This is a perfectly correct statement!   Only not in the way that Ofcom wants it to appear to the reader. The Comtrend PLT design is not at all “poor” and neither is
their manufacturing. Both are perfectly competently done. It is just that the design of Comtrend’s PLT products is intended to put signals onto the mains distribution network at 1,000 times the maximum level required to protect the radio spectrum from interference. So of course “the electromagnetic disturbance produced by this technology is an inevitable by-product of its operation”!

Aren’t Ofcom’s spinmeisters clever? One has to be impressed!

But since Ofcom are employing such clever people, why doesn’t it employ them to do something a little more useful, perhaps something that contributes to Ofcom’s legal duty of protecting the radio spectrum?

For example, they might apply their huge and powerful brains to noticing that Comtrend’s EMC Declarations of Conformity are complete eyewash.

“Would the development of an EU standard for PLT help?  Yes. At  present,  testing  and  assessment  takes  place against a backdrop of wider technical uncertainty than is normally the case and there is an increase in the take-up of this apparatus across Europe. The  development  of  such  a  standard  would  be  an
important  step.  The  standard  could  be  used  by manufacturers  and  Notified  Bodies  to  assess performance against recognised benchmarked values. If the apparatus complied with the harmonised standard under  the  Regulations,  there  would  be  a  legal presumption  that  the  apparatus  met  the  essential requirements.”

There is work ongoing in CISPR/I to try to create a product specific  standard  for  PLT  devices,  but  it  suffers  from  huge difficulties because the opposing factions (PLT manufacturers versus almost everyone else) are each determined to get their own way, and there is no middle ground.

Either  PLT  emits  at  1000  times  the  emissions  limits,  or  it complies with those limits and doesn’t work. (At  least,  this  is  the  entrenched  position  taken  by  the  PLT industry, although recent work has shown they can emit at the limits given in EN 55022 (the “CISPR limits”) and still achieve data rates that would satisfy the vast majority of their market. But the PLT Industry appears to believe that because it spends so much on lobbying, it should be able to get just exactly what it  wants.  Unfortunately,  because  the  way  the  European Commission operates, this is quite a reasonable belief.)

Anyway, an “EU standard for PLT” is a complete non sequitur. There is no need for any product to declare compliance to any standard. A technical assessment for EMC compliance purposes can use Harmonised Standards, or not, as the manufacturer sees fit. So why all this fuss about standards?

Ofcom  states  that  it  believes  that  the  electromagnetic disturbance is an inevitable by-product of the operation of PLT devices – which is actually an admission of non-compliance! Since  they  don’t  appear  to  understand  this  basic  point,  we suggest  Ofcom  bothers  to  actually  read  the  Essential Requirements in the UK’s EMC Regulations – where they will see  that  apparatus  is  simply  not  permitted  to  be  designed/constructed in a way that interferes with other equipment, and especially not with radio reception.

The fact is – as many have said – broadband PLT (“Greedy PLT” as it is coming to be known) such the Comtrend products, uses an inappropriate technology. It deliberately produces a lot of  electromagnetic  energy,  then  tries  to  couple  it  into  an unknown impedance of unbalanced, unscreened cables (i.e. the mains distribution  network  in  a  house). Any  radio  engineer would call that a recipe for disaster. And it is.

This is why there is all this fuss about creating an “EU standard for  PLT”.  Such  a  standard  would  effectively  authorise  the Greedy PLT industry to claim presumption of conformity and legally affix the CE marking to their horribly noisy (by design) products, even though they could not possibly comply with the Essential Requirements.

A final piece of nonsense and [Ofcom] obfuscation:

“The  EU  Commission  is  aware  of  concerns  resulting from the proliferation of PLT in the EU and in response, issued a mandate (M/313) to the European Committee for  Electrotechnical  Standardisation  (CENELEC)  to produce a PLT harmonised standard”

M313 is totally irrelevant to the compliance of PLT devices. In fact, it specifically excludes them.  Instead, M313 concerns the compliance of complete data networks.

Spin,  once  again.  Or  is  it  obfuscation?  Whatever, it is intentionally misleading. It is also offensive and/or insulting, because it assumes that readers are so ignorant that they can’t tell the difference between a network and a device that connects to it.

M313 has been worked on for 10 years with no signs of success. There has been some further work on it recently, but agreement looks as far off as ever, and even  then  many  commentators suggest that it could never be applied to PLT networks, simply because – by their very nature – most mains networks pre-date the EMC Directive and were never installed for the purpose of carrying data in the first place.

Should we be surprised by all the spin, smokescreening, whitewash, eyewash, hogwash and (no doubt) many other kinds of wash, in Ofcom’s PLT statement of the 2 nd  September 2009?

Well,  probably  not,  because  Ofcom  is  manifestly  unfit  for purpose.  We  should  probably expect that  –  given  its contradictory  roles  –  something had  to  give,  and  the  PLT statement is just a result of that failure to reconcile opposites.

Ofcom was conceived and created to fill the role of a single regulator to oversee the apparently converging fields of broadcasting, telecomms and spectrum protection. As far as spectrum protection is concerned, Ofcom is required to be both poacher and gamekeeper. What has happened is that the needs of telecoms and broadband (the spectrum poaching role) have prevailed over  proper  management of  the spectrum  (the gamekeeper role).


Someone who has long worked in Government in the UK, and who  shall  remain  nameless  (for  obvious  reasons),  wrote  the following in a private email recently:

“Having worked in Ofcom I know how that works too. Created by the present Government, it is rather like an out-of-control  child  that  sometimes  attacks  its  own parents  and  ignores  anything  it  doesn’t  like.  It  is dominated by media luvvies and telecoms economists, with spectrum management coming a poor last (just one fact, out of many: they have reduced EMC enforcement / interference  staff  by  60%  since  taking  that  duty  over from the Radiocommunications Agency). And it has its  own  effective  spin  machine  that  –  like  the  whole organisation – is not accountable to anyone, which is not surprising when you realise that both of its Chief Executives have been No.10 spin-doctors themselves!”

The  only  real,  sustainable,  sensible  answer  is  to  remove  all EMC regulatory duties from Ofcom and give them to a separate, independent Regulator, who is able to focus on managing the radio  spectrum  without  being  dominated  by  big  business interests.



The above is an article from The EMC Journal. It must be said that the the field engineers and technical staff working for Ofcom no doubt do a very good job but who are, unfortunately, completely powerless in the face of the cynical misinformation from their cringeworthy Ofcom masters and the lying labour government spin merchants.

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PLT / BPL Interference Evaluation Tool

Broadband over Power Lines is technology for carriage of high speed data, principally for Internet Access, over the existing power line network.

Current BPL technology works by conduction of signals in the radio frequency spectrum up to about 100MHz.
Existing power lines networks are not ideal RF transmission networks, they will radiate radio frequency energy causing interference to radiocommunications services, and they will be susceptible to interference from nearby transmitters - radio or otherwise.

The European Committee for Electrotechnical Standardisation, CENELEC, are developing a standard for "Electromagnetic emissions from access powerline communications networks". Access powerline communications networks are commonly termed Broadband over Power Lines or BPL.

The proposed CENELEC standard does not automatically apply globally, though countries like Australia draw heavily on international standards, such as CENELEC's for their own jurisdiction.

This proposed standard would set limits for the conducted energy and radiated energy of BPL systems. The radiation limit is specified for example as a field strength in dBuA/m in a measurement bandwidth at a specified distance on particular frequency, and its impact will not be immediately apparent to most radio users.

Do you know what the impact of +4dBuA/m in 9KHz at 3m is on your receiver?

The BPL Interference Evaluation Tool allows evaluation of the impact of BPL interference under the proposed CENELEC standard given a set of location / application specific parameters.

Go to the BPL Interference Evaluation Tool at www.vk1od.net/bpl and enter the details for your site and discover the impact.

If you understand the potential impact, you will understand that BPL is the most serious risk that faces amateur radio today.

We, as a community seem absorbed with club level issues and small minded parochial thinking when a concerted national and international level approach is needed, and needed now.

Owen Duffy, VK1OD      [ http://www.southgatearc.org/news/october/bpl_calculator.htm ]

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HomePlug Interference - Yours Soon?

Severe interference from PLT / B.T. HomePlug (BPL) Adapters threaten to wipe out our hobby in the near future. The whole of the H.F. (shortwave) radio band could be potentially lost. That means Amateur Radio, citizens band (CB) radio and the ability to receive short wave broadcast stations.

This Broadband By PowerLine technology is also known as Power Line Telecom (PLT), Power Line Networking (PLN) and Power Line Communication (PLC). It is marketed as ‘Home Plug’ by branding and is supported by a 'bully-boy' pressure group of large self interested companies called The HomePlug Alliance.

Such Broadband by Power Line devices distribute broadband internet network connections via un-shielded mains wiring using a broad range of the radio spectrum between approximately 2 MHz to 30 MHz. This is the H.F. “short wave” band. The use of un-shielded household mains wiring to distribute these BPL signals effectively allows it to act as a large radio transmitting aerial. The signals from BPL devices can therefore be received for hundreds of metres around a property and will therefore cause severe interference to, or entirely obliterate the reception of radio services on the H.F. band to legitimate and licensed users.

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More QRM Problems


Switch Mode Power Supplies - Switch mode power supplies are typically found in computers (PC's and laptops), but are also supplied as an inexpensive power solution for many other mains powered electronic devices and gadgets. A switch mode power supply does not necessarily have to cause RF interference, but many switch mode PSU's are built down to the lowest possible price and to achieve a low production cost, many if not all the necessary filtering components such as capacitors and toroid inductors are omitted. These poorly designed and cheaply made switch mode PSU's are a potential source for seriously problematical amounts of RF pollution across long wave, medium wave, short wave and VHF bands.

I have found from experience that the switch mode power supplies that come with many of the cheaper PC cases and towers can create rather a lot of RF noise across all bands. I have used the 'Hiper' brand of ATX PSU's previously and found them to be fairly quiet as far as RF QRM is concerned. I therefore fitted a 'Hiper' brand HPU4S425 Silent 425 Watt PSU in a recently rebuilt PC help minimize RF noise from my PC's. Supplied by CCL Computers - my regular PC components supplier.

Links:
http://www.rsgb.org/emc/pdfs/leaflets/emc4interferencetoamateurreceptionmembers.pdf

http://www.rsgb.org/emc/pdfs/plt/radcom02plt.pdf



Plasma Screen Televisions - Many plasmas screens, the current fad in television viewing, cause enormous amounts of radio frequency interference across the LF, MF, HF bands and beyond. The RSGB EMC Committee is researching interference caused by plasma TV and would like to hear from those suffering interference from a plasma TV in the HF bands. Contact the Radio Society of Great Britain - http://www.rsgb.org

It is alleged that plasma televisions manufactured by Panasonic cause far worse radio interference (spectrum pollution) than other manufacturers such as Sony. I have no information to back this up, but if Panasonic plasma televisions are not EMC compliant then it would be worth investigating further should you be considering the purchase of such a television. 

Other links:
http://www.rsgb.org/emc/pdfs/leaflets/emc09inbound.pdf

http://www.rsgb.org/scienceweek/scienceweek.....pdf

http://www.transmission1.co.uk/index.php?name=PNphpBB2&file=viewtopic&p=31797

http://www.eham.net/articles/4285