David Mowat has demonstrated that even MPs can't get a straight answer on powerline networking, although Ofcom has refined its initial explanation that not enough people care. The MP for Warrington South posed a question to the Minister for Business, Innovation and Skills, asking about future regulation of Power Line …
I think that you will find that it is now called Radio 4 Extra.
oh hai ofcom can i tell you about something thats going to be a big problem in 5 years?
no, we don't want to hear about it until it is already a big problem, at which point we will be powerless to do anything anyway, go away.
so, to direct action (in thought experiment, at least)
build some fantastically flaky PLN kit that produces so much interference that it, in effect, works like an aggressive jamming signal. Donate this (ahem) "spare" kit to someone living next to a residence of someone with a bit of clout, and see if anything happens.
So what I take away from this piece of news is that if we all shaved the world would be a less grumpy place. Everyone! To your razors!
But wet shave, because otherwise an increase in the use of electric razors will generate more interference!
Powerline networking or Radio 7?
Tough choice, hmmmmmm.....
I'll take the powerline networking thanks, Bob.
Yes, but it's...
not Radio 7 or PLT, it's Radio 7 for all your neighbours or PLT for you.
Thanks for being such a selfish idiot.
grumble....moan...typical of Thatcher's children....whine.....
21st century politics, la, la, la where not listening.
Well at least I get to decide how I vote for Christmas which is all important and not actaully who I vote for as there all the same. What noise do Turkeys make?
How you vote determines who the candidates are
Not that AV will change anything much, but changing the rules of who wins will decide what sort of people stand - if you want better candidates to vote for, then you need a system where better candidates win and incompetent lying buffoons lose. At the moment, liars win elections, which is why candidates lie.
Of course AV is a quantum leap. That is, it's the smallest possible change to the system.
Hey, there's a Referendum!
Just think, we have a ballot on Thursday that they have to listen to.
Me, I reckon, from the way the politicians are already squealing, that a "Yes" vote is going to be more fun.
Smoke and Mirrors
"Interference is everywhere and, as Ofcom's new statement points out, we have no right to expect clean radio spectrum"
This confuses two issues as one. Yes - interference is everywhere - the point is, a manufactured device which creates radio waves should not create these radio signals on a frequency which is disruptive to other devices.
For example - I'm not allowed to build and use a VHF jammer which disrupts radio transmissions.
Yet it seems OFCOM fail to understand that building a network device which spews out exactly this type of radio interference, that this is somehow acceptable since it does so 'by accident' - this is NOT an excuse for allowing it.
So either they confuse deliberately, or they're incompetent.
In either case, they're useless and worse. They're not doing the job they're supposed to do.
Why yes, this does make my boot itch something fierce.
Yes Ofcom, interference exists.....
....and mostly it is not time-continuous in nature, does not cover a wide frequency range simultaneously and is not at a level that precludes the operation of equipment in reasonable (or even close) proximity. PLT interference however can easily be all of these things at once which makes it a very different beast indeed.
BTW I think you need to have an old grey-bearded geek icon, especially for people like me who have held amateur radio licences for over 32 years, and have an old grey beard to go with the licence.
In addition to the interference issue
Powerline networking is unable to achieve the bandwidth of a fiber link. It's a bad technology for what it's being used for: delivery of internet bandwidth to the individual user. It requires expensive and large isolators,more closely located repeaters and high voltage precautions for maintenance. It's fundamentally a bad technology, kept alive only by "entrepreneurs" seeking to make a bundle of money on a scheme that can't compete.
Think of DSL...it can't compete in terms of bandwidth or distance with fiber or coax. BPL is DSL on steroids (and high voltage)...you're going up against the laws of physics, powerlines weren't built to handle high data rates, and so, not surprisingly, they do so extremely poorly.
@Peter Simpson 1
What are you going on about here? We're not talking about delivering internet bandwidth to end users, but end users connecting devices in their homes. A couple of wall warts in different rooms to connect devices to their home networks, no long distance delivery of internet bandwidth to homes.
Different Types of Interference
There are different types of interference. Broadly you could say there are two types, that which you can easilly do something about and that which you can't. PLT would seem to fall into the former category, but for some reason Ofcon seem to want us to believe that it's in the latter.
PLT is not, for example, a force of nature. We had a thunderstorm up here the other day and it played hell with the TV signal. Especially when it hit the transmitter. I'm not going to suggest that Ofcom or anybody else should try to ban thunderstorms because they mess with Freeview. However... There are PLT devices out there that do not comply with current regulations and should not, therefore, be legal for sale. This is a different matter. Ofcom, or whoever happens to be in charge these days, should be taking action against the companies selling, importing and/or manufacturing these devices. They should also be taking action against people using them.
In the latter case we're not talking about fines or the like, just some gentle advice. People may be causing interference without intending to do so, or indeed without knowing they are doing so. In these cases the usual line is to track them down, explain the situation, ask them to stop and offer some advice on how to achieve their intended ends without causing inteference.
Ofcom do just that where other kit is causing interference so why are they so reticent to do something about PLT devices. Indeed why are they so reluctant to even admit PLT devices commonly cause interference.
(often bearded) radio amateurs
Well - I am not bearded for starters - and I am a Full UK Radio Amateur and am only 30!
I have been licenced for over 15 years! I Have vast experience in Electronics, IT and in the Communications world.
I think a lot of this is down to OFCOM knowing there is an issue - but as there is far too much kit out there now already, plus for them to back track would prove costly to both them and people like BT that supply one of the worst PLA kits' such as the COMTREND units.
The reason they keep giving duff answers is they know they are wrong and if proven to be by giving a submission of guilt, could and would prove costly!
I think you will find that more people would complain if they understood what the underlying issues were; but mere mortals may not understand by not being technical like some of us, or they merely may not know who to complain too!
There are 60,000 radio amateurs in the UK
272 have complained to ofcom. Presumably the other 59,728 have some experience in sorting out local QRM themselves without having recourse to cry to the regulator or the Radio Society of Good Buddies.
I dare say some of them are even old enough to grow beards, have been licenced slightly longer than 15 minutes and didn't have their callsigns handed to them on a plate ;-)
....that no one has had an accurate estimate of the number of actual radio amateurs for a long time, plenty of licensees have more than one licence due to the relatively recent multi-tiered licence arrangements.
That means that the statistics you quote are probably optimistic in terms of lack of interference.
In the last ten conversations (not on air) that I have had with other radio amateurs, PLT has been a subject of discussion in every single one of them. So those licensed are very aware of the problem.
As for the ability of those affected to ameliorate the interference when it is present, I think that in many cases that's a bit of a pipe dream, don't you?
Not a Ham, just a SWL. I complained to ofcom, got a prompt phone-call from someone who gave the distinct impression that he both A- Gave a toss and B- Knew what he was talking about, he said Id be getting a call back from their triage team regarding an investigation.
The next day I got an e-mail that can be summarised thus:
"this is the BBC's problem, here is a link their troubleshooting guide, case closed, piss off"
This was a huge disappointment, I know there are at least 3 BT homehubs within 50 yards (I know a homehub does not a PLN make, but they are prime suspects) and I was of the understanding that the BBC no longer broadcasts on shortwave for domestic consumption, so I don't really see what this has to do with them at all.
All I can hope is that this gets chalked up as another PLT complaint, and not just some guy moaning that his radio doesn't work.
Kind of half useless
... at least the pair I tried: these needed to be connected to the same phase to work. Anything larger than a small apartment is likely to have the sockets distributed between different phases. In a small apartment wi-fi would usually work great anyway and be more convenient and probably as speedy.
I really doubt that many houses are on more than one phase. It can cause all sorts of earthing problems, some quite dangerous.
I worked at a REC (Regional Electricity Company) for a while, and it was explained to me that in most streets you end up with the phases being alternated down a street, so you are rarely on the same phase as either of your neighbours.
A single phase is quite capable of delivering the 60-100A that will be more than most dwellings need. You can tell by finding the electricity meter in your house. If you have a single meter with a single (normally red, and quite thick) wire connected on the input side, you are on a single phase.
I have PL set up in my house, and we have it working through the all three floors of the house, through several breaker boxes which are only connected together at the main live feed into the house. Some of the parts get better speed, however. Most of mine are eBuyer special 85Mb/s Turbo mode devices, about as cheap as I could buy.
When setting up some PA kit at my University hall of residence, we had a persistent buzz we could not get rid of. We traced it down to having different phases and earths on each side of the dining hall, and we measured more than 100V AC between the earth pins of sockets on each side of the hall. This scared me quite a lot.
I would imagine anything smaller than a large mansion would be single phase. I think you are speaking of the 'legs' of the US split-phase system. Both legs are on the same phase. Power line comms don't work well between these legs without a bridge, usually placed in the breaker panel.
Not that any of this pertains to the article, since that's about the UK which enjoys a far more sensible residential power system.
Why PLT may not work
PLT only works when other devices (e.g.PC PSUs, wall warts etc) DO comply with the 2006 EMC regulations otherwise there are problems. Mains wiring was never intended for RF (electromagnetic) energy but that is just what PLT does do - an aspect that Ofcom fail to take into account and so allow statute to be breached.
PLT is not limited to one house, it will conduct beyond the meter - its limit is your local substation -that's the reality of this piece of outdated polluting 'technology'.
It could be worse
"... we measured more than 100V AC between the earth pins of sockets on each side of the hall ..."
It can be a lot worse than that. I was installing networks at a US military base back in the 1980s. The building in question was originally built in the first decade of the 20th century. The other half of it was added during WW2. The voltage difference between earths/grounds on opposite walls of the same flippin' room were over 400VAC. They weren't even fed from the same substation. And God help you if you didn't have a voltage isolation unit in your mains supply when a battleship or aircraft carrier switched between on-board and land power.
true for the uk
I understand that 3 phase supplies to domestic services are/were pretty common in Germany. Although as you point out usually you'd have 1 phase to all your power points etc and a 3 phase connection in a utility room/garage/workshop
"we measured more than 100V AC between the earth pins of sockets on each side of the hall."
Why would the rings being on different phases affect the earth potential. The earth in the building will be bonded to the physical earth usually by hefty earth spikes and through the water pipes. The risk with different phases in the same location is that you will get large potential differences between the live (not earth) of the two different phases. So if you did get 100V between the earths on the two rings then it was nothing to do with their being on different phases, but a serious wiring problem within your building. Most likely that one of the earths was not actually earthed, but possibly connected to neutral.
Think about your local substation where you live. There are three phases and and a neutral which is eathed at the substation. Which is where, I think, you are getting confused about the whole earthing issue.
Different potentials on the earth in a ring.
I don't know exactly how the rings were arranged in the building (I was a mere student, not one of the staff), and I admit that there could have been a wiring fault, but this is what we measured. It may also be that the neutrals of the different phases were not tied together correctly. The hall comprised of a number of different buildings up the street, so may have had separate single phase installations at some time in the past which may explain it not being a proper three-phase installation.
This was 30 years ago, and the building was a lot older than that. I have no idea about the current capacity of that situation, I didn't want to put a load across it to measure the current. It may have just been an earth-leakage problem in some equipment attached to one of the rings. It was close to the kitchen.
Each phase could also have a different earth, with no common connection through a conductor. The earth itself is not a conductor, so it is perfectly possible to get local variations in earth potential.
Law and Loop holes.
The problem with PLT kit is that it causes the mains wiring to radiate RF, NOT the PLT box itself. This is a legal Grey area as technically it is the Mains that is at Fault not the PLT box. which when tested in an isolated chamber (isolated from the mains!) it complies with the regulations.
What is needed is a change in the testing regime such that any device that causes connected systems to radiate not just any device that radiates.
Which is why.....
....testing to EN55022 requires the use of a mains simulator, the LCN or Line Coupling Network of specified conductor pair imbalance.
or a change to the wiring regs to requre all mains wiring be made from screened cables :-)
the perfect solution.
ofcom can be as crap/corupt as they like, plt can fuck off and stay fucked off.
mines the one with Screened Cable Mfr shares in the pocket
everyone keeps forgetting !!!
OFFCOM is now nothing more than a sales team !
the only complaints procedure they have is to chuck all the hate mail into a big box and when its full post it to the DTi and hope none of it comes back and bites them!
So what's the point?
Which begs the question, 'what the hell are ofcom for?'
Are they merely a drain on taxpayers money?
> Which begs the question, 'what the hell are ofcom for?'
To appear to be doing "something"
...something the EU courts have finally wised up to.
If we have no right to expect clean radio spectrum, then why do I earn a living working as an EMC engineer? There are standards for a reason and this is one of them. Just because there is no directly applicable standard that applies to PLT, doesnt mean its not a problem. Is this just a case of looking the other way?
...has failed so far, mainly because the committee was forced to try to create a standard that allowed the existing flawed products to be ruled legal. The process did not reach a sensible conclusion and has been referred back to the institutions to try again.
I suspect that any attempt to make this work with signals over noisy mains wiring will fail, but we'll have to see what gyrations are tried to achieve something that can be agreed on.
PLN: rubbish anyway
My desk is in the room next to my router and across an open hallway, which makes running ethernet cleanly kind of a pain. So for a long time I used wireless, but it was always slightly flaky and I could never get 802.11n speeds to really work, so I went and got a PLN kit. Turned out it worked great...except that it would corrupt the odd packet, apparently unrecoverably. Any download of 500MB would have about a 50:50 chance of being corrupt, whatever download manager I used. Above that size the odds got worse, obviously. Makes it pretty damn useless when I spend a lot of my time downloading and testing large Linux distro ISO images. (Also hardly inspires confidence in your system updates).
So I spent an hour running a 50 foot ethernet cable around a doorframe and across the ceiling instead. Works out much better in the long run...
...but I'm going to have to call BS on that. The protocols used in networking are generally error correcting, because the very nature of networking and the internet you will always get errors. Do a bit of network sniffing the next time you're doing a big downloads (even MS Netmon will do) and you'll see errors and requests for retransmits and the like. Errors like this do not actually cause corrupted files, they just slow the download. You'll always get errors when downloading a large file from the other side of the world, when you get lots of errors you won't necessarilly get a corrupt file you'll just get a slow download.
See title. I've been doing this for a while. When the sha256sum doesn't match, you have got yourself a corrupted download.
I agree with the AC
If the files are corrupt, it is probably something other than the media or transport layer of the network that is at fault. If you are using TCP/IP, then you should get an error free stream of packets, because the TCP layer does packet checksum and retransmission. I suppose that it is just possible that a corrupted packet actually has the same checksum as the original, as the 16 bit checksum on TCP packets is not especially robust, but I do not know how likely that is.
Anybody any idea?
Divide and ignore
Since last July, Ofcom only handle interference to licenced radio; ham, business radio etc, while all 'domestic' interference to TV and Radio is now handled by the BBC, who escalate cases back to Ofcom only when they cannot resolve them themselves.
Radio amateurs and the like are relatively few and far between, but are likely to at least be able to take a stab at what's causing the problem, while those who pay Ofcom for a licence will probably have it taken seriously in any case. Many amateurs, having taken a casual look at Ofcom's general utility, will simply not bother reporting interference unless it's intolerable as they know pretty well nothing will happen except they'll be chalked up as an interference case. So Ofcom's numbers are probably way low in any case.
Joe Public, most of whose case are now dealt with by the BBC, are unlikely to be anywhere near as clued up on why (or even if) there is interference to Eastenders. They are equally likely to have a poor view of the interference reporting process, and just won't bother.
I'd reckon the collective figures for interference of all kinds including PLT will be very, very low and unrepresentative of the scale of the problem in any case. Ofcom's obsessive "evidence based" approach to everything weds them to the notion of the numbers they have being the gospel truth and as they stand, insignificant. The fact that BT's devices seem to be the worst culprits only encourages them to look the other way - they have a long track record on being soft on BT.
A flick through various ISP forums will show just how clued up people are on electrical noise in general. A very high proportion of 'difficult' broadband problems look very much like REIN issues if you have the experience, yet are dismissed as such routinely. It's hardly a great surprise complaint numbers are not high.
Since taking over from its predecessors Ofcom has shown far more interest in market forces than technical expertise, and this probably reflects in its view of radio amateurs as bearded troublemakers (bad) and PLT kit as 'what people want' (good). Anything that doesn't fit the Ofcom-centric view of the world can be comfortably ignored as long as the noisy types remain bearded, the numbers stay low enough and the public can be fobbed off.
Joe Public, DAB and PLT
"Joe Public, most of whose case are now dealt with by the BBC, are unlikely to be anywhere near as clued up on why (or even if) there is interference to Eastenders."
When it comes to interference on DAB I suspect that Joe Public won't complain at all because there is so much negative publicity around DAB. So JP goes out and buys a nice new DAB radio and sticks it in the kitchen and gets loads of interference. Is he going to complain to the BBC or is he going to take it back to Argos and tell them he can't get DAB in his house?
Lets be fair he probably doesn't even know he can complain to the BBC about general interference.
Quick and Easy
Got the cheap fast ones off Amazon? eBuyer?
They just work.
That is all.
They may just work for you. This whole affair is about Social Responsibility.
Have a care for the consequences to others of your apparently highly selfish decision.
Not your problem?
My van would run better if I took the silencer off the exhaust. But I don't think you would appreciate how much nicer this is for me when I'm driving down your street at 2 in the morning.
Time for a Tin-Foil Hat
As we haven't yet had the obvious conspiracy theory, I feel honour bound to post it.
1. The Home Office has a Plan for the complete control of the thoughts of all UK residents,
2. Listening to internet streamed audio (aka Internet Radio) causes the ISPs to record the IP address of those receiving the stream, and the times at which it was received,
3. Records from 2 are available on demand by any investigator authorised under RIPA, who can therefore make deductions about the IP address user's preferences and opinions,
4. Arbitrary web pages can readily be forbidden to UK subscribers using the existing infrastructure of the Internet Watch Foundation,
5. There is continued pressure from Government to turn all broadcast radio and TV transmissions to digital, even with a clear lack of demand (or outright opposition),
6. Digital broadcasts have the capability to be encrypted,
7. Encrypted digital broadcast streams have the ability to turn individual cards/receivers on or off, entirely under the control of the transmitting organisation (eg the manner by which Sky enforce payment),
8. Analogue signals can be more readily decoded under adverse transmission conditions,
9. Analogue radio and TV transmissions are significantly more difficult to encrypt,
10. Low power transmissions on many frequencies are sufficient for communications around the world,
11. Despite the "significant" investment by the BBC in its fleet of "Detector Vans", it remains difficult to know when a receiver is operating, where, and what is being received,
12. Detection of operating receivers can only be made in the vicinity of the receiver, not in a central data centre or exchange,
it is Therefore Concluded that:
13. The indifference by OfCom to a proven problem is deliberate,
14. The inability to formulate, much less enforce, a technical standard to ensure continued long distance use of frequencies between 1.5 MHz and 150 MHz is deliberate,
15. It is the defined agenda of OfCom is to make every individual communication by every British resident subject to an individual permissioning, recording and censuring scheme (aka Big Brother), and to destroy all other communications methods.
Now, the next question is what to do about it?
"Interference is everywhere and, as Ofcom's new statement points out, we have no right to expect clean radio spectrum."
It's odd then that they are so keen to take action against sources of interference other than PLTs. I just can't figure out what it is that makes Ofcom so defensive of PLT. Is there some vested interest here?
This is a much wider problem, for example Sky found out the hard way that my neighbours wireless home alarm was interfering with my sat reception, dozens of channels in one transponder knocked out even sent an engineer with a fancy spectrum analyser to figure it out.
They then had to move the dish to the far side of the house, install a mast etc just to avoid it. Nothing to do with powerline networking at all.
Also while some bearded HAMs complain, they themselves are also sometimes the source of interference to other peoples' use of services. HAMs have so many bands to choose from, surely they can adapt a little. After all part of being a HAM is the challenge of overcoming technical difficulties.
I just can't see how people expect Ofcom to deal with all these problems. It's like trying to plug holes on an already sinking ship. You'd need serious money, or massive restrictions, to police all of this.
AFAIK your neighbour's wireless alarm should not (legally) be operating on any of the frequencies that Sky uses. If it is operating on those frequencies then your neighbour is breaking the law and you should be reporting him. If it is causing inteference on those fequencies then it's less clear cut, but basically it is still a legal matter.
However you look at it in your position I would not have paid to have the dish moved, I would have made the neighbour either pay for the work or get their alarm sorted.
There is a lot of talk about interference when there is no unreasonable interference. I swapped ISPs last year and got a new router as part of the deal. I noticed within days that the wireless would slow to a crawl although not generally drop. The ISP told me it was interference from some nearby source. So to check I plugged in my old router and set it to the same channel. No problems at all for a week. As soon as I reverted to the new router I had loads of issues. I contacted the new ISP who told me that the new router was quite susceptible to interference. So I told them it wasn't for purpose and asked for a replacement and was told that since it was a free router it wasn't covered by the sale of goods act. I pointed out that since it was covered by my contract it was not free. In the end they sent me another router which has had no problems. The curious thing is its the same model of router so their comment about that model being "susceptible to interference" was BS. Just a faulty bit of kit.
Anyway the way I read the rules I thought kit had to do two things when it came to interference. 1. It must not interfere with other kit. 2. It must accept reasonable levels of inteferference from other kit.
It "kills DAB" you say?
I shall be buying one forthwith.