Why are Al Qaida objecting to powerlines?
Interference from PLT was debated in the UK Commons last night. At least an attempt was made to do so: the BIS minister preferred instead to ignore the questions and focus on the bearded minority. The matter was raised by Mark Lancaster, MP for Milton Keynes North, as an adjournment debate comprising a statement and response …
Well, someone has to be the grammar pedant.
Sadly, this is going to have an impact of 10^-googolplex. Our only saviour would be the Big Stick From Brussels, but l'Affaire Phorm and DNA retention policy teach us that even that isn't really too effective
J (RA but not bearded - well, only 2 days' stubble!)
You have completely missed the point...
I am both a PLT user and a radio ham, as someone with a vague understanding about radio transmission I choose to use well build and tested PLT kit that doesn't seem to affect radio reception.
OFCOM *should* be doing something about the crap kit that causes interference right across and out of the top of the ham bands...
Oh and obviously it matters not to you because they too are a tiny minority but the military use most of the HF bands, hams have a tiny slice... so shove it and take your pointy ears with you freak.
"I am both a PLT user and a radio ham, as someone with a vague understanding about radio transmission I choose to use well build and tested PLT kit that doesn't seem to affect radio reception."
Sorry, but no-one in UKQRM has found that to be true. Have you tried listening outside of the Amateur bands, or tried using 5MHz? Which modes are you using that are not affected by PLT? What "well built and tested" kit are you using? Care to post the make, model, etc.?
That's the definition of a corporatistic dictatorship, i.e., fascism.
If you'd actually seen any Star Trek instead of read/heard about them, you'd know that almost every single episode goes out of its way to reconsile the two if not boldly defending the individual. Whatever one of their characters may every once in a while say --- that character is shown to be smart but not wise/human.
Now bite my shiny metal ass, let's see some decent SF instead.
"The needs of the many..." was said by Spock when he sacrificed his life to save the Enterprise from destruction. The moral message from Star Trek has always been to protect the individual from the tyranny of the majority. Did you miss that point or have you strayed across from the parallel evil universe where Kirk says it to Spock as he locks him in the radiation-flooded engine room?
"Let's revisit when something important is impacted." Some important things are impacted - standards compliance and the law.
For the record, I don't use HAM or PLT, I just don't like minority groups getting shoved around, especially when they were there first.
...to make a very minor correction.
The needs of the many (all RF users) outweigh the needs of the few (PLT users).
and by 'all RF users' I include anyone who has/uses at least one of the following :
Remote car lock
Wireless Central Heating controller
Remote control toy car
Weather station with remote sensors
By all means revisit it when any of these things does not work in your home. Who you gonna complain to? Ofcom? Good luck with that.
Hi, the PLT affects users of HF so you are looking at military, certain PMR, AM radio, radio telescopes, and the like. Car locks that work on 433 Mhz are not affected by PLT but I stop them dead for a range of about 20 miles, Wireles CH is even higher, probably on 1295Mh or similar, remote toy car, possibly but doubtful probably uses 27 Mhz, wireles doorbell see car lock, WX station see above.
One really needs to be concerned with shipping, communications for military, and the like. You will not be able to listen to things like luxembourg and will be left with DAB (Daft Attempt at Broadcasting).
I used to teach radio, electronics, electrical and the like, if this continues then interference may also be experienced in industry and hospital equipment, eg HF welders, spark eroders and the like.
The needs of the many outweigh the needs of the few (or the one.)
The needs of the few (or the one) outweigh the DESIRES of the many.
You don’t deny basic rights to the few (or the one) to enable the luxuries of the many. At least, you don’t in a civilised society…
I said something about a conscientous ofcom before*. Now, a minister for business apparently needs no conscience and can go right ahead promoting business (plt kit sales) over beardy hams (who obviously contribute nothing whatsoever to the economy**), but I do find the lack of argument, be it original, after making sense, or even vaguely related to the topic at hand, disturbing.
I probably shouldn't, as it appears to be /de rigeur/. Doesn't make me like it, though.
** Because, you know, they make things actually work and help out in emergencies and Know Stuff and if you talk to them, well, maybe you'll get cooties too!
DSL uses long and medium wave frequencies down your phone line
VDSL extends this into the short wave bands.
Phone lines are relatively controlled environments. They weren't designed for these frequencies but work remarkably well considering.
PLT uses long and medium wave frequencies down your mains wiring; modern PLT extends this into the short waves and far beyond.
Mains wiring is an uncontrolled environment, not designed for these frequencies, and is almost inevitably going to radiate like crazy, regardless of the design of the PLT equipment (completely_hatstand may be a ham but he appears completely_clueless wrt RF electronics and RF propagation).
PLT can't be done cleanly within the CE rules, end of story.
OK, right... So if I only kill a few people compared to the population at large, the problem is confined, and hence can be ignored?
BTW. I am not comparing use of PLT with murder; although some might; I am simply asking if laws can be ignored depending on how many people are inconvienienced.
"Mains wiring is an uncontrolled environment, not designed for these frequencies,"
In general - yes - but it can become much more controlled. That much is under the control of the builder or the subsequent owners, although the latter would probably involve more work than putting the network cabling in.
" and is almost inevitably going to radiate like crazy, "
It will do - yes. It may also do so in a manner that causes interference. It may also do so in a manner that causes interference at the frequencies of interest.
There's a difference in our statements however.
"regardless of the design of the PLT equipment "
The design of the PLT equipment won't interfere with the basic physics - but it can mitigate the effects seen by others outside of the structure containing the wiring. Methods for doing so have been discussed many times - some of them are implemented to a greater or lesser degree, e.g. static notches, and some have not (to any appreciable extent that i'm aware of) e.g. dynamic notching/channel activity detection.
As discussed countless times, there are a number of other points of consideration - the type and topology of the wiring, the structural and architectural details of the building (and it's surroundings) for example - that can have a significant effect on any interference generated.
"(completely_hatstand may be a ham but he appears completely_clueless wrt RF electronics and RF propagation)."
In what respect ?
"PLT can't be done cleanly within the CE rules, end of story."
Interesting statement of fact - care to back that up ?
I'm aware of the tests on there, and others from around the 'net, including some interesting Austrian reports (IIRC) into PLT interference. The latter includes Devolo devices, significantly better than the Comtrend rubbish dished out by BT but still fail. It's all very damning and very interesting. That said, it doesn't have anything to do with the statement
"PLT can't be done cleanly within the CE rules, end of story."
Change "can't" to "isn't" and i'd agree with you... as it is - no. Perhaps i've spent too much time picking the bits out of legal documents in the past, but if you're telling me it's impossible to shield RF transmissions then i'm going to object.
I'm not in favour of the lack of action on the devices - very, very far from it - but neither an I in favour of over generalisations, especially when there is no need.
...that the PLT problem comes in two parts, the PLT device itself and the mains wiring to which it is connected. Hence the manufacturers have the handy get out of saying "It would be fine if you didn't connect it to your house wiring, and when you do it isn't our fault". This is one reason why the wanted to change the LCL of the LCN used in testing from 6dB (realistic) to 24dB (unrealistic in the vast majority of installations). Fortunately this was prevented from being allowed.
It is of course possible to shield RF transmissions in wiring, but putting the necessary changes into houses is actually more difficult than simply installing cat5 or cat6 networking cables in the first place.
"if you're telling me it's impossible to shield RF transmissions then i'm going to object".
Perfectly correct Tim. Of course it is possible to shield RF transmissions. Thats what RF shielding is after all. And of course you can shield the RF transmissions from these devices by simply replacing all of your Mains wiring in your house with shielded mains cabling.
(P.S. See if you can spot the teeny-weeny issue in that last sentence which pretty much implies 'can't' is is a pretty good generalisation)
"P.S. See if you can spot the teeny-weeny issue in that last sentence which pretty much implies 'can't' is is a pretty good generalisation"
:) I pretty much agree too - shielded main cabling would be lovely of course, but more expensive than e.g. adding Cat 6, even if installed during the build (and why would you bother in that case ?).
However there are others things that can help - such as trunking, metallic (rather than just shiny) backed insulation, window glass, thick stone or brick walls - which may all be part of a existing building. That's not to say that they will stop everything, or indeed be used as excuse for flogging illegal kit in the first place - but i'm just trying to curb some of what (I believe) is over-stretching an argument that really doesn't need any more backing than the evidence it already has - and to indicate that not every use of every PLT device is inevitably going to create issues.
Yes - I totally agree that the manufacturers should be brought to book on this and we'll need to curb the use of anything similar, I think i'm more just tired of hearing potentially interesting discussions go off either extreme (yours wasn't, i'm just worn down).
Yes, yes Tim, it is possible to shield RF transmissions, everyone knows that. And yes, if you shield the RF transmissions, then the PLT will not send them down the wiring, and they will pass the conducted emissions test.
However if it stops sending the RF down the wiring I spot a flaw...
Another interesting point is that the CISPR regs are for "unintentional radiators". What happens when you build something with the intention of radiating RF down the mains wiring? Are they covered by the CISPR regs or not?
Yep, rewire the house with screened cables, all outlets shielded, Metalclad switches, special lamps, no flourescent power saving, they emit like fxxk.
Alternatively, build a faraday cage around the house with like an air lock but for radio waves. Oh yes all electricity substations will need to be also thus treated and filters installed in such a way as to block the stuff from getting into the HV.
MMmm yep can be made to comply, same as road safety, tanks fitted with moped engines to limit speed to 0.5 MPH.
The only way of making the average house wiring 'much more controlled' in this respect would be to use mains cables with rather better defined RF properties, and appliances that control the common-mode properties of the installation. As neither the specs for domestic mains infrastructure cabling nor the training courses for electrical fitters say anything about this, then 'much more controlled' is pie in the sky. Granted, PLT devices can be very useful, though my personal experience with them was less than satisfactory. But that's no reason to stamp all over existing users of the spectrum.
Thankfully PLT broadband from the local substation seems to have faded into obscurity.
"The only way of making the average house wiring 'much more controlled' in this respect would be to use mains cables with rather better defined RF properties, "
That would be the first thought... or shielded trunking (In the ideal world, trunking will be used everywhere anyway for a whole bunch of other reasons), perhaps chokes onto feeds not used on the "network".
"Granted, PLT devices can be very useful, though my personal experience with them was less than satisfactory. But that's no reason to stamp all over existing users of the spectrum."
Agreed - although in my experience they worked well where wireless could not cope (and re-cabling was not - unfortunately - an option.. at least not yet)
"Thankfully PLT broadband from the local substation seems to have faded into obscurity."
That is dead easy, you have only got to see the results of many PLT things, and the fact that the E companies want to raise the intereference levels.
Now let me see, if I cannot get that 30 ton load on my lorry, how about raising its GVW to 100 tons. That is roughly the equivalents.
Needless to say that you will therefore have no objection to me using my house wiring as my HF antenna, I guess you will not object to the weird hum coming through your Hi fi speakers, nor the TV picture that is "disturbed".
I shall only be using my power line to my shed the fact that it may go around the village as well is neither here nor there.
Nevermind that PLT has been flagged as disruptive and violating the don't bother the neighbours rule right from the start. So where, were I a minister, I'd certainly be tempted to handwave away problems because they're too small to bother with compared to the commercial interests of selling the kit, here it's a condemnation of the people in charge because they deliberately ignored the problem when the fix would still have been small, too.
But the real beef here is that, as they say, the buck stops at the minister's, so he really doesn't get to handwave away much of anything. If he ends up having to deal with trivialities, his organisation isn't doing what it should be doing. Which was obvious: ofcom is busily dodging their responsibilities and have been for a while. And that is very much his job to deal with and fix. Which he isn't doing.
Obvious conclusion is obvious.
It seems amateurs are the most vocal in their opposition to PLT/PLC/BPL because their vested interest in the subject is actually their hobby. As a rule, other experts have a professional vested interest that mutes them.
Almost all the pool of qualified RF (Radio Frequency) experts are NOW aligned to some professional organization that stops them speaking out (it was not always like this).
Likewise, the loss of tenure in universities, and the increase in commercial sponsorships and agreements etc. that universities have entered into, has muted their once-outspoken experts.
All up, the great unwashed internet masses and other communications services are more likely to suffer greater losses than the amateurs but they've no one to bat for their best interests.
I even had a bloke in communications in the military tell me that if he were to speak out or make waves over the PLT issue, his promotion and career would likely suffer.
Correct, the situation is outrageous.
Definitely not. Hence, it being a travesty that people in the UK can ignore the law against copying CDs they've legally purchased without consequences. It shouldn't matter that it inconveniences almost no-one and benefits many times more.
The BPI or someone, I dunno
"DSL uses long and medium wave frequencies down your phone line
PLT uses long and medium wave frequencies down your mains wiring; modern PLT extends this into the short waves and far beyond."
Does this imply that the #1 victim of power line networking may infact be the broadband it's supposed to be distributing? Given the whole 'up to' debate, it'd be pretty hard to quantify without a controled trial but were it proven i'd have thought it'd make the issue more interesting to people.
UKQRM has received reports of a decrease in sync and through-put speed for people who have both over-head telephone lines and over-head mains supplies; as you would find in a lot of villages. When Ofcom asked BT Vision to remove the devices, all of the villagers reported an increase in DSL speed.
An anonymous BT source also told us that VDSL is seriously affected by PLT installations from BT Vision. It seems one arm of BT doesn't know/care what another is trying to achieve!
Of course, we cannot provide you with quotable website references, but if you trawl through Google, there are quite a few forums where people are complaining of interference and fingering PLT as the culprit!
Some customers have been asked to throw them away. They are not even being issued in some areas and Vision boxes have to be connected to the HomeHub via Cat 5 cable. Not too bad if hub is in the same room as the TV, but can be a real pain if it's anywhere else.
Anon in case my boss sees this post (highly unlikely but you never know)
"Does this imply that the #1 victim of power line networking may infact be the broadband it's supposed to be distributing? "
You might possibly think that.
I couldn't possibly comment.
BT's DSL technical people at BT R+D Martlesham are well aware of the situation, but they are not allowed to comment either, because BT Retail are the major UK vendor of PLT kit.
Let's just say that it is clear that continued satisfactory DSL operation, in particular VDSL operation (VDSL = FTTC, BT Infinity, etc) largely relies on a clean RF environment between customer DSL equipment and provider DSL equipment.
PLT equipment and "clean RF environment" are opposites, incompatible, whatever.
It doesn't matter what kind of person makes the complaints, and whether or not they are deemed to be socially acceptable by the politicos, OFCOM not doing their job is still OFCOM not doing their job. They are there to stop people generating interference and the cheap and nasty versions of the PLT kits blatantly are.
HAM radio has a long history of being used in times of human and natural disaster and is an important last measure for keeping communication in times of need, as well as providing a hobby for many. At the moment use of PLT devices is relatively few but as these devices are becoming more popular it is not hard to see that it can make these radio bands unusable as the noise level accumulates. Its not that the HAM using neckbeards are the only people to be affected either, they are just the first people to notice while the problem is still small.
I don't do HAM radio but I do CB so we banter to each other often. A little bird told me recently that a few hundred watts of linear amplified SSB outside a house broadcasting the telltale PLT noise does wonders for reducing the issue ;)
....if it comes to it and an investigation is forced on them, Ofcom's field engineers will come and measure your transmitter's emissions and give it a clean bill of health, then pass the problem back to the owner of the PLT devices.
This is also true of other types of interference such as ADSL modems that are insufficiently RF immune.
One of the real problems is that few people will allow radio amateurs to add RF filtering to their equipment, even if it is a clip-on ferrite. They then complain, get Ofcom in to investigate and discover that they have no recourse because of their own intransigence.
Sadly in many cases the reporting of this sort of problem is done as a human interest story and is entirely uninterested in the technical reality because that doesn't make for good copy.
One of my neighbours asked me recently why one of his Freeview boxes has had its picture breaking up, he associated it with me because I just happened to put up a temporary antenna in my garden at about the same time that his problem began. I was able to show him the log that I still keep, and explained that his problems occur at times when my radios were switched off. I suggested that just maybe the Sandy Heath DSO and retunes might have a lot to do with it, he didn't seem to realise that he needed to retune his STBs.
There's a lot of ignorance about, and it's getting worse rather than better,
If my kit complies even IF I blank out a PLT or for that matter any other system, I MAY be asked to go QRT for a month, however they cannot blanket stop it. Why 'cos I ring a load of friends and they all set up in the local area and hey presto guess what. Now just ad a liitle high SWR (CB ers note) then PLT will love it. High SWR this is when there is a slight mismatch between the aerial and the transmitter, about 3" added to the top of a CB aerial will put the SWR out and may cause some problems, not only to PLT but also other things.
However If I happen to be trying out my military stuff then I can fiddle anywhere nobody can shut THAT down. A neighbour discovered that some years ago!!!
It's proposed that PLT/PLC/BPL be used for all sorts of internet traffic including VoIP which can be used by emergency services or calls to emergency services etc.
PLT not only causes interference but one can cause interference to it with incredible ease.
Remember, power lines have a humungous number of access points with which interference can be injected directly into the PLC network. Connect an interference generator to any power point and you'll bring the whole network down over a very large area.
1. THE POWER TO SUPPLY THE INTERFERENCE SOURCE/GENERATOR IS IMMEDIATELY TO HAND FROM THE *VERY SAME POWER POINT*. FURTHERMORE, THERE'S A FUCKING DAMN LOT OF IT TOO--2400 WATTS TO BE SPECIFIC.
2. IT IS EXTREMELY EASY TO BUILD CHEAP OSCILLATORS/NOISE SOURCES ETC. THAT TAKE THE POWER FROM THE MAINS SOCKET AND CONVERT IT INTO A HASH OF PULSATING COMB FILTER-LIKE RADIO FREQUENCY INTERFERENCE THAT'S SPECIFICALLY OPTIMISED TO JAMMING PLT SIGNALS THEN FEED IT BACK DOWN THE VERY POWER LINE FROM WHICH THE JAMMER DREW ITS POWER.
3. CONSIDER A NUMBER OF DEVICES NO BIGGER THAN SAY A POWER PLUG ITSELF--THEIR ELECTRONICS JAMMED INTO THE REAR OF THE SOCKET AND ARBITRARILY PLACED AROUND THE PLACE--IN OLD BUILDINGS OR LOCKED BEHIND DOORS ETC. WHICH ARE HARD TO GET AT TO DISCONNECT OR REMOVE. REMEMBER, POWER LINES ARE ALIVE AND WITHOUT PROPER ACCESS YOU'LL NEED AN ELECTRICIAN OR EMERGENCY CREWS TO DISCONNECT (CUT) THE LINES.
4. I SHOULD NOT NEED TO POINT OUT THE CONSEQUENCES IF PLC INTERFERENCE JAMMERS WERE TO BE DEPLOYED NEFARIOUSLY AROUND AIRPORTS, STADIUMS ETC. WHERE MANY PEOPLE GATHER.
Leaving aside the fact that PLT raises the electromagnetic radio spectrum's noise floor and damages communications, its susceptibility to interference and sabotage alone ought to be enough to kill its deployment stone dead.
The deployment of PLT/PLC/BPL technology--if one has the hide to call it a technology--is an utterly irresponsible act and it would have never seen the light of day except that in the 1980-90s, irresponsible governments downsized and outsourced their spectrum management authorities (along with their spectrum management engineers).
The only reason there's not total outrage or rioting in the streets over PLT is that it's not properly understood outside a small group of radio engineers etc. Tragically, commercial and vested interests NOW keep the few engineers who actually understand the implications of PLT deployment from speaking out.
Complain to your politicians before it's too late; advise them that if power line right-of-ways must be used for the internet, then instead of using PLT directly on the power cables, use the poles and towers to string up non-conductive (safe) glass fibre optic cables with its negligible susceptibility to interference and almost infinitely better bandwidth.
'Tis an infinitely better solution.
FYI: NATO is concerned that its military communications will suffer as a consequence of PLT/PLC/BPL:
Actual NATO report here:
I've been following this argument with (vague) interest for a few years. It's certainly a tricky one. On the one hand the law is most certainly on the side of the Hams. On the other side, Home networking kit is vastly more useful and will continue to be sold regardless. I was trying to think of a parallel and the only one I could come up with was cars.
When cars first appeared all road-laws were (obviously) in favour of pedestrians, horses, carriages and (to a lesser extent) bicycles. However, it quickly became obvious that cars were vastly more useful and were going to take over road use no matter what our law makers did. Therefore they did the sensible thing and changed the law in favour of car drivers. Now, pedestrians, cyclists and horse riders are 2nd-class citizens (at best) on our roads. There is no moral justification for this. They were there first and are more vulnerable. Theoretically they should be protected from the car. But it made economic sense and, in any case, the law was changed to reflect the emerging reality.
Of course, I am not suggesting PLT is as important as the car but it is quite clearly vastly more useful in terms of both public uptake and economic driver than using the spectrum for amateur radio hams. It is not morally right and hams can rightly feel aggrieved but we are (moving toward) a post-Christian society where economic reality sometimes comes ahead of moral "correctness".
(and please don't start with the "what about the military?" argument. If it was truly interfering with military use it would have been stopped in it's tracks)
I think you will find your analogy flawed: Pedestrians, cyclists and horse riders have the right of way on the public highway, not the motor vehicle! If a pedestrian steps out in front of your vehicle you are duty bound to stop, or you will be charged with 'driving without due care and attention' or possibly 'dangerous driving'.
The same applies to radio users. ITU radio regulations are internationally binding and PLT does not have the right to ignore them! EMC regulations are also an EU mandate transposed into UK law and PLT does not have the right to ignore that either!
Amateur radio isn't *just* about having a natter - although we do that too - if it was you'd have at least half a point.
It is, by definition, an experimental hobby - and fundamental to that experimentation is the ability to transmit and receive signal by radio, otherwise you're unable to do the very science you're licensed to do... which may involve propagation studies, may involve circuit design, aerial design, or involve developing new digital modes and the supporting software to get a signal through under extreme circumstances - as well as training and practice for disaster-preparedness.
The fact many of us are able to continue working indefinitely in the absence of mains power or indeed any other infrastructure makes us extremely useful in disaster situations - we do form part of the 'disaster plan' of most local authorities in the UK and beyond as we'll still be working when everything else has stopped.
God forbid we have the sort of disaster here they had recently in Japan, or Haiti... but if that happens, us 'beardies' will be helping keep you alive when nobody else outside the military can communicate further than they can shout.
People not involved in radiocommunications often do not realise that just about all wireless/radio communications struggle with various forms of electrical noise. Wireless signals compete with every conceivable form of noise generated both by nature itself, lightening, solar disturbances, aurora borealis etc. as well as human-made electrical disturbances such as from motors, electrical switches, RF heating and other competing transmitting devices.
In addition to all that interference, radio circuits (paths) are incredibly lossy. The loss of signal from the transmitter to receiver can be (and usually is) enormous. Path loss figures of 120-140dB or more are not uncommon. Because of these huge losses, radio engineers are always concerned with how much margin there is between the received signal and the noise--so much so that the signal-to-noise ratio (expressed in dBs) for a given circuit bandwidth is essentially the most significant engineering parameter in wireless communications.
To illustrate the point, a powerful television transmitter can have a power output of between 100kW and 1MW yet the received signal at the typical TV set is so infinitesimally small that if amplified a thousandfold would probably not light the tiniest of pea lamps.
Keeping radiocommunications working efficiently is a remarkably complex and sophisticated engineering operation. Over the last 100 or so years since Marconi spanned the Atlantic, many complex rules have been formulated under the auspices of ITU (International Telecommunications Union) with the express purpose of optimizing and finely balancing competing demands for radio spectrum from various radio services. Interference and noise being one of the predominant concerns for the international regulation.
Into this mix comes PLT/PLC/BPL bulldozer. This broad-spectrum signal--which is better suited to modem-to-modem communications--pays no credence to the delicately balanced mix of incredibly minute radio signals contained within the specialized, especially-allotted radio frequency bands designed specifically to minimise interference. PLT just blankets the lot. To make matters worse, the PLT signal (which ought to be contained within a shielded cable to stop it radiating), is in fact connected to the world's biggest 'antenna'--the world's power grid.
Whilst regulators and PLT companies pay lip service to minimizing interference by tailoring the spectrum to work around some of the more susceptible wireless circuits, it is essentially tokenism. Whilst some radiocommunication circuits initially appear better off--usually only in specific areas--PLT is radiating everywhere--across cities, up into the ionosphere etc. In essence, PLT can be likened to a diffuse fog that's enveloped the radio spectrum across the whole planet, thus PLT is effectively increasing the noise floor with which existing services have to compete. It's interference pollution of the very worst kind. It's environmental damage to the radio spectrum on a level akin to or worse than the Alaskan Exxon Valdez oil spill disaster; yet except for small numbers of radio amateurs, few others complain.
Why this unmitigated disaster ever happened is still open to debate and a full analysis (but I briefly touched on a couple of issues earlier).
PLT is so fundamentally flawed that it's only seen the light of day because of carpetbaggers and charlatans, the incompetence of regulators and blind eyes of standards bodies.
There are much better engineering solutions which keep the spectrum 'green' and pollution free.
"If it was truly interfering with military use it would have been stopped in it's tracks"
Once this may have been so, but it's not the case anymore. Shame I've not the time or space to debunk this statement.
Suggest you do some research, begin with the NATO doc ($$TR-IST-050-ALL.pdf)
Even if there was some official conclusion that ham radio was unimportant, and it could be shown that nothing else was affected, and it was concluded that PLT equipment was important enough to deserve lax regulation, the powers that be should still at least be honest enough to come out and say that, and change the regulations rather than just carrying on as if nothing is happening.
By basically ignoring what's happening, they're effectively admitting that they *should* be doing something, but that they just don't find it convenient to do their jobs.
Whether that's down to simple idleness, excessive connections with lucrative industry, or anything else on the part of Ofcom +/or ministers, it's hardly a good example to set - '"There *are* rules, but we'll pretend they don't exist when it suits us".
Whatever the actual reasons for inaction may be, the *impression* they give is of incompetence or corruption.
And then politicians moan about how people are cynical about politics and politicians.
>>"It is not morally right and hams can rightly feel aggrieved but we are (moving toward) a post-Christian society where economic reality sometimes comes ahead of moral "correctness"."
And when British society was supposedly Christian, you think that morality always came ahead of economics?
It seems that you have no grasp of the subject, the problem is that there is no real way to keep the RF inside the cable. Consequently it will escape and affect other things. You will obviously understand that most aircraft will probably have to be grounded. During the 1970's a CB with only about 4 watts did that as his frequency multiplier due to poor SWR blocked both the landing frequency from then West Drayton and also all the emergency vehicles at London Airport.
You can imagine it :- Tango Charlie 13 take bzzzztatatatssszta roger. Useful!
As a former Elect tech for the USAF and radio op BFG and instructor radio for ATC and running my own business as an electrical contractor, let alone being a radio amateur I have a wee understanding of the rammifications. It will only be a brain dead who sanctions this again. Anyway, I thought that this was thrown out several years ago after tests revealed economically flawed problems.
Guess I will have to connect an RF transformer to the mains and crash out a CQ EDF.
A lot (most, if not all) of compact florescent lighting splatters right across the spectrum.
It could be that OfHalfWits decided that PLT was emitting less than CFL so it's ok, but in 5-6 years time CFL will mostly be dead (LED prices are in freefall) and PLT will still be around. :(
Some chipsets for PLT clearly use higher frequencies for speed gain whilst others do not. There are 2 main chipsets on the market that everyone is using to beat on PLT in general. The original kit supplied by the largest UK telecoms company for one, who are now using something different which should not cause the same issue.
"All chipset, be they DS2 or the new VHF-based Gigle,"
You're missing Intellon - used by many/most of the HomePlug stuff. The notching is also configurable by firmware.
" cause un-acceptable radio interference when used over un-balanced mains wiring."
'cause radio interference' - the degree of acceptability is dependent on many more factors than the chipset and vanilla firmware in a PLT device.
PS. There's a hell of a lot of ACs around at the moment - any particular reason ?
"The original kit supplied by the largest UK telecoms company for one, who are now using something different which should not cause the same issue."
Are you really saying that because the largest UK telecoms company is a supplier that it has no vested interest?
Doesn't everybody make rewiring the house with CAT5e/6 a priority as soon as they move in?
I, for one, welcome the opportunity to drill holes through walls, and drag cables through buried hosepipes, and crawl through insulation-filled dusty loft spaces, and risk life and limb on dodgy rafters in the name of establishing a reliable network connection between one side of the house and the other.
I find the experience of appearing on Google's wifi database disturbing. And broadcasting my network traffic several blocks via powerlines is unappealing too. (Granted it's encrypted, but how long will the algorithm remain publicly unbroken?)
Shielded cabling for me, thank you very much. I like my signals crisp and guarded.
"can't be done cleanly" is shorthand for will not be practical technically or economically in an environment where legacy-designed mains cabling is in use, ie 99.99%+ of all premises in existence.
Legally speaking, vendors should be able to provide demonstrations that their product will meet CE requirements in a realistic environment. It's not supposed to be down to objectors to show where the product fails the requirements.
Anyway, you say it can in principle be done. I say it's unrealistic,
I say if recabling is required to ensure CE compliance of PLT kit, why not put in proper LAN cables at the same time so that there is zero risk of PLT-related emissions? (Because the PLT business model disappears, that's why, obviously)
Happier with the new form of words now Tim? The net effect is the same, PLT can't be done cleanly in the real world in any practical sense.
As a radio ham I keep wondering what would happen if I lodged a complaint with OFCOM/BBC about PLT causing me as a ham interference......
If it was the other way round and I as a ham was causing interference it would potentially be investigated and I could be asked to stop for a period...
Do we think they will ask said PLT user to unplug for a period...
Or is it same old one rule for one etc....
...272 times. And with resolutions in 230 odd of those cases.
In most cases BT Vision installations are the culprit, and BT know that the Comtrends are problematic so they come round and remove them and hardwire with ethernet cable instead. However, Ofcom say they don't have the powers to compel this so if the BT Vision customer refuses the cabled approach then there is currently a stand-off.
'"can't be done cleanly" is shorthand for will not be practical technically or economically'
If i'd known that convention, i'd not have said a word.
"Legally speaking, vendors should be able to provide demonstrations that their product will meet CE requirements in a realistic environment. It's not supposed to be down to objectors to show where the product fails the requirements."
"Anyway, you say it can in principle be done. I say it's unrealistic,"
I also agree with both - there is no confict here.
"I say if recabling is required to ensure CE compliance of PLT kit, why not put in proper LAN cables at the same time so that there is zero risk of PLT-related emissions? (Because the PLT business model disappears, that's why, obviously)"
Yep - i've been saying for months.
"Happier with the new form of words now Tim? "
Yep - that was my whole objection. I just hate absolutism.
"The net effect is the same, PLT can't be done cleanly in the real world in any practical sense."
I agree with that too.
I wrote: you say it can in principle be done. I say it's unrealistic,
Tim wrote: I also agree with both - there is no confict here.
There is indeed no conflict, that's why I chose those words, but had neither time nor space to explain explicitly.
Anyway, we're agreed, as are most (all?) logical-thinking independent-minded people on this subject, as they have been since (e.g.) the RadioCommunication Agency's DSL/PLT/RF Technical Working Group(s) back in 2001.
But WTF can folk actually *do* about this? Please don't suggest "write to your MP", mine's a useless timewaster, and so are most of them.
off topic ps:
El Reg: Captain Cyborg is back! The recently invisible Kevin Warwick is on BBC Today as I type this.
A selection of interesting "articles".
The last is interesting.
That is indeed well worth reading.
Didn't the RSGB used to have spectrum defence fund or something? e.g.
Can any kind reader confirm whether it's still active?
I particularly liked the non technical (not to mention nonsensical) nature of "Ofcom has said that failure to meet a standard does not mean a product is non-compliant. "
When I were a lad, things that met relevant standards were known as "compliant", and things that didn't, weren't.
Obviously I'm behind the times. But in an era when the IEE Newsletter could be mistaken for T3, maybe that's my problem. Does the IET even have a stated corporate position on the PLT subject, or are their folks at HQ just waiting for their next award for magazine layout+design?
Whose name is on Comtrend's published Declaration of Conformity? If these named individuals, rather than their corporate employers, had to be individually accountable for their actions (y'know, "lie to us and we lock you up", kind of thing) would these things work out any different?
Thank you, have a good weekend.
Many of us "amateurs" are also proffesionals. If we were for example lorry drivers, does making us being on motorcycles make us amateur drivers, does driving an ambulance for a living but driving a car at weekend make you a weekend driver.. To feel enthusiastic about ones chosen proffesion enough to also dabble in its various forms does not make us amateurs.
Possibly in these days the name is a misnomer, however, seeing as many of us also work within allied fields, or continue after retiring should really give us a better chance to convey to others the various situations.
Hence many of us may feel inclined to coment to the adverse anonymously to preclude potential situations as could develop.
If the so called investors were REALLY serious then they would look at Wimax, total removal of all phone lines, each person with a FREE phone in his location, really fast internet access and the like. CHEAPLY, say £20,000 1 time payout and virtually no running costs apart from electricity.
Therefore it is in the interest of idiots like the MP who uttered the daft statement and other do gooders to take heed. There are sufficient lines (intended pun) of routing for the internet and telephone without recourse to dubious practices. The removal of all the copper wire precluding theft for scrap and replacing with Fibre will allow speeds up to silly speeds, let alone the reduction of exchanges and the like and interference from outside sources will be of major importance, so to spend vaste sums of money on aforesaid systems instead of the fibre is a course that will only be beaten for stupidity by the DAB system that has more holes than a collander and is now not being considered for the EU.
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