62 posts • joined Thursday 30th December 2010 16:42 GMT
Many of the reasons for only moving to Windows 7 are coming from the big software houses. I have worked with architect and theatre design companies who have only recently started to kill off the last of their XP machines. They are only moving to 7 as software houses, like AutoDesk, have said they have no immediate plans to support 8 (although that may have changed...), and many of these companies have a large install-base of CAD-type applications, so they want compatibility and support. Having now standardised on one version, and remembering the hassle of an XP/7 mix, they are not interested in a 7/8 mix and all the problems with a touchy interface.
Re: Digital One
Yes, they will be scrap, unless 'Pure' (and other manufacturers of other brands) offer replacement boards for the insides of the radios. If the government does move to DAB+, all of the older DAB-only radios will become WEEE junk as many have their functions embedded in silicon. A chip change will be required for them to work with DAB+; and that's not in the manufacturer's interest when they can force you to spend another ~£100 on the "latest and greatest". That will put people off, with many just giving up on broadcast radio!
Perhaps the drop in listener numbers is down to the farce that is Digital One. Dropping my favourite radio stations, Planet Rock and Absolute Radio 80s, to MONO and a stupidly low bit-rate has resulted in me ripping my digital radio out of my Hi-Fi stack. I have no interest in listening to the BBC, so for me, DAB is dead. And that is quite annoying and costly. I was a fan - although not of the bubbling or crap MP2 codec. I have a self-fitted DAB unit in the car that will be removed soon, plus a number of "collectors edition" 'Marshall - Planet Rock' branded DAB radios that are technically scrap (they do not do FM). I am forced to stream Planet Rock and Absolute Radio 80s over the Internet, which only works for the Hi-Fi system. It's useless in the bedroom, or when one is out mobile.
Dates mixed up!
Quite! I worked in a small company from 1990 to 1995 and we were producing ETACS and AMPS test kit for the two international standards of the time. GSM had only just started to appear in 1995.
How about a regulator who does!
How about paying for a regulator who actually protects the radio spectrum and does its Market Surveillance job by removing non-EMC-compliant junk from the market-place before an un-suspecting public waste their hard earned money on it?! The current crop of self-serving civil servants that infest Riverside Towers are clearly not up to the job, so sack the lot of them, re-light the bonfire and start afresh with skilled engineers, technicians, and lawyers who are not frightened of the EU!
Check the transmitter footprints!
"The frequencies used to transmit TV in Slough are different from those used at Crystal Palace, to avoid interference, so the Slough frequencies are empty in Islington where they can be used for short-range wireless or point-to-point links."
WRONG! Check what you are going to write about Bill, before you make yourself look like an ejit! Slough is covered by Crystal Palace for TV, as it most of the surrounding area. The only transmitter in Slough is for analogue radio! If you want to use white-space TV frequencies in London, you will have to use those of the surrounding transmitters, like Sandy Heath.
Was a fan of DAB...
I have spent quite a bit of money over the past few years on DAB radios and they have all recently been rendered useless - unless I want to listen to the BBC, which I don't! The fiasco that is Digital One should not have been allowed to happen, yet Ofcom seem complicit in helping/allowing the farce - but then Ofcom have been doing quite a good job of ruining the radio spectrum for years. I am now forced to stream Planet Rock/Absolute Radio 80s over the Internet in order to listen with any "quality". 80kbps and Mono is not progress. It's no better than a 6kHz-wide AM transmission! In the car, my retro-fit DAB radio is now sitting there dead - and may well end up removed. When I am driving locally, I might listen to BigglesFM, as it is somewhat more tolerable than the blandness of Heart/BBC. For all other trips, the iPod comes into its own!
No such thing as degrees Kelvin.
Kelvin is an absolute temperature measurement, not a relative one; ergo, no need for the degrees symbol!
Re: For those of us less technical.....
Opt for an LCD TV (not plasma!) with a DVB-T2 receiver and native 1920x1080 resolution, then you can receive High Definition - assuming your local transmitter is supporting it?!
There are a couple of ways you can experience interference, other than the usual blocking and pausing (my aerial is a mere 2.5km from Sandy Heath, which transmits 220kW, yet my TV and DVR still experience drop-outs!). If a 4G operator enables a tower (or builds a tower) that your aerial can see, the powerful signal (I say powerful - it's all relative to the power of your local TV transmitter(s)) may blind your receiver to the TV transmitter. Yagi aerials (used for TV) typically have a +/- 15 degree acceptance angle, so even if it is pointed dead-on to the TV transmitter, a nearby tower within the 'acceptance angle' could still cause a problem. Think of trying to look at a torch in the distance whilst some yob shines a laser in your eyes.
The other problem could come from a nearby 4G tower in your local area. As we are talking about milli-metric wavelengths (a quarter-wave at 800MHz is ~93mm), there is always the possibility of pick-up on the co-axial cable, or the aerial itself; even if it's pointing in the other direction.
Both of the problems above can be exacerbated by a wide-band aerial (possibly fitted to cover both analogue and digital transmissions) and/or an amplifier-splitter. Aerial amplifiers are often wide-band, covering Band II VHF (87.5 - 108.5MHz), Band III DAB (220 - 240MHz), and both Band IV and Band V TV (400 - 800MHz). A strong 4G signal could overload the amplifier and cause it to parasitically oscillate (poorly designed models can do that all of their own accord!). Result: no signal!
We have no real way of knowing if the 4G roll-out will affect few, or many. As Ofcom have no technical expertise, and have farmed out domestic radio and TV interference problems to the BBC, I am sure people are going to be left scratching their heads staring at a black mirror.
I hope you found this reasoned guidance?
CBer and non-bearded Radio Amateur.
I can recommend Eclipse Internet.
I have been with Eclipse Internet since my local exchange had its ADSL switched on (over 10 years ago) and I've never looked back. They were a leap ahead of the NTHell service I had at the time!
Granted, they only re-sell BT's wholesale ADSL/VDSL products, and they have yet to catch up with the latest 80/20Mbps VDSL offerings, but, you can have up to two fixed-IP addresses for free; free reverse DNS for your mail server(s); use your own routers; and their call-centre is in Exeter, although sadly it is not open at weekends. Their support staff have always been very helpful; and a BT Openreach engineer commented to me on how detailed their fault reports were - more detailed than he received from BT!
Re: What's the point of either standard, given ubiquitous WLAN?
You are correct that PLT splatters the mains with multiple OFDM carriers. When neighbouring devices are on the same mains-interconnects (i.e., the same phase-neutral between houses) it is the case of he-who-shouts-loudest. Many PLT devices simply ramp-up their transmit power to try and overcome other noise sources on the mains. I have read of cases where a noisy switched-mode power-supply, which also did not conform to the requisite EMC standards (filter components omitted by the manufacturer), rendered a PLT installation useless due to the noise levels on the mains!
Most of the "set-top-boxes" requiring PLT are missing a trick w.r.t. Wi-Fi. Is it really that hard to fit dual-band Wi-Fi and start using 5.8GHz? They could even include a neat little external aerial to tuck away behind the TV. Hardly rocket science!
Hardly "6 billion" making use of ham radio, TV's higher up the dial anyway ... are there really more radio hams than people wanting home networks? I doubt it. Just have an equipment buyback, trade all the ham gear in for a VoIP handset, problem solved ;-)
Billions of people in China, Russia, Africa, North and South America, and throughout Indo-Asia rely on shortwave radio to keep in touch. If you wish to deny them, please feel free to explain it to them. I am sure you will go down a storm!
Let's see your VoIP handset work in the middle of a field/up a mountain!?
The needs of the many............
The needs of ~6 billion people on the planet, who use radio to communicate, watch TV, listen to music, etc., outweighs the needs of a selfish minority who are too lazy to run a bit of Cat6!
Re: I've often wondered about the security of powerline devices.
The most effective thing to do is to insert an isolating transformer between your installation and the public grid. Another method is to wrap the incomer around a metal toroid which will block the higher frequency components.
You do realise that a common-mode choke rated at 100A would be the size of a fridge and require a sturdy concrete base? That will be the only way to stop conducted emissions from PLT in other houses!
Non-obviously it is possible to couple from one set of cables to another, so your neighbour could put a transmitter on their side of the wall and turn the power up...
You and your neighbour are likely to be connected to the same phase and neutral from the 3-phase in the street. It is only a matter of time before someone engages in a little neighbourly social-engineering and connects their PLT devices to their neighbour's. People do not understand how to secure their Wi-Fi or their routers, so PLT will be an easy target, AES256, or not!
Re: Crud generators.
Which "hobby" is more deserving?
The one that requires considerable technical study and examinations in order to obtain a licence from the government; plus the ability to set-up emergency communication-links during local/national/international disasters. My radios and aerials can cover anything from 20km around my home, to 2000km away in another country. Can your precious PLT answer the call for help?
FprEN50561-1:2012 is not a standard!
FprEN50561-1:2012 is not a standard, it is still a draft that fails to meet the 'essential requirements' of the EMC Directive. It will not be adopted by the European Commission until it does meet the requirements. In the meantime, EN55022 Part B (residential usage) is still the applicable testing-standard for PLT. Of course, PLT manufacturers will continue to lie on their 'Declarations of Conformity' and claim compliance to incorrect testing-standards (EN55022 Part A - Industrial use only, not for domestic usage!) and non-existent "standards".
I think AmiPro from Lotus was the nuts! I was an avid power-user of AmiPro through the 90s. It blew the arse off Word, Works and Wordperfect, and it was such a shame when IBM ruined it. I could write long, complex technical manuals in AmiPro in minutes. Styles control, and the ability to switch styles with the press of a Function key is sadly lacking in today's wordy-processors. They are all rather clunky and awkward to use by comparison.
Post Code or IP trace?
I so want this technology to work and become a sensible alternative to that crappy PLT! However, I can see problems that need to be overcome.
I assume you will be required to enter your post code into the device before it checks said databases? If it's going to work on tracing the IP address, I am in a variety of places in the country - according to Google. So if the IP trace suggests I am in Newbury and sets the device accordingly, it's going to cause a problem for me and my neighbours, who all receive from Sandy Heath.
And we already have the problems of LTE being pushed into the TV bands and the possibility of interference. I wonder how much testing has been carried out to ensure one of these devices parked near your TV will not wipe it out? I live 4.6km from Sandy Heath transmitter, have clear line-of-sight to the mast, and I still suffer blocking and drop-outs on my TV. Even if power is limited to 100mW, the near-field is still going to present a much stronger signal within the house than the local TV transmitters.
The Morality Police
Who is actually demanding this? Is it the same parents who allow their children to play age-restricted violent video games and watch age-restricted violent films, yet baulk at the idea of them watching pr0n?
I challenged my friend about him allowing his 12-year-old son to play 18+ violent games. I suggested he might as well let him watch pr0n as well. "Ahh, that's different!" came the reply.
So can someone please answer me this: Since when has violence in games/TV/film been more acceptable to society than watching two people engaging in sex? After all, sex is how we all got here! All violence leads to is death.
Not quite a done-deal!
The proposed "standard" (read: pack of lies) prEN5056-1:2012 has only been accepted by CENELEC, which was not a surprise considering the Working Group is made up of pro-PLT companies wanting to further their crap technology. This whole shambles taints anything CENELEC is now involved in!
prEN50561-1:2012 has to be accepted by the European Commission before it can be legally used; not that PLT companies stuck to the rules in the past! Many aspects of prEN50561-1:2012 contravene the 'Essential Requirements' of the Electromagnetic Compatibility Directive 2004/108/EC; something which the EC's own EMC adviser stated, before being completely ignored by CENELEC. The two cannot co-exist, so one of them will have to go. If it is the EMC Directive, you can kiss goodbye to any electronic device ever working correctly again!
prEN50561-1:2012 contains a number of mitigation "technologies", such as 'dynamic notching' and 'dynamic power control' - a tacit admission that PLT creates interference! Neither of these "technologies" exist, other than being mentioned in the "standard". Dynamic notching required the PLT device(s) to listen for other users of the radio spectrum. If all they can hear is other PLT units in the area, they will simply add to the interference. Can you see the irony and madness of that?!
Will it end with prEN5056-1:2012? If this nonsense is not kicked into touch, every manufacturer or trade body that does not want to conform to existing standards will use PLT as an excuse and a reason to demand their own "applicable standard". Everything the EMC Directive has sought to protect will be lost!
Standardise the voltage as well!
All laptops/routers/display screens with an external PSU should really run from 13.8Vdc. Why?
(i) Manufacturers are missing a trick with people who live on boats, go on boating/caravan holidays, or the road warriors/radio users on field-days who need to keep their laptops running. The ability to plug in to a vehicle/boat's 12V power system has long been overlooked. I appreciate this will mean many devices will have to curb their power-hungry nature, but this may force manufacturers to use better techniques and not scrimp on cheap and nasty electronics!
(ii) A very simple and efficient UPS can be created with a 13.8Vdc power supply and a standard lead-acid battery. There will be no conversion losses switching the voltage back up to 240Vac.
(iii) You could replace a number of wall-warts with one phat SMPS and a distribution system; like the 10 or 20A devices we use for CB/Amateur Radio.
Quite simple, when you think about it!
Re: If a HAM radio enthusiast
A harmonic (or multiples of) from an interfering device can just as easily be picked up on the co-axial braid and fed to your satellite box causing degradation/disruption of signal, interference to internal timing oscillators, or interference to digital processors. You are no more immune to RFI by using a satellite receiver than someone using DTT Freeview or digital cable!
Case in point: I had fitted some "buck-driven" LEDs to my vehicle. When the side-lights were switched on, my C.B. radio went nuts. The switcher circuit was supposed to operate around 5kHz, but the harmonics it created were spread right up to 27MHz, and possibly beyond.
"Mr Ronald L. Storrs (SE):
TELIA, the Swedish telecom operator and leading Nordic communication company, PLC service provider."
So no vested interest in PLT then?
And at least 22 - including the Project Leader - represent the PLT lobby (ILEVO, DS2, SONY, CTI, INTEL, SIEMENS PTD, TCA, ENF, EDF, UNIVERSITY DUISBURG-ESSEN, MAINNET, PPC, FRANCE TELECOM, BRITISH TELECOM, ENEL, INTELLON, ENA, TELIA)
Not trying to stack the deck in your favour at all!
Re: "PLT manufacturers are lying on their EMC Declarations of Comformity"
There is a requirement under EU law that members states employ a Market Surveillance authority to oversee breaches of regulation, such as false CE declarations, contravention of the EMC directive, et al. Here in the UK, that responsibility falls to BIS, who in turn farm it out to Ofcom. Neither are interested in performing their statutory duty, so when Trading Standards seek their help to deal with manufacturers who are flouting the EMC regulations, Ofcom pat them on the head, tell them it's all OK, and TS have to let the case go. This is primarily how PLT has made such a large impact on the market, along with being handed out like sweets with BT Vision. Had the laws been adhered to, PLT would not be on the market!
PLT must be tested against EN55022 as it is Information Terminal Equipment, or ITE. The EU have stated that EN55022 is the correct standard to test against, so PLT manufacturers are lying on their EMC Declarations of Comformity and stating they pass EN55022 part A - which is for Industrial use only - will cause radio frequency interference. For domestic use, they should be tested against part B. This calls the whole DoC and CE system into question and renders it completely worthless!
Irrespective of EN55022, PLT must also pass the 'essential requirements' of the EU's EMC Directive 2004/108/EC; namely that it does not cause undue interference and stop a radio system from working as intended. The 'essential requirements' apply to all devices places on the market and PLT is no exception to that rule! prEN50561-1 cannot overrule the 'essential requirements', which it is seeking to do!
It should be noted that those driving prEN50561-1 through CENELEC are primarily from the PLT manufacturers. They are attempting to stack the deck in their favour and if prEN50561-1 becomes a standard, everything EN55022 stands to protect will be destroyed. Once that happens, other manufacturers will want to relax EMC rules for their products, and before long, all of you bleating on about Hams being a bunch of selfish <insert expletive here> will find your precious Internet connection dead thanks to interference from other electronic devices! Many of the proposed solutions for prEN50561 (smart notching, dynamic power control) either do not exist or are patent encumbered, so how can a standard for testing/compliance be produced when much of it is pie-in-the-sky?
What will it mean for you? Whilst the internationally agreed amateur radio bands and the CEPT Ciitizens' Band allocation will be protected by notches (a tacit admission that PLT creates radio interference), the rest of the HF band will be wiped, so if you like using ADSL/VDSL, listening to shortwave radio, or you need to communicate with aircraft over the Atlantic, or ships out at sea, you can forget it!
Re: Not just PLTs
CFLs and strip lights should not be confused. CFLs use a handful of electronic components to "strike" the tube as they lack the same choke and starter found in strip-lights. When those electronics are of cheap and nasty Chinese manufacture, or they simply start to fail at the end of their life, they can create a wide-band spark-gap transmitter. This noise is fed back into the mains wiring where it finds a nice multi-path and multi-wavelength aerial. The user may not notice this if they do not engage in Medium Wave or Short Wave radio listening.
Alan Brown is correct, it is not just PLT, but CFLs, Plasma televisions, Switch Mode Power Supplies, LED buck-drivers, Thermostats, PWM controlled gas boilers, PV inverters and more which are all failing the Essential Requirements of the EU's EMC Directive (2004/108/EC) - they being to not cause unacceptable interference to radio systems that results in those radio systems being unusable.
Re: Watch out for cheap LED lights
Ironic is it not, that PLT can only operate correctly if everything else on the mains actually meets their EMC regulations and do not load the mains with noise!
Re: Radio Hams are full of crap
Many of the new devices are listing compliance with EN55022 part A - which is for industrial use only (creates RF interference). They should be tested to part B (domestic use), but they would fail the conducted emissions tests, so they are lying on their Declaration of Conformity! Therefore, their CE mark is invalid as the product has not been correctly tested. Market Surveillance organisations in the EU are supposed to deal with breaches of this kind; but it's left to BIS/Ofcom in the UK, and they are completely useless!
Re: Apples and Oranges
Wrong on so many levels!
The meter in your property does not stop conducted emissions from mains-powered devices in your property from radiating back along the wires to other houses in your street, or vice-versa. If those mains cables are overhead, as in many villages, they will become aerials and radiate. In order to establish a clean mains signal, you would need a 100A-rated common-mode choke; and that would be the size of a fridge!
PLT's Orthogonal Frequency Division Multiplexing signal injected onto mains wiring is at such a high level that it radiates along all of the phases, neutrals and earths in your property (with the earths connecting to the neutrals at the incoming supply as part of the PME installation). This signal is also conducted to neighbouring properties who are on the same 415V phase, and all properties on the same transformer thanks to the common neutrals. This signal is further radiated along the earth wires of the properties and up each lamp-post in the area. This is physics and you cannot change that!
You are right, in that PLT is not a particularly large concern to Radio Amateurs if notched correctly; however, CB users are quite pissed as their allocated bands are wiped out. It should be noted that each part of the planet is divided into three ITU zones, and each zone has slightly different operating frequencies allocated for amateur radio. So a device with notches for ITU zone 3 is not necessarily any good in zone 2. Of course, with non-linear devices, such as switched-mode power-supplies on the main wiring, the notches become useless and fill up with intermodulation products.
As others have mentioned, with these devices failing to comply with the EMC Directive's "essential requirements", they fall over and lock up in the presence of powerful radio fields. A fully licensed radio amateur can legally transmit up to 400W - maybe more in the future if the UK's rules are harmonised. If your precious PLT devices fall over due to a lack of RF immunity, there is sod-all you can do about it, you have no grounds for complaint and no-one to complain to!!
Re: You forgot breeding
A work colleague used to suggest I had a large carbon footprint because I drove a sports car. I suggested his was 20 times larger than mine as I did not have a wife or two kids to feed, cloth and heat. He didn't like that!
Last time I checked, my estate is littered with cabling cabinets from the NTHell days (now Virgin Media) and the scars in the pavements are still clear to see in many places. VM like to claim they are offering fibre-optic Internet access, but we all know it's over copper co-ax. Like BT, they will have to re-do their cabinets if they want to offer FTTP.
Openreach (well, their contractors) have been installing their FTTC boxes all over my town and my ISP tells me it's available (just waiting on them to sort their daft business pricing). It will make a change from being stuck on 8192/448 for the past 8 years, but I would prefer someone to blow fibre up to my house!
Any lawyers present?
Is it legal for the council to ban photography in a school? Is that actually written down in Scottish statute, or is this another case of civil servants overstepping their bounds?
The heart of the problem...
...is a bunch of un-elected, un-accountable civil servants who, with some (mis)direction from BIS, have chosen which laws they will enforce and which laws they will ignore. Ofcom's model of operation has been to generate cash for the exchequer and sod-all who get in its way!
Let us take the case of Electro Magnetic Compatibility. It is law, written into UK statute from EU Directive 2004/108/EC. The EMC regs were created in a time (1980s) when all sorts of electronic devices were bursting on to the market - and they were interfering with each other. EMC regulations set limits for generation of interference (some is allowed) and immunity from interference (your computer doesn't crash when you turn on a light). These are neatly rounded off with the essential requirements that devices do not wipe out important services, such as radio.
Add to the above, CE testing and certification. If a product is to be placed on the EU market, it must pass standardised tests to ensure CE compliance; and some of these include EMC tests for electronic devices. Member states are required to provide a Market Surveillance facility where products are monitored, and where necessary, tested for compliance. In the UK, that responsibility is handed down from BIS to Ofcom. So if you report a faulty electronic device to Trading Standards, they are supposed to be able to call on Ofcom's "expertise" to determine if the device meets the essential requirements of the EMC directive.
So why is the country in such a mess and the radio spectrum polluted with non-EMC compliant Power Line Technology (PLT), plasma TVs, switch-mode power supplies, and CFLs (to name a few)? Well, the buck stops at Ofcom. In cases where Trading Standards have sought help, Ofcom have said it's all OK and no laws are being broken, so TS cannot act. In a case where a computer SMPS was reported to TS, they could only act on the Low Voltage Directive and the supplier could only be warned. Had Ofcom used their legal EMC powers, the supplier would have faced court!
If Ofcom had acted correctly over the past 10 years, Power Line Technology would never had left the lab, as it cannot pass the essential requirements unless it is turned off; Panasonic would not be in radio-users' cross hairs over their Viera range of radio-noisy plasma televisions; cheap and nasty switched-mode power-supplies supplied without filtering components would be caught and their suppliers and manufacturers fined; and we would not be calling for Ofcom to be scrapped.
It should be noted that the RSGB cannot take over interference investigation or EMC compliance enforcement as they are not a legally bound entity. There is however, nothing stopping the current government from carrying out their pledge to remove Ofcom, returns its regulatory function to DMCS, and create a new organisation tasked with [radio] spectrum management and EMC compliance. The fines levied on all of the non-compliant manufacturers should fund the organisation for some years!
Re: What's Pi?
"But given the state of geography teaching today, that's a moot point."
I only saw a clip of Educating Essex as it was shown on Anglia News. When the blonde girl, whom I suspect to have been around 14 or 15, suddenly asks what Pi is and where it came from, I realised society is doomed! Another education documentary was asking kids to identify towns from dots on a map. One girl complained that if she wanted to know where Exeter was, she would get on a train. I would have loved to dump her in London and tell her to find her way!
"Kids nowadays eh?"
Quite! My friend's 13-year old son would not walk a few hundred metres along a darkish trackway to meet his father's car, so my friend caved in and went and got him. I used to ride my bike miles out in the country lanes with quite pathetic battery lights - pathetic compared to the LED lights I have today. If I wanted to go somewhere, it was "on yer bike!" from my parents. The afore mentioned friend is older than me, so it's not just the younger generations creating a nation of sissies!
I thought the M in STEM stood for Medicine, as surely one must teach maths as part of Science, and Engineering? At least it was when I studied HNC Electronic Engineering! Why is medicine being missed off? Medical research is an incredibly important part of science and calls on many disciplines.
So I have to ask: Why are we still not teaching first-aid in schools? Why do we have a nation of hypochondriacs who call for an ambulance when they cut their finger? Why does the news have to keep educating people on how to spot certain diseases? Do they forget as soon as they turn the TV off? I see no reason why kids should not be leaving school as fully qualified first-aiders - after all, you can tie biology into the training: here is your blood - it's a good idea to keep it inside. And if the Channel 4 series 'The Sex Education Show' is anything to go by, sex-ed needs a serious overhaul as well
I also feel that maths should teach you how to balance a house-hold budget and explain all of the APR meanings. The applied mathematics I learned for electronics has remained whilst the theoretical stuff has been flushed from the brain. Home-economics should either teach about mortgages and budgets, or be renamed as "Cooking" and taught as such! Biology can teach about bugs and food safety as a tie-in. We clearly need survival lessons and thunderstorm safety as people are still standing under trees and wondering why they get blasted. PE should include self-defence training and swimming. For a country where you cannot get more than 76 miles from the coast, it is abysmal that so many people cannot swim!
Just my 2 pence!
"What kind of mains wiring configuration should be used for testing any kind of mains powered device for CE certification?"
They use a device called a LISN (see http://www.ban-plt.co.uk/tests.php for pretty pictures of how devices are tested) which creates a "clean" mains source which can be tested. Real-world testing in a domestic property would be tricky due to the amount of noise present from other devices. It is ironic that for PLT to work correctly, every other device attached to the mains must comply with the EMC regulations and not introduce noise. When noise is present, PLT fails to function correctly!
"What kind of mains wiring configuration is generally used to allow PLT devices to get their CE certification?"
To gain CE certification (which is worthless!), most PLT manufacturers have used the 'Technical Construction File' (TCF) route to validation. This is where a Notified Body approved to test to CE standards can issue an opinion that the documentation presented before them should result in a product complying with the requirements. At no point is the device actually tested. Result: Gaping hole into which companies can pour electronic junk! For some considerable time, Comtrend PLT devices were being shipped by BT Vision with a totally invalid Declaration of Conformity, yet the bodies responsible for policing this took no action.
As PLT is Data Terminal Equipment (DTE) it is supposed to be tested against EN55022 - the standardised testing for computer equipment. If tested correctly, all PLT devices fail the 'conducted emissions' test due to them blasting high levels of Orthogonal Frequency Division Multiplexing (OFDM) signals down the wires. This act in itself would not be a problem were mains wiring designed to handle radio frequencies, i.e. it was twisted, shielded, etc.. As it is not designed to handle radio frequency energy, it acts as a feeder and radiates the signals accordingly.
Compliance with EN55022 is voluntary, and PLT manufacturers have been trying to confuse politicians (not hard!) and push for their own "standard"; which is now being proposed as prEN50561. This "standard" seeks to increase the limits at which RF interference is classed as unacceptable. If this "standard" is accepted, it will destroy everything EN55022 seeks to protect, and it will no longer be the disgruntled users of the HF radio spectrum that will be annoyed. All radio frequencies will be fair game and you will not have a leg to stand on!
"How does the PLT test configuration relate to the configuration in which the equipment will actually be used?"
The testing environment is nothing like the domestic mains environment, which is full of noise, voltage and phase variations. The test environment is also usually carried out over short runs, whereas the domestic mains wiring looks like a series of aerial feeders, each with their own frequency response and radiation patterns. See http://www.ban-plt.co.uk/reports/RA-report-house-wiring.php to see how well mains wiring in the UK can act as an aerial.
http://www.ban-plt.co.uk/ contains all of the reports Ofcom tried to bury, but were forced to release by the Information Commissioners Office. It begs the question: If PLT is such a benign issue, why are government organisations covering up reports they commissioned in to the effects on the radio spectrum? Why do Ofcom keep saying they can introduce a Statutory Instrument to effectively curtail interference from PLT, yet fail to do so?
The simple fact remains: These devices, and many Switch Mode Power Supplies, Panasonic Viera Plasma televisions and a host of other electronic crud, are flouting the EMC Directive in order to make a quick buck and the UK national regulator (Ofcom) and various government departments (BIS, DMCS) are complicit in allowing this to happen. If you continue to support PLT manufacturers, plasma TV manufacturers, and assorted crud mongers, you cannot complain when everything in your house fails to work due to unacceptable levels of EMC interference!
I worked with Jim
I had the pleasure of working with Jim at Amino; before they shoved 30% of the workforce out of the door in 2009. He is a very nice guy who, despite always being mad-busy, always makes time for you. He explained the issues around the ZX81 crashing (tin plating and no buffers) and confirmed my standard practice of tonnes of Blu Tac as being the standard most people adopted.
A school friend also had one of Sinclair's flat screen TVs and we used it on a (c. 1986/7) school trip to Loughborough Uni to watch News at Ten. We still don't really have pocket TVs in 2011...
Try PLT for a laugh!
You should see what the new VHF-bashing PLT does to airband! Some of the manufacturers have realised they would have to answer to the CAA, so they have quietly withdrawn some models and notched out others. That still leaves the current user-base of both the HF-bashing and the VHF-bashing PLT out there causing problems.
Perhaps when a plane full of people crashes and burns, and the problem was found to be the ILS fsck'd by PLT, the governments will sit up and take notice?! I base this evidence on the A1 at Sandy in Bedfordshire. For years, people died at the cross-road traffic lights, and nothing was done to improve road safety. An MP was killed and a new roundabout suddenly sprung out of the tarmac!
Regulator is ignoring the law!
The sad fact is, many national regulators are complicit in breaking the law by ignoring the EMC Directive (2004/108/CE) and EN55022 whilst using the excuse that it does not need to apply. They are holding up the recommendation 2005/292/EC, which suggests member states should remove the barriers for Broadband over Powerline deployments. It also states that said deployments should still meet the EMC Directive and be shut-down if they cannot. It does not apply to in-house PLT devices; yet the politicians and weasels at BIS (and Ofcom) say and believe otherwise. They state that CENELEC is working on a "standard" to fix all of the problems, whilst obfuscating the difference between an interoperability standard (such as IEEE 802.11) and a EMC testing standard.
The corruption and lack of accountability is mind-boggling! Unfortunately, as the PLT debacle predominantly affects HF radio, the general public do not care!
You can read more about the whole sorry affair at http://www.ban-plt.co.uk/
Been on channel since 1987.
I met some nice people on CB (as well as some a-holes) and I am still friends with some of them. It was a fantastic way for lots of people to communicate - and remember, this was before the days of the mobile phone. You can still have a load of people on one channel chatting to everyone without paying for expensive conference calling; and it used to be ideal when mobile - before alligator-jawed home-base users decided to use channel 19 as their "mother's meeting" channel!
A group of us also marshalled the local town carnival one year. Our point-to-point one-to-many CBs kept working when the local police's UHF radios hit dead spots (a bit like TETRA); so they started relaying messages via us as we stationed mobile units with police officers.
And don't forget "Fox Hunting". Hide and seek in cars (and vans) using the signal to "DF" people in their hiding places. Hours of fun and litres of petrol; with the added bonus that lots of cars and eyes, all in communication, were looking around town for several hours on a Friday/Saturday night!
The problem with AM in the early days was not the power level being used, it was the cheap and nasty electronics used in TVs, etc., which had no RF immunity. Any RF field, regardless of modulation could affect the cheaply built TVs. That was one of the reasons for the EMC directive - to provide protection from and to radio services - though sadly PLT and Plasma TV manufacturers are ignoring it!
RC modellers are not stuck at 27/35 MHz. There are now cognitive radios operating in the 2.45GHz band which offer far greater control and no need to swap crystals!
Sadly, the future of HF is quite bleak. CB, and to a certain extent Amateur Radio, is being wiped off the planet through the deliberate abuse of the HF radio spectrum by organisations and national regulators only interested in making a quick buck. If you are wondering why everyone is being forced to break the law by running powerful linears, go ask Ofcom why they are not enforcing the law against non-EMC compliant PLT filth and faulty plasma TVs?!
10-10 from The Electron
73 de M6PLT
There are other issues which affect ADSL connections out in the sticks. Interference coupled to the over-head lines from electric fences, Power Line Technology and other dodgy mains-powered devices will all affect ADSL speeds. That is why it is so important for communities to hold out for, and demand, fibre to the premises, and not this half-arsed approach of fibre to the cabinet.
FTTC has been announced in the town I live. We will not see any improvement as my line connects directly back to the exchange. It's only Virgin Media with street cabinets around here!
Stuck with Fedora 14...
I use Fedora and Gnome 2.x every day, all day; and I like compiz-fusion, my desktop spinning on a cube, my customised colour scheme and my custom menu items. I tried a test-install of Fedora 15 and Gnome 3 on my laptop and found it horrific. Custom colours gone and replaced with black! Desktop icons gone! No compiz unless you revert to "classic"! And my custom menu items were buggered beyond usage. I don't want a bloody touch screen UI!!
So I am now stuck on Fedora 14, with its packages going out of support 1-month after Fedora 16 is released. Unless I can find a clean way of transferring my customisations to Gnome 3 and setting its menu system back to that of 2.x, I will have to remain on an un-supported system, and that does not sit comfortably with me!
I am not a programmer and I should not have to read the equivalent of War and Peace each time something in Linux is "improved"; that is assuming the developer has bothered to actually write anything?!
Pot - kettle!
It is not just the BBC (or El Reg) who seem to have trouble with spelling and grammar. Plenty of online and print media make silly mistakes, such using metre instead of meter (and vice-versa) and getting the SI units wrong (MHz, not mhz)!
The problem stems from the "education" system. Whilst I was studying BTEC National Certificate and Higher National Certificate in Electronic Engineering, I was pleased to see how each year, we re-visited and revised the previous year's work, then added to its complexity. Schools should adopt this approach when teaching maths and English. You could ask me to 'conjugate a verb', but I cannot remember how!
A little bird told me PLT falls over really well if you use about 50W of SSB around 3.57MHz. Sadly, I am only a CBer, so I don't have access to that kind of kit!
Anyone know where I can get a spark-gap transmitter?
Feet or metres?
I think someone has their units mixed up? My TV aerial in the loft of my house is no more than 4 metres off the ground, which is around 12 feet.
A TV aerial 10 metres above the ground would need a tower to be stable; and that needs a hell of a lot of planning permission and concrete! I had to shell out £190 for permission to put a CB aerial on a 5 metre pole!!
Ban this crap!
It is possible.
PLT launches a considerable amount of RF energy on to the mains wiring. When this energy hits non-linear devices, such as the bridge rectifiers found in Switched Mode Power supplies, it created intermodulation. This can result in spurious harmonic energy reaching frequencies as high as 1GHz (this had been observed and was listed in the recently extracted Ofcom EN55022 test documentation). This harmonic energy is carried via the mains wiring in to devices such as your television, and if they lack suitable filtering components, or those components are failing, the harmonic energy can leak into the electronics and cause problems. It is not a precise science either - the application of a finger, or a test probe, can alter the dynamics and make the problem worse, or disappear altogether.
But who will actually offer me fibre?
It would make sense in my town to ask/force Virgin Media to open its ducts as well!
The copper BT line to my house passes under the street and paths of the cul-de-sac. If the ground-box lacks the capacity for fibre and/or the underground ducts are blocked due to land heave*, someone is going to have to dig things up! There is no room for street cabinets unless you do what NTL did and dig up the paths on the main avenue.
(* This is certainly going to be the case when attempting to run fibre from the ground-box to the homes. The plastic tubes carrying the CW1308 phone cables have been in the ground 25+ years and they will need to be dug up and replaced. With my BT cable running under my driveway and my neighbour's driveway, I cannot see that happening!)
The Virgin Media ducts arrive at the edge of most people's property boundary, which means laying fibre simply requires a route across the garden. It would be a simple job for me to dig a trench through the lawn and run some suitable plastic piping to the house. And I would be prepared to do that myself if someone could offer a decent fibre connection. I do not want to entertain VM's cable modems - I am still burned from the NTHell days and their piss-poor customer service who could not understand something as simple as a lack of down-stream power!
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