Power Line Networking - some thoughts
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Power Line Networking - some thoughts
PLN is a growing area of research and development. I have 2 adapters running successfully. The frequency used lies in the 'short wave' and is the subject of some unsuccessful lobbying by radio hams due to interference on that band.
The latest move is into the VHF spectrum, up to 300Mhz. Here the prospect of interference becomes more of a nationwide issue. This video, although not particularly scientific, is effective in showing what might happen, and it is of interest that some of the frequencies onto which the technology may move could interfere with 'advanced' broadband distribution, eg VDSL. OfCom have produced a report.
The latest move is into the VHF spectrum, up to 300Mhz. Here the prospect of interference becomes more of a nationwide issue. This video, although not particularly scientific, is effective in showing what might happen, and it is of interest that some of the frequencies onto which the technology may move could interfere with 'advanced' broadband distribution, eg VDSL. OfCom have produced a report.
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I can't believe he was called Nigel........Not really explaining anything there. For example what distance was that interference experienced at? Is it only interfering with localised radio's etc? Is it just those items on the same electrical circuit or will next doors radio be affected?
Please make it brief as Nigel has just bored the pants of me!!
Please make it brief as Nigel has just bored the pants of me!!
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The frequency used lies in the 'short wave' and is the subject of some unsuccessful lobbying by radio hams due to interference on that band.
Equipment shall be so designed and manufactured……..to ensure that ……the electromagnetic disturbance generated does not exceed the level above which radio and telecommunications equipment …… cannot be operated as intended (Essential Requirements (1) in Annex 1, relating to Article 5 of the Directive)
Furthermore, although the PLA units, as measured by RSGB and other test houses, are helpfully notched to minimise interference in the amateur frequency bands, they nevertheless produce conducted emissions which will result in interference across much of the rest of the HF Radio Spectrum. The conducted emissions significantly exceed the limits defined in the benchmark relevant international standard CISPR22 (Harmonised EU Standard EN55022).
full article here on the RSGB web site Power Line Telecommunications (PLT) news page | Radio Society of Great Britain
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Originally Posted by Call100
Is it only interfering with localised radio's etc?
I agree 'Nigel' should have had some half (heck, why not completely) naked ladies to spice up his video
Some of the PLN trial is now apparently up in the low GHz band (2-3).
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Not-very-interesting-fact-of-the-day...
I used to work with the guy who invented Powerline. The earliest trials had lamp-posts in Manchester delivering an unhealthy amount of radio interference.
I used to work with the guy who invented Powerline. The earliest trials had lamp-posts in Manchester delivering an unhealthy amount of radio interference.
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Our local club has donated £1000 to the RSGB fund to fight against PLT devices that don't meet the EMC directive. Of course it does raise the issue as to how the rogue units managed to pass the tests in the first place. It has been found that many of the units examined, at one stage had unfilled spaces for filtering and other components. That suggests that they might have been fully populated when they were tested, and then the production units were produced without certain items.
During one of the recent demonstrations at our club. It was found that modern units do seem to be within the specifications of the directives. So maybe we are seeing things turning a corner, and the problem of PLT devices will go away. What happens to the money that people have put into the spectrum defence fund is likely to be used in future battles that we will inevitably face from new 'toys' that come onto the market.
Astral
During one of the recent demonstrations at our club. It was found that modern units do seem to be within the specifications of the directives. So maybe we are seeing things turning a corner, and the problem of PLT devices will go away. What happens to the money that people have put into the spectrum defence fund is likely to be used in future battles that we will inevitably face from new 'toys' that come onto the market.
Astral
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I don't know where they are, but out here in rural Suffolk I can hear gently warbling carriers all over the 430-440 MHz band. They are coming in off the aerial (removing it removes them) but are clearly not amateur. They aren't as rough and unstable as SMPS noise, but as to what they are...
Some time when I'm bored, I'll go out and DF them.
PLT should never have been invented! Stick it in coax and send it underground, I say.
Some time when I'm bored, I'll go out and DF them.
PLT should never have been invented! Stick it in coax and send it underground, I say.
CAA are definitely somewhat unhappy. With them going up to 300MHz and beyond, the cumulative effect of a lot of them could make ILS useless when landing on 27, plus problems for comms.
Plus the effects on social alarms at VHF - the 'granny necklace' that she pushes the button on when she falls over, and remote monitoring of pacemakers etc.
Plus the effects on social alarms at VHF - the 'granny necklace' that she pushes the button on when she falls over, and remote monitoring of pacemakers etc.
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keef
Are those 430 MHz warbles an harmonic of other transmissions ? - What are the propagation modes for this frequency - line of sight I would imagine. Is there special range equipment for tracing weapons drops etc.
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Originally Posted by Keef
out here in rural Suffolk I can hear gently warbling carriers all over the 430-440 MHz band. They are coming in off the aerial (removing it removes them) but are clearly not amateur. They aren't as rough and unstable as SMPS noise, but as to what they are...
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Oh yes, the band is certainly shared. But I'm getting LOTS of unmodulated carriers, warbling slightly. They could be umpteenth harmonic of something lower down the spectrum, but what would produce so many of them?
When I'm bored some time, I'll go out and DF them.
When I'm bored some time, I'll go out and DF them.
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PLN is a growing area of research and development.
In the cabled world, fibre is the future. Much R&D effort is going into continually driving down the costs. The more near term future is driving down the cost of 10Gb copper for various applications.
Wireless technology will continue to develop, but will never replace physical infrastructure.
Spoon PPRuNerist & Mad Inistrator
In the cabled world, fibre is the future. Much R&D effort is going into continually driving down the costs.
100Gbps over SMF up to at least 40Km - that's a nice prospect.
SD
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100Gbps over SMF up to at least 40Km - that's a nice prospect.
Powerline technology has always been, and will remain niche residential market technology for the home-owner to play with on the weekend. It's never going to get any traction in the business world, and therefore any interest in ploughing R&D funds into it is unlikely, and whatever limited investment does happen is going to be purely for the low hanging fruit manufacturers.
(all my own personal opinion of course.....)
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Fiber is still the most promising high-speed, long-distance networking technology. Mixing network traffic with power distribution is a fundamentally bad idea and it rather surprises me that anyone has even implemented it. It has the same safety margin as, say, changing all the working voltages on a motherboard to plus or minus 240 VDC.
Superimposing a tiny, precise data signal on a huge, imprecise, high-powered power distribution circuit? The whole idea makes me nervous—no thanks. I'll keep the ADSL line.
Superimposing a tiny, precise data signal on a huge, imprecise, high-powered power distribution circuit? The whole idea makes me nervous—no thanks. I'll keep the ADSL line.
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Originally Posted by mixture
In your personal life perhaps, but not in the world at large.
Until the coalition get their ducks in a row and sort out the BT side of things so that we can develop a national cohesive network based on fibre there may well be PLN broadband distribution to rural areas.
I have been whinging at OfCom and Mr Vaizey to grip this BT thing or we will finish up with umpty dumpty different distribution systems all over the UK, few of which will be 'compatible' in terms of creating a uniform national distribution system. What BT appear to be doing at the moment is waiting until a rural community self-funds an expensive alternative distribution, and then nipping in and undercutting with a fibre supply - which I think is a deplorable practice and needs urgent government action.
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Saab
Please correct me if I'm wrong, but in the 50' and 60's, did not the old CEGB have a data messageing system that was based on superimposing high freq signals on the wires that carried the grid. An old example of powerline networking - Analog I think.
CAT III
(As usual off topic.)
CAT III
(As usual off topic.)
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As well as PLN there are trials of running fibre ALONG the power line network. There are trials in place of both.
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there may well be PLN broadband distribution to rural areas
I suspect you'll more likely see flying pigs before you see Cisco Systems or Juniper Networks start bringing out carrier kit to drive PLN networks.
I understand the issues facing the rural divide, I really do. However PLN is not the answer. Fixing the number of issues constraining fibre deployment (e.g. the taxation of dark fibre by the government etc etc) would be a much more productive use of Mr Angry from the village letters.
As tempting as it is, I'm not going to be drawn into the old BT debate. But briefly, I think competition should be encouraged rather than "doing something about BT" ... which will probably only end up giving them another pie to stick their fingers into.... just like their artificial chinese walls that they operate at the moment ! BT need to learn the hard way.
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PLN (BPL) appears to be a failure in the USA. As I understand it, the last trial system has been shut down. It required too many repeaters to be economical in rural areas. Other methods such as ADSL, TV Cable and FioS (fiber) have won in urban areas.