Socket to 'em: It's the HomeGrid vs HomePlug powerline prizefight

“Two standards, both alike in dignity, In fair Vegas, where we lay our scene, From ancient grudge break to new mutiny, Where civil blood makes civil hands unclean.” The backers of rival next-generation in-home mains power networking standards may not have come to physical blows in defence of their favoured technologies, but …

[Graham Dawson]

Ok so it took me ages to realise that the odd tweet-counter-looking thing was a link to the comments. Enough with the secret sauce, guys!

The phasing issue the first illustration highlights is uniquely american. It's extremely rare for a domestic supply to have two phases and a neutral to the breaker box. You will see blocks of flats and apartments getting two phases but the individual breaker boxes all have a single phase. Even a lot of commercial isntallations will only have one phase.

Am I the only one that thinks using the CPC as a signalling wire is asking for serious trouble? The whole point of protective conductor is that it only carries current if you have a fault condition in order protect the installation and facilitate ending that fault condition. Quite apart from the possibility of tripping breakers for "no reason", sending signals down the CPC is deliberately introducing a fault current into all the exposed metalwork in the entire installation. A system like that will kill people sooner or later. I don't care if they're saying there's some limit on the current - it only takes one overcurrent at the right time.

And of course the liability for that falls not on the owner, or even the person who sold them the plug, but on whoever installed and inspected the installation.

[Anonymous Coward]

"Ok so it took me ages to realise that the odd tweet-counter-looking thing was a link to the comments. Enough with the secret sauce, guys!"

Took me the time it takes to hover the mouse pointer over the graphic.

[Anonymous Coward]

? Functional earth ? Used everywhere. Most earth wires carry unwanted current which can kill.

[Graham Dawson]

The reason I mentioned the circuit protective conductor specifically and not just "the earth" is because the illustration shows the CPC being used as a signalling bus, which introduces a fault current, which potentially triggers fuses and RCDs and makes the system dangerous in the process. Functional earth isn't connected to the circuit protective conductor and nor should it be - and neither is a functional earth used to protect circuits or prevent the living of exposed metal parts. It's completely irrelevant to what I said because I was talking about protective earthing. And if you can show me a protective conductor that's carrying current in allegedly non-fault conditions I'll be very surprised, because it's both highly illegal and extremely dangerous.

[Richard 12]

Now for the fun bit!

The USA and other places with similar electrical codes are the only place you could use Neutral/CPC like this.

However, many local US jurisdictions now require 5mA GFCI (RCD) circuit breakers in domestic properties - which will definitely trip if a device did this!

(We use 30mA here)

In other words, the only place you could use this - you can't!

The diagram shown is indeed uniquely American. Most would call it bi-phase - the two Lives are 180 deg apart, each 120VAC to Neutral and thus 240VAC from each other. It's done with a centre-tapped transformer, usually very close to the house.

It's also common to have few domestic appliances using both phases - eg tumble driers, ovens.

There are more crazy things over there - "wild-leg" 3-phase is probably the most insane...

[kain preacher]

Split phase

I'm looking at that and shaking my head. It's not two phase but split phase which is single phase. Connect the two hots and you get 220 single phase.

[Anonymous Coward]

Noise

This will inject noise into the ground of most American houses. I would not advise having audio equipment any were near this stuff.

[Anonymous Coward]

new role as embedded networking in ‘smart’ devices.

I think I would base my choice of tech on the TV manufactures choice. Once I had chosen a so called smart tv, I would then purchase my fridge microwave etc etc on the tech in the TV.

[Naughtyhorse]

Re: FprEN50561-1:2012 is not a standard!

By definition it will never meet EMC standards, but a suitably subsantial bung to offcom will deal with that.

I cant really decide if having 2 different standards of stupid is a step forward or back

[Graham Dawson]

Re: FprEN50561-1:2012 is not a standard!

It's a step. That's all that matters.

Celebrate progress! Another step! Onwards to the bright future! It's different!

[Snar]

Re: FprEN50561-1:2012 is not a standard!

Moving towards an inadequately regulated electromagnetic environment in the home where things can no longer be near guaranteed to coexist in harmony doesn't seem very wise to me. Throwing RF around unbalanced and unscreened cables is a wholly flawed idea, requiring an equally flawed specification. Has anyone seem adaptive notching in a product? No? I didn't think so because the cost of implentation would be too high.

What is good for the goose is good for the gander. If I was in the business of manufacturing LED lighting, SMPSU wall-warts etc, I'd be clapping my hands because I would design to EMC levels laid down in prEN50561 and argue that it is just as relevant to my products as PLT and save a shedload of cash by not fitting supression components. The upshot? No more EMC.

People can navel-gaze and whitter on about EMC and PLT being a problem for radio amateurs, but they fail to understand the real scenario. These things have been demonstrated to knock out FM and DAB radio and are of concern to the CAA and GCHQ. A colleague had an issue with LED lighting killing his DAB radio and in the early days of BT's peddling of PLT, they were seen to knock out their own users 27MHz wireless keyboards!

I have had to replace a number of switching PSU's supplied with equipment for linear ones because of interference to HF. Set Top Box PSU's are particularly awful. This is the tip of the iceberg and I am watching with great interest, waiting to hear the whines of fail from people whose radios, TV's or whatever begin to suddenly stop working.

Caveat emptor :)

[Anonymous Coward]

Re: FprEN50561-1:2012 is not a standard!

Can it ever meet RF requirements demanded of "normal" equipment? By design it's a transmitter with a dirty great big aerial.

[TeeCee]

MIMO over Earth.

That'll go down like a lead balloon in much of Europe.

In many countries, even fairly recent build houses commonly have two pin sockets. Those sockets that do offer an earth connection are often earthed to the nearest available water pipe or to a ground pin immediatly outside the nearest exterior wall, rather than there being a contiguous earth circuit around the house.

[The Equestrian]

Re: MIMO over Earth.

In many countries, that neutral line eventually connects to earth as well. If that connection is far enough away it might work, but in Oz that is often at the pole down the street - especially in the outback.

[Tom yng Nghymru]

Re: MIMO over Earth.

How would this effect Voltage Operated Earth Leakage Circuit Breakers (VOELCB)?

These devices were mainly used with overhead supplies with TT earthing (an earth rod in the ground as opposed to having earth supplied by your power supply company), and although they are not installed any more there are still plenty of them in service - most of the house with overhead power around here have them.

They detect a voltage on the earth wire and if present will switch off the supply. They need to be fairly sensitive to work quickly enough to be safe.

[Wize]

I've often wondered about the security of powerline devices.

How do you firewall you mains incomer? What stops your neighbours (the ones on the same phase as you) connecting to your network?

[Aldous]

Re: I've often wondered about the security of powerline devices.

AES pairing between devices and being on a separate electrical circuit usually does the trick

[Captain Scarlet]

Re: I've often wondered about the security of powerline devices.

Normally the powerline devices will pair with the first two devices, once you add more I've had to press the button or tell the atheos software to pair additional ones (Solwise ones I use)

[Paul Crolla]

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.

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...

[1Rafayal]

Re: I've often wondered about the security of powerline devices.

I have used Devolo devices for a number of years.

When I lived in a block of flats, I secured the devices using Devolo's bundled utilities, one of which allows you to secure all of your devices and prevent others from using your network.

I have no idea if I actually needed to do this, but I do know from experience that others using Devolo devices were not able to use my Internet connection (my next-door neighbor).

I dont know if it is safe to assume that other vendors devices also use the same type of security.

[Hayden Clark]

Earth-Neutral bonded

Some installations in the UK have the earth wire bonded to neutral at the point of entry to the premises. So to get any signal down the earth wire is going to need an appreciable amount of power. So these things will be hotter (more wasted energy) and more noisy.

[Andy3]

Crud generators.

It doesn't matter which system they use - ALL homeplug/PLT devices work by injecting large amounts of radio frequency noise onto the domestic wiring, and ALL cause large-area radio interference. It's only about a year since my hobby (amateur radio) was completely stopped by just one pair of these devices installed along the road. Luckily, the fellow was genuinely horrified when I demonstrated what his PLT's were doing and he stopped using them. These things need banning, and quick.

[Anonymous Coward]

Re: Crud generators.

Which "hobby" is more deserving?

[dogged]

Re: Crud generators.

Well no, but by the same token it won't sit there smelling of unwashed crusty radio HAM and talking about the finer points of Klingon etiquette in the 99.999999999% of time that emergencies aren't happening.

How many lives have you saved?

[Death Boffin]

Re: Crud generators.

Five so far. Coming across auto accidents in areas where there was no cell coverage. One was a rollover accident where 4 of the 5 passengers were ejected. Resulted in 1 fatality and 3 airlifted to the hospital. The other was a head on collision with 1 fatality and 2 severely injured. In both cases ham radio cut the medical response time by 20-30 minutes. Look up "golden hour" to see how effective that can be.

[dogged]

Re: Crud generators.

What, is a 999 call from a landline too easy for you?

[dogged]

Re: Crud generators.

Mountain Rescue != Radio HAMs.

But nice try.

Basically, if you can set up a full HAM kit somewhere then you've got power. If you've got power, a landline isn't surprising. If you can't have a landline you'll probably have a satellite phone.

What you won't do is spend weeks upon weeks listening to static and truckers and growing a beard you could lose a goat in.

[Snar]

Re: Crud generators.

You might want to look at NVIS communications - Near Vertical Incident Skywave. It 's a propagation mode where you mount an antenna at near ground level and you launch your power vertically towards the ionosphere. The signal is then propagated back to earth and it's rather like an umbrella effect. Using a decent digital transmission mode (such as Olivia) you can resolve signals -13dB below the noise floor.

From my home in the Midlands, I can reliably communicate with other amateurs across the UK using these propagation and modulation modes and at low powers - sub 10W very easily. I have had contacts at nearly 1000km using 100mW.

I can very easily set up a full "HAM " kit anywhere. I don't need an external source of power and everything I need including a Toughbook computer, transceiver, antennas, modem, poles etc all fit in a bog-standard rucksack.

In deepest Wales where your phone is as much use as a one-legged man at an arse kicking competition and I have my kit with me, I will have comms where you don't.

The comments that you make about listening to static and truckers are so passe. We have heard it all before and just smacks of ignorance.

You might want to listen to this:

http://www.g7ltt.com/audio-files/911r4.mp3

It is about the work that amateurs did 9/11 when emergency comms went off line.

[heyrick]

Re: Crud generators.

"Basically, if you can set up a full HAM kit somewhere then you've got power."

Yeah, could be a Gennie, could be a lead-acid. Could be plugged into the lighter socket...

[Graham Dawson]

@heyrick Re: Crud generators.

You mean you don't have a landline trailed out behind your car wherever you go?

[Anonymous Coward]

Re: Crud generators.

I don't know of many people who would be installing homeplugs halfway up a mountain.

So I don't think you'll have any problems

[Anonymous Coward]

Re: Crud generators.

The amateur bands are provided via international treaties, new allocations are made on a fairly frequent basis, it isn't just about saving lives (although that has happened quite frequently) it's about encouraging people to learn about technology in a way that benefits the whole human race.

There are alternatives for high speed networking, eventually this will be wired into every property from the time its built. Spewing unwanted hash across the RF spectrum is not an acceptable method of bridging the gap until PLC is no longer needed, if the density of the devices goes up then it will become apparent that it isn't just the HF bands that are badly affected.

[heyrick]

Re: Crud generators.

"How many lives have you saved?"

A Ham with emergency broadcast capabilities is much like a spare tyre. Doesn't do anything useful to you for that 99.9'% of the time, but when you need it....thank god it's there.

[Andy3]

Re: Crud generators.

The difference is that PLT devices prevent innocent radio amateurs and short wave listeners from persuing their hobby, but short wave listeners and radio amateurs don't stop computer users from enjoying their activities. PLT is by definition destructive and selfish. A kind of 'I'm alright Jack' device.

[Roar Dehli]

Re: Crud generators.

These PLT crap RFI "terror"-generators needs to be removed from the market because they create a huge amount of RFI-problems for all radio users, including blocking DAB and FM. They are basically illegal devices that do not meet the essential requirements of the EMC-directive. Also, they do not comply with EN55022 class B limits. Regarding amateur radio as a hobby (as some like to point out as a reason that makes it less important than streaming data or watching a RFI generating Plasma-TV etc.) does not mean that the essential requirements of the EMC directive 2004/108/EC is cancelled. All electronic devices must follow responsible EMC design and meet the essential requiremets of the EMC-directive. And using a CAT-5/6 (preferably shielded) for your "hobby" data-network will solve the problem with RFI on HF completely. PLT is a totally unnecessary device creating nothing but troble (same story with Plasma-TV's). The final decision for FprEn50561-1 is held back by the EU commission EMC-expert that refuses to approv it, because it allows higher levels of RFI than any earlier standard. FprEN50561-1 is basically a flawed proposal that wants to allow 1000 times higher levels of RFI on HF. I say remove PLT from the market permanently ! We dont need it.

[Twilight]

Re: Crud generators.

You do realize how hard it is to run CAT 5/6 in a lot of older buildings, right? That is the huge advantage PLT has over ethernet.

I completely disagree with you on Plasma TVs. They are superior to LCD TVs (and the so-called "LED" TVs) and I will continue buying them until something better comes along (hopefully OLED will show up one of these days and blow everything else away). I have not seen any radio interference from the Plasma (admittedly I also don't listen to FM much or operate a ham). Most microwaves put out far more interference than a Plasma TV.

[Roar Dehli]

Re: Crud generators.

Running CAT5 in older buildings is not impossible and can be done if you must. It may take drilling a few holes in a wall or two, but that is easy even in concrete walls. An electrician will do this easily, and the installation will look professional. Besides, CAT5 outperforms PLT so you will have a much faster network. Introduction of noisy RFI generators like PLT is not justified because of the terrible radio interference they create to nearby radio users/listeners. But of course, it is easy to dump the shit on someone innocent like your neighbour who might be a radio user, and then ignore the problem. A very decent way to behave......

Plasma-TV may have a better picture (regarding black levels, which is very black), but in the last few years the OLED or LED TV's have excellent picture quality, so now they outperforms Plasma-TV's. Take a look at the new Samsung 46" ES8005 LED series which is excellent. And they have no RFI problems and uses only 82w (very power efficient). Plasma-TV's uses twice that or more.

Plasma-TV's have huge problems with RFI, especially in the LW-MW and low HF frequency range.

Most of them does not comply with the essential requirements of the EMC directive 2004/108/EC.

http://www.youtube.com/watch?v=rc6hNkjG9gE

http://www.youtube.com/watch?v=TOQ-IUSRr2E

Since there are no EMC-standard for RFI emitted directly from the Plasma screen below 30 MHz, the TV industry have ignored the problem, sending these RFI generators onto the market. Below 30 MHz there is only conducted emissions from the primary side of the TV power cable (AC mains), which is limited by EN55013 I believe. But in a test of RFI directly from the Plasma screen, most (if not all) plasma-TV's have strong RFI, even at 100 or 200 feet away from the TV. The videos abowe demonstrates a 47" Samsung plasma at 200 feet (60-70 meters) away from my wire antennas.

http://www.etsemc.co.uk/wp-content/uploads/EN55013.pdf

[Graham Dawson]

Re: Crud generators.

Twilight, you're assuming that the wiring in your older building will be up to the required standard. Often it isn't. I could tell you horror stories about the wiring in ostensibly refurbished old buildings and I can tell you right now that none of them would have supported any sort of PLT installation. Wireless repeaters would be more reliable. Given the cost of having to strip and replace all the wiring to make PLT reliable you'd be as well to just install cat5/6 alongside anyway. You'd get a more reliable, higher bandwidth signal and more scope for modification in future if you leave in enough redundancy. Plus you can run phones down it.

[heyrick]

Re: Crud generators.

"You do realize how hard it is to run CAT 5/6 in a lot of older buildings, right?" - yes, like this place, installing wired ethernet is not the most viable idea. So I use WiFi. There are blackspots due to four-foot-thick stone walls, so I can't read El Reg on the bog; however WiFi repeaters/extenders, or sticking something in the loft would get around that a hell of a lot more simply than rigging up wires. I also get the portability that WiFi offers. Plus, the microwave interferes with WiFi...not the other way around.

[Corp-Rat]

PME

Can't see this MIMO system working too well on TN-C and TN-C-S systems in use in the uk.

how well does data travel on a shorted pair of wires?

[Gary 6]

Powerline Atmospheric Polution.

I wonder if many people, other than those immdiately affected by this polution , realise how much grief this causes to the radio fraternity. That does NOT mean just radio amateurs, but the new Digital Broadcasting on FM.Anyone doubting this should viist UKQRM, a siote run, not by nutters, but very knowledgable guys, some professionals in the field of wireless (used advisedly!) communications. Even those" professionals " employed by ofcom to supposedly regulate and enforce the theoretically draconian powers which such a regulator in theory has, lack very often either the knowledge or genitalia to do thier job! Thsi prob;lem is indeed universal, affecting most of europe and much of North and South America. The line is fast being approached where, if remedial action is not taken by ofcom or some other authority, lives may be lost or "corrective action" taken by those most affected by this scourge. Regards, Worried Pissed Off, UK

[R-J]

Re: Powerline Atmospheric Polution.

These devices are illegal to use!

The draft standard CENELEC FprEN 50561-1 has not been approved yet!! The PLC lobby has been putting out false information claiming that it has. The European Commission will not list a harmonised standard based on the draft because of serious objections from no less than, the EMC consultant of the European Commission, and from others involved in radio communication. The EC EMC consultant maintains that the draft standard does not meet the EC's EMC directive's essential requirements, which were designed to give reasonable protection to the RF spectrum. So, there is a stumbling block whereupon using these devices will actually mean breaking the law, because the published standard EN 50522 has been deemed applicable to these devices and PLT system emissions greatly exceed the limits set down in EN 50522.

[Dazed & Confused]

Your iambic pentameter is off

You've lost a syllable in the change from Verona to Vegas.

Shakespeare would be rolling in his grave.

I expect it's under a car park somewhere.

[graeme leggett]

Re: Your iambic pentameter is off

"Las Vegas" would have scanned but I suppose the Fa...Ve... semi-aliteration (or is it assonance? ) would have been broken up

[John Brown (no body)]

Re: Your iambic pentameter is off

To be fair, if the sub-ed had the skills of a Shakespeare s/he'd not be the sub-ed on El Reg.

[Northumbrian]

Re: Your iambic pentameter is off

We don't know what Shakespeare had to do to survive in the early years - jobbing extra was merely one. Maybe subbing was another ...

[Anonymous Coward]

Sending signals down the ground wire?

How is that possible?

Also, it may get round surge protectors but does it compromise their protection?

[Anonymous Coward]

The needs of the many............

[James 100]

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 ;-)

Personally, I'm interested in the G.hn coax option, running a gigabit or so up the disused drop of coax Vermin Media left between floors a while ago. (Yes, having cat 6 would be nice, but I draw the line at drilling through walls/floors myself. I'm guessing once I have a few hundred quid lying around I could get a local electrician to poke a dozen drops down from the attic and stick a GbE switch up there, but until then I'll stick to the Solwise powerline stuff.)

[PyLETS]

Another approach - plastic optics added to standard mains power cabling

I've had cat 5e in most rooms in my house for about 10 years now, one of the best investments ever made. However, this allows only 1 or 2 networked devices per room. A standard suitable for just about every electrical device being networkable without drowing us in interference must involve adding plastic optic fibres designed for easier termination to mains cable as manufactured and fitted into new homes. It's the standard plugs and sockets which need upgrading, maintaining backwards compatibility, to include a data path.

[Michael Wojcik]

Re: Another approach - plastic optics added to standard mains power cabling

I've had cat 5e in most rooms in my house for about 10 years now, one of the best investments ever made. However, this allows only 1 or 2 networked devices per room.

How are you restricted to one or two devices per room? Just pop a hub or switch in the room if you need to connect more. The physical topology of twisted-pair Ethernet is a tree - there's no need for each device to have a home-run line to a single hub.

[Mage]

Who cares which is better?

They are both spawn of Satan and need to stop lying about

1) Immunity to RFI needed.

2) The amount of RFI they produce.

If tested properly, both are illegal.

[Anonymous Coward]

How often doesn't it work?

In times past, when I worked on these systems, a major problem was the range being very unpredictable. In some cases, a signal wouldn't travel 2 metres. In another case, the signal in a block of flats appeared in just about every unit on the same phase. I came to the conclusion, that these were "a very bad idea". The range also changes with the circuit loading. I recall doing the spectrum analyser tests on operating systems and the results were extremely variable and often outside the specified limits. Running a circuit analysis on a theoretical power line model shows quite some quite interesting performance anomalies are possible due to cable characteristics, reflections and standing waves. It is not possible to stop modulated power lines from radiating, so I can see why radio amateurs hate them.

[Will Godfrey]

First, I am not a radio amateur. However, I am reasonably technically competent and experienced. When I first heard of these my instant reaction was one of disbelief that wide-band jamming devices were now (apparently) legal. Nothing has been said since then that changes my opinion.

[Destroy All Monsters]

Yes, Great Galactor! Jamming of Earthlings' communications *will* proceed soonish.

We have several so-called "companies" working on this. No-one suspects the horrible truth.

All is going to plan.

[across the pond]

Some factors to consider regarding data over power line.

G.hn was originally sold in the US under the DS2 Universal Power Line Alliance brand. I guess HomeGrid is just a rebranding of the upgraded DS2 product line. As far as my research has shown, the only company that embraced DS2 back in 2007 was Netgear. Netgear eventually began offering Homeplug devices and discontinued DS2 technology.

Unless you live across the pond here in the US you are probably unaware that the National Electrical Code was updated to require Arc Fault Circuit Interrupters be installed on most circuits feeding outlets in all new residential installations after 2008. When I moved into this house which was constructed in 2005 my HomePlug adapters did not function properly when used in any bedroom. It turned out that when the house was constructed in 2005 the NEC required that AFCI's be installed in all circuits feeding bedrooms. I was using a bedroom as my home office. The AFCI's in my electrical service panel were manufactured by Siemens. Unfortunately General Electric and Siemens Arc Fault Circuit Interrupters severely attenuate RF. AFCI's manufactured by Square D and Eaton Cutler Hammer pass RF without attenuation. I replaced the Siemens AFCI's with Eaton AFCI's. Unfortunately those responsible for writing the AFCI standard did not specify RF attenuation limits. MIMO technology was introduced to eliminate the attenuation between the Hot and Neutral conductors caused by certain AFCI's. The third Ground (Protective Conductor) was mandated in the mid 1960's and does not pass through the AFCI. The only way to transfer the RF signal from a HomePlug or G.hn adapter would be to transmit the signal between the Hot and or Neutral and the Ground conductor. The only question is how to prevent an appliance with a metal cabinet like a refrigerator or Microwave from becoming an antenna for HomePlug or G.hn signals because appliances with metal cabinets have the protective ground conductor connected to the cabinet. By the way according to the NEC the only place the protective ground should be connected to the neutral conductor is at the electric meter. The earth ground rod is also required to be connected at that same terminal.

[Zola]

I'm confused - AV2 is already here

This article repeatedly states that "AV2 is imminent" and "AV2 is not here yet" however AV2 (500Mb/s) Homeplug kit has been available for well over a year (in the UK, at least).

So is this article referring to something other than AV2, or is it referring to an updated version of the current and in-the-shops version of AV2 (ie. AV2++, AV2.5 etc.)?

As for AV2 vs. G.hn, since the former has been available for so long, the equipment is cheap to buy and seems to offer all the benefits of G.hn, I really don't see the point of introducing another, different, data-over-mains "standard" - it's like Blu-Ray vs. HD-DVD all over again (although I don't see the late-comer to the marketplace being victorious this time around).

Also another note, Broadcom seem to have ended further development of their Gigle-based units, which were taking an absolute battering in the marketplace from Atheros-based AV2 kit.

[MacroRodent]

What's the point of either standard, given ubiquitous WLAN?

Just wondering. Almost all computers, mobile phones and damn near any other kinds of electronics come with built-in WLAN these days. Any kind of wired connection is just extra hassle, even at home. I often see family members carrying the laptop upstairs or downstairs while it streams video. My kid would probably think I have gone nuts (or more nuts than usual) if I insisted the computer has to be plugged into the wall socket to access the net.

Wired connections are sooo 20th century!

[Zola]

Re: What's the point of either standard, given ubiquitous WLAN?

Try living in an apartment block and see how well WiFi performs at streaming when every channel is in use, sometimes by more than one neighbour. The fact of the matter is that WiFi doesn't work in congested areas (and if it does work, it is unreliable), when Homeplug performs flawlessly come what may (and offers superior performance to even the best 11n WiFi).

[R-J]

Re: What's the point of either standard, given ubiquitous WLAN?

So, to check I've got this right, 2.4GHz WLAN has 10-14 channels, although technically fewer are usable in any one location due to overlapping, but PLT has effectively just one channel; in reality a spread of OFDM carriers. What happens when several neighours start using PLT? Is this not likely to impact severely on data rates?

[Mayhem]

Re: What's the point of either standard, given ubiquitous WLAN?

Simple. Concrete walls & floors.

I have tried all kinds of wireless and wired connections in a range of flats in the UK. Most fall foul of the fundamental issue that they tend to be long & thin layouts, with thick concrete or brick walls between rooms which severely affect wireless signals. And often it is exceptionally difficult to run a wired cable between rooms - the landlords tend to get grumpy about concrete saws or drilling, and one even refused to allow cables tacked around the door frames.

Compared with back home where we build in timber, and running cables is trivial, I can completely understand the desire for PLT. Ring mains on the other hand still depress me - half the wiring in this country is practically stone age.

It is also a particular problem for properties looked after by bodies like English Heritage or the National Trust, who are explicitly forbidden from modifying the buildings if they can help it. Assuming the building has an electrical system in the first place, PLT technology has been extremely useful to them.

[JaitcH]

Never count on the presence of an earth/ground line

Many countries don't have grounds/earths but they DO have ground trip breakers in lieu of.

With the advent of plastic water pipes, creating a chasm between the street water main (which are also increasingly plastic) many grounds are dependent on ground spikes driven into the ground and saturated with copper sulphate, etc.

There is an assumption of continuing moisture to maintain the conductivity - again this might be lost when the area surrounding a ground pole is covered with concrete!

In North America, as well as large chunk of Japan, two phase + ground (120-120/240) is used and although the 240V phase-phase is used for cookers/stoves and laundry driers, as well as central air-con systems, phase-neutral (120V) is used for regular outlets and connected to achieve balanced loads.

Ontario, Canada, had a 'gold' kitchen system whereby a double outlet would share the neutral line but each half of the double outlet would be connected to different phases,

This means that both HomeGrid and HomePlug would need to have sufficient power to reach the the other phase - via a street transformer - or some cross-connection between phases would be needed to enhance transmissions.

[Anonymous Coward]

Still rumbling on...

PLT is a convenient product so i suspect is here to stay, the proposed standard is just an excuse for not meeting the same performance as every other manufacturer of mains powered equipment. It makes a mockery of current interference protection measures for all types of radio services and will only become worse as performance of PLT devices speeds up.

I think the regulators e.g. Ofcom, the European Commission and the FCC are making a serious error of judgement in allowing PLT not to have to comply with EN55022 emission limits.

You would have thought the FCC in particular would have learnt from the Lightsquared v GPS debacle when it comes to protecting adjacent services but apparently not...

[Anonymous Coward]

Cat-5e is SO MUCH BETTER

and it doesn't create wide-band RF interference.

We used to have standards against idiots inflicting RFI , along with a general dumbing down and idiocy we get from Central Govt now , RFI standards seem to have gone to pot too.

[Anonymous Coward]

Sometimes the only solution

I hate these things based on this selfish blasting of noise across Medium Wave and Short Wave. Just don't understand how this kind of illegal kit can be allowed. And it is getting worse - with all these YouView boxes being handed out by the ISPs many of them are supplied with very cheap Powerline kit.

Trouble is there is sometimes no choice. I look after home users. And they are often in a rented property, so no drilling walls for cat5e. (Hands up those who have tried to drill a wall made of flint?) Running loose cables around trip people up. Clients rarely want to let me run cables around their house, or from front room to bedrooms. Not only due to them looking ugly but they can be a trip hazard when you are not allowed to nail them to the wall (rented property).

WiFi can be impossible in flats and dense population centres. One client of mine could not connect to his WiFi router sitting on the same DESK as his laptop!! Turned out there were SEVENTY different wireless networks blasting over his house!! it is not unusual for me to find 20-25 networks in this city, but 70 just amazed me.

Many walls contain tinfoil or metalwork anyway. Some locations can just be bizarre as to how wireless fails to migrate around. Especially older buildings. Coverage will fail to get round a property for no obvious reason. There are only so many repeaters you can install.

So frustratingly I am sometimes forced to use these evil power line adapters. Though I will do my best to check out the local roofs for big aerials. I have refused to install for at least one client when spotting the HAM aerials next door.