HomePlugs - Ethernet over Power

It would appear that BT are removing threads from their forum if they document evidence of interference, such as this one which no longer exists...
http://beta.bt.com/bta/forums/...jspa?messageID=39342
So it seems they may be actively suppressing evidence and, given their position, this may make it difficult to get local evidence.

Looking at their mode of operation, any physicist will tell you that RF emission is inevitable, the only question is how much effect it has.

I used ethernet over power plugs for 18 months until for some unknown reason, they stopped working. Replacement units still didn't work, so I spent a lot of money having a cable installed - drilled hole in concrete floor slab, fed cable through light fitting holes in the ceilings of 2 bedrooms, a laundry & store room below, through holes around air-con ducting, through into the garage, back through the wall into the study.....

I honestly can't hear any difference to the sound when compared to the power line adaptors.
Well, by that, I mean when they were working!

 Blythe,  its not so much what it sounds like for you, I have no doubt they work well;  its the effect they have on other equipment & in particular the local area.  With some radio frequencies reception & broadcasting is seriously affected & GCHQ has published concerns that they can affect its ability to monitor radio activity in the UK & as such are a security issue.    

For non-brits GCHQ is the UK Government Communications (HQ),  they listen in to worldwide radio traffic for national/international security,   working with other such orgs like CIA etc.

I've run EoP since moving into my house 5 years ago. Didn't experience any issues until recently when my wifi network had become very erratic - disappearing then reappearing again. I also had issues with my sonos surround system dropping out. 

This morning I pulled all the EoP plugs from the house and have moved my wireless routers around to try and get a better wifi coverage through the house. So far so good. Will be interesting to see how an extended streaming session to the hifi goes tonight - as of last night the situation was rendering my 272 useless.

Mike-B posted

 I read somewhere that Ofcom (UK regulator) are looking into the pollution/noise issue & may bring controls, legislation & bans. 

 

No this is not true, although there are quite a number of radio amateurs who wish it was. If the devices are properly CE marked, then Ofcom can't ban them or legislate about them, even if it wanted to, which it doesn't. If one is faulty and causing harmful interference to a licensed radio system, then that is another matter of course.

As an engineer, I hate the concept of EOP, but if the power supplies in the hifi are designed properly, which I would hope Naim's are, then I really have difficulty seeing why there should be an effect on sound quality.  I am much more ready to believe the use of EOP could affect wifi performance, although it will depend on the exact EOP devices.

best

David

Mike-B posted:

This morning I received an e-mail from BT pushing their HomePlug (EoP).   I also made an enquiry this week about a TV/Sport package & was told the standard engineers install kit includes these things.  .........  NO I'm not !!!

  Does anyone know what the latest is on these things?   I think most peeps on the forum say they pollute your house & nearby neighbourhood mains power & introduce noise into your audio. OK, this all may be true, but is it based on the situation as it was with EoP adaptors a few years ago or is that true of the latest equipment.   So my question is what is actually going on in 2016 ?   I read somewhere that Ofcom (UK regulator) are looking into the pollution/noise issue & may bring controls, legislation & bans.  Also some other countries have bans in place already.  Looking around www I can't find anything new on this & now it seems the UK's principle telecoms provider is pushing these things & as the principle telecoms provider - like BBC with DAB - "it must be a good" & as the average punter knows no better & asks no questions we are liable to have them installed all over the place.

So any news, any up to date www links, any regulations & compliance controls ---- all gratefully received.  

Mike - pollution is an interesting term - its the term I do use, as the by-product caused by using these devices produces indiscriminate un intended consequences just like pollution.

Power line over ethernet effectively uses wideband RF modulation of the mains with thousands of tiny - what looks like phase modulated - RF carriers. Because of the nature of physics an RF power applied to a wire will radiate - its how radio works.

Now each tiny carrier is very low power - but aggregate up across all carriers is not insignificant in my opinion. Also because the mains wiring is essentially non resonant it tends to be near field emission that are caused rather than far field emissions, but you can certainly notice the increased noise from many such emissions from many miles away.

So if we focus on the near field emissions - and these will vary depending on the largest length or radiating wire and bandwidth but typically well within the wavelength (r << λ). Now PLA starts at around a wavelength of 80metres. So within this distance (and remember the higher frequency carriers will be smaller distances) the near field emissions from the mains cable will be coupling into other wires, electronics and such link. This is effectively RF noise. For low noise electronics applications such a high quality audio replay this will almost certainly be polluting.

Of course there is the direct RF noise on the mains wire from the PLA  that directly couples through to our electronics as well.

Now more recent designs have had to cope with various issues such as suppressing the use of reserved radio spectrum and reserved users like the MoD, radio amateur licence operators, the CAA etc as well as broadcast transmissions are now protected. Additionally effort has been applied to reduce noise, by lowering power and reduction of standby noise - but they are still bad in my book - and I am not happy with the possible health issues of wideband low power near field emissions from unshielded domestic wiring - especially in bedrooms with there is increasing concern about low level wideband RF exposure to our brains when we are sleeping.

But as these studies are ongoing, and the latest devices kind of fall within the EM emission standards (but depends on mains wiring!!)  and most people don't have high quality audio equipment or other sensitive electronics so they are legal... BTW CE marks dont really mean much - to progress against a faulty device in appropriately using a CE mark you have to progress via trading standards and not Ofcom!!! -i in my experience trading standards just don't have the knowledge or skill or resources to deal with. All Ofcom can do is ask you not to  use the PLAs in certain cases - and indeed 'I have first hand experience of this and all parties thankfully cooperated.

Also Ofcom has moved on and to me is more focussed on the commercial exploitation of radio bandwidth  rather than protecting the radio spectrum for all users.. and radio interference from radio/TV reception services for Joe Public for example has been off loaded to the BBC and its is hard work progressing any complaint.. you really need to be a licensed user to get any traction with a RF noise complaint in my opinion...

Simon

Simon-in-Suffolk posted:

 

Now more recent designs have had to cope with various issues such as suppressing the use of reserved radio spectrum and reserved users like the MoD, radio amateur licence operators, the CAA etc as well as broadcast transmissions are now protected. Additionally effort has been applied to reduce noise, by lowering power and reduction of standby noise - but they are still bad in my book - and I am not happy with the possible health issues of wideband low power near field emissions from unshielded domestic wiring - especially in bedrooms with there is increasing concern about low level wideband RF exposure to our brains when we are sleeping.

 

Simon

 

Hi Simon - This is a really interesting point - one of the reasons I went EoP was because the internet connection comes into our bedroom and I was concerned about having a wifi router close to the bed. But from what you're saying, it sounds like it is the lesser of two evils, rather than having EoP running through the mains around the bed.

Yes - I would have all devices; mobiles, PLA, wifi out of my bedroom or at least switched off at night.. but out of those three internal wifi is probably the one I am least concerned about. Relatively low power, high frequency and relatively narrow bandwidth, and antennas and devices are more easily distinguished.

Simon-in-Suffolk posted:

n....................   and I am not happy with the possible health issues of wideband low power near field emissions from unshielded domestic wiring - especially in bedrooms with there is increasing concern about low level wideband RF exposure to our brains. 

Thats an new angle I have not heard/read before on EoP devices.   

As for Ofcom,  next best to useless I fear for this type of thing if they've moved off into other directions who will be over looking the area of RF pollution.  I wonder if the EU will move into this - if they do,  I expect it'll take forever.  So as much as we spin this wheel it'll probably come back to & be quicker with self policing & technology advances in that industry.  

Mike - when I was a little involved with this a few years back, the EU was pushing for adoption of the PLA devices for consumer but were up against the European Electromagnetic Compliance groups - hence I seem to remember some of the compromises..

Mike-B posted

As for Ofcom,  next best to useless I fear for this type of thing if they've moved off into other directions who will be over looking the area of RF pollution.  I wonder if the EU will move into this - if they do,  I expect it'll take forever.  So as much as we spin this wheel it'll probably come back to & be quicker with self policing & technology advances in that industry.  

Ofcom hasn't "moved off into other directions". It's a consequence of the single EU market. If the device conforms to the relevant harmonised European standard as regards the EMC Directive then Ofcom can not by law choose to ignore that.

best

David

Simon-in-Suffolk posted:

Yes - I would have all devices; mobiles, PLA, wifi out of my bedroom or at least switched off at night.. but out of those three internal wifi is probably the one I am least concerned about. Relatively low power, high frequency and relatively narrow bandwidth, and antennas and devices are more easily distinguished.

Our dog has slept under the bed since we moved to the new house - I was wondering what had caused the slight abnormalities..... 

David Hendon posted:

Mike-B posted

As for Ofcom,  ............   if they've moved off into other directions .............  

Ofcom hasn't "moved off into other directions". It's a consequence of the single EU market. If the device conforms to the relevant harmonised European standard as regards the EMC Directive then Ofcom can not by law choose to ignore that.

That was my comment on Simon's post  "..Ofcom has moved on and to me is more focussed on the commercial exploitation of radio bandwidth  rather than protecting the radio spectrum for all users.."

A link to the amateur radio worlds interests on this subject     http://www.ukqrm.org.uk/

David Hendon posted:

Ofcom hasn't "moved off into other directions". It's a consequence of the single EU market. If the device conforms to the relevant harmonised European standard as regards the EMC Directive then Ofcom can not by law choose to ignore that. 

David - it is or was not as straightforward as that as there was debate and lack of consensus on which EMC Directive applied...and it really seemed to depend from what I saw which lobby group you formed part of...  the issue was that radio transmission from the attached mains wiring was an unintended consequence of PLA operation and this was the one of the key issues - and EMC compliance test results seemed to vary on the wiring used - and this is or was not standardised - i.e. there is not a Euro house.

Some of the EMC results i saw, of yes devices a few years old now, were quite shocking..

Mike - I used to be a member of UKQRM - and the main issues were about radio reception and listening as an unprotected user. Radio amateurs are protected and their frequency bandwidths have become gapped and so less an issue as being licensed they are protected by Ofcom. It was more the long distance unlicensed radio listener - yes a niche pursuit - probably even more niche than quality hifi - but it appeared no one was interested in protecting these users , and many were newcomers to the UK who used SW to listen home where internet radio was not suitable or available. There were several discussions between UKQRM and Ofcom on this... but the sentiment was I felt that Ofcom felt the hands were tied by EU legislation for unprotected radio users... and being cynical there was perhaps no money in protecting this small  group.

Simon

Harty601 posted:

Simon-in-Suffolk posted:

Yes - I would have all devices; mobiles, PLA, wifi out of my bedroom or at least switched off at night.. but out of those three internal wifi is probably the one I am least concerned about. Relatively low power, high frequency and relatively narrow bandwidth, and antennas and devices are more easily distinguished.

Our dog has slept under the bed since we moved to the new house - I was wondering what had caused the slight abnormalities..... 

No, that was just a side effect of visiting Hades.

Simon-in-Suffolk posted:

David Hendon posted:

Ofcom hasn't "moved off into other directions". It's a consequence of the single EU market. If the device conforms to the relevant harmonised European standard as regards the EMC Directive then Ofcom can not by law choose to ignore that. 

David - it is or was not as straightforward as that as there was debate and lack of consensus on which EMC Directive applied...and it really seemed to depend from what I saw which lobby group you formed part of...  the issue was that radio transmission from the attached mains wiring was an unintended consequence of PLA operation and this was the one of the key issues - and EMC compliance test results seemed to vary on the wiring used - and this is or was not standardised - i.e. there is not a Euro house.

Some of the EMC results i saw, of yes devices a few years old now, were quite shocking..

Simon

I don't disagree about the "was shocking" comment. But the position right now , especially as concerns what Ofcom thinks about it, is as I describe (speaking as an Ofcom person....)

best

David