Kitz Forum
Broadband Related => Broadband Hardware => Topic started by: andyfitter on May 04, 2017, 07:34:32 PM
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The attached screen shots show the performance of my line over the last two days. Initially the power line adaptors are in use, then for a period today I stopped using them, and then around 6pm this evening I started using them again as a test.
Downstream significantly affected during the entire time the powerline is active.
Stats available as 'andyf' if anybody is interested.
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Thank you for posting those plots. The effect caused by such devices does not surprise me . . . :no:
In attempting to "get the message" across, I always suggest that the frequency band used by such devices is compared with that of the xDSL service.
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So why can't they be designed to use frequencies which do not interfere with xDSL ones?
Stuart
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Probably because mains wiring is even more unsuitable for high frequencies than telephone cables.
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Mine make no difference whatsoever, not to noise margin, or errors or anything. Maybe the interference is with the higher frequencies, so more of a problem for FTTC.
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Mine make no difference whatsoever, not to noise margin, or errors or anything. Maybe the interference is with the higher frequencies, so more of a problem for FTTC.
I've found this - when I had ADSL I saw no effect at all but on FTTC they do impact it, although I find it depends how close the adaptors are to the router, so it's noise generated over the air rather than via the mains. But I need to do more investigation to confirm this to be the case.
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I've found this - when I had ADSL I saw no effect at all but on FTTC they do impact it, although I find it depends how close the adaptors are to the router, so it's noise generated over the air rather than via the mains. But I need to do more investigation to confirm this to be the case.
Being still on ADSL, I don't get problems either, but I'm somewhat flummoxed by your mention of "noise generated over the air". How can that be? I didn't know other than that an Ethernet connection was needed between the router and the sending PLA.
Secondly what is near the router in feet, and are actually measuring direct or on Ethernet cable length?
I apologise for what may be is a naff post, knowing I'm not clever like many here!
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When you use Powerline Adaptors the mains wiring is used to carry the DSL signals between the two (or more) points. The mains wiring is untwisted and unscreened, so it will radiate interference through the air as well as conducting it through the wiring.
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Eric! I see, so the radiation is all around like the atmosphere, but then what has the distance PLA to router got to do with it?
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When you use Powerline Adaptors the mains wiring is used to carry the DSL signals between the two (or more) points. The mains wiring is untwisted and unscreened, so it will radiate interference through the air as well as conducting it through the wiring.
The units themselves also may well generate noise without going through the wiring at all - hence why the further away they are from the router, the less the effect may be seen.
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When you use Powerline Adaptors the mains wiring is used to carry the DSL signals between the two (or more) points. The mains wiring is untwisted and unscreened, so it will radiate interference through the air as well as conducting it through the wiring.
All powerline adapters that I've seen carry Ethernet rather than DSL, certainly that's what mine do. What I haven't been able to find out on a quick check, is what frequencies it uses.
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You're quite right of course, I worded my message badly.
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Some may well be better than others. I'm sure Tony said the BT ones he tried didn't create any noise he could see - which would make sense because BT should have done extensive testing.
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Can confirm the ones Tony suggested a while ago (BT 500s) cause CRCs on my line and a lot of FECs.
The only powerline adaptors that seem to cause little issue are some very old TP-LINK AV200 ones - shame they're quite slow and thus not really fast enough for FTTC.
I've ordered a mains conditioner to see if I can remove the noise that is being generated - I can't believe it's happening over the air because the powerline adaptors are not at all close to the router now (they are a good 50+ metres away).
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May sound pedantic, but has to be pointed out...
Issues caused by powerline adapters will be a combination of...
The spurious emmisions radiated from wiring that carries the traffic.
And
The coupling between the mains wiring that radiates the emissions, and the wiring that feeds the modem.
That coupling will be affected by various attributes of both the mains wiring and the phone line, proximity of these cables to one another, and relative signal strengths of the real vdsl signal vs the interference. I'm not sure why proximity of modem to anything in particular should be a factor, but who knows - it might.
That being the case, I'm not at all surprised that by simply monitoring observed error rates, some people have 'evidence' of catastrophic damage, while others see no detriment whatsoever. Too many variables. :)
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This is why I'm hoping a mains conditioner where the modem is might stop the noise from the mains?
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I would argue that any interference is most likely picked up by the telephone wiring before it reaches the modem. In that case a mains conditioner would make very little difference but I am certain this is an inexact science so who knows, try it, and if it works just be grateful.
Another thought ocurred to me earlier. Obviously, any imbalance in the phone wiring, such as a non-filtered ring wire, would mak matters worse. But what about imbalance in the mains wiring, would that make matters worse too? I'm not an electrician, but I'd speculate that mains imbalance might be worsened by some fault conditions, such as a break in just one conductor of a ring circuit.
Another factor might be the house earthing system. With many, but not all, domestic installations, I understand rhat the 'earth' is simply bound to nuetral in the meter cupboard. If earth is bonded to neutral then all earth bonding within the home, to water and heating pipes, kitchen sinks, etc, are in effect directly connected to neutral and, not sure, but maybe acting as a radiating antenna? The extent of earth bonding depends, I believe, on when the wiring was installed as regulations change in time. But might all that make a difference, presenting imbalance that worsens interference from power line adapters, but varies a lot from one home to another?
Stress again, I am not an electrician. And I am most certainly not suggesting anybody start checking out their own mains wiring, or earthing systems, very dangerous territory. But I would welcome discussion on these points, especially from anybody better qualified than me?
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In response to sevenlayermuddle, my experience in high power RF systems is that the RF performance of power wiring is a lottery.
I believe years ago the IEE set an exam calculation involving a 50 Hz power transmission line about 1500 Km long. Power engineers were puzzled to find more volts came out than went in, because they KNEW that was impossible ! RF engineers just said " Ah, quarter wave at 50 Hz OK".
This is the key point, power engineering ignores everything but 50 Hz so systems are not designed with any RF consideration. When it comes to not just transmission but possible interference, as far as I know only Radio Amateurs are, (certainly were) required to have any knowledge of the subject.
In other words using a power connection for information is a lottery; if it works consider yourself lucky. If not forget it don't whinge !
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Thanks for that, JGO.
One hypothetical scenario that concerns me, but doesn't seem discussed too often, is where some neighbouring household uses power line data, my phone line happens to pass their property, and the lottery conspires against... So my connection would be adversely affected, but difficult to prove the cause, and no comeback even if proven - since the devices have all required approvals.
Personally I think the very fact these devices might, in some common circumstances cause major problems, should be enough to have them banned. The accepted fact that they sometimes do not cause problems, at least to DSL connections, should be no excuse against the fact that they might.
If we can ban proper light bulbs, and ban powerful vacuum cleaners, and ban whatever else, why can't we just ban power line data - at least for domestic use? >:(
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Personally I think the very fact these devices might, in some common circumstances cause major problems, should be enough to have them banned. The accepted fact that they sometimes do not cause problems, at least to DSL connections, should be no excuse against the fact that they might.
What about banning cars or electricity supply which do cause injury or death ?
Unfortunately we have to use sense if we don't want to live in a nanny state.
Suggest decent power line filters would mitigate the case you suggest; the transfer is supposed to be conduction not radiation.
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The difference with an electricity supply, or driving a car, is there are a set of carefully considered rules that govern how the technology is used. The rules are set in statute and as long as the rules are followed, the risks are reduced to a level that has been deemed to be acceptable.
I am not convinced the same argument applies to Power Line Adapters. It seems to me that no matter what rules are followed it will be largely a lottery, whether or not they cause problems. And even if they do not cause a problem to the user's broadband, they may unkowingly affect somebody else's broadband, or somebody else's Radio reception.
But I see this issue has actually been done to death by Ofcom and even debated in parliament, plenty of requests to have them banned, with no agreement to do so. Most recent hits from a recent search suggest Ofcom were thinking about prosecuting the users of problematic devices, which seems a tad harsh, as 99% will have not the slightest concept what they've done wrong.
See from a couple years ago, not sure what came of it?
http://www.ispreview.co.uk/index.php/2015/01/ofcom-propose-prosecute-owners-bad-powerline-network-adapters.html
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You seem to be arguing that when something may cause interference it should be illegal, but not something which is known to be lethal ?
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No that is not what I was arguing at all.
Not sure how my words came across that way, but I'll refrain from trying to explain these points any further as I'm not even sure why we are discussing lethal dangers of electricity supply, and car accidents, in the context of power line adapters?
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I agree they should have been banned, but ofcom are past that point now, there is so mucb widespread use of the devices they wont be banned unless its determined at some point in the future they cause a health hazard.
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I agree they should have been banned, but ofcom are past that point now, there is so mucb widespread use of the devices they wont be banned unless its determined at some point in the future they cause a health hazard.
Or maybe spin a yarn that they contribute to global warming? ::)
Actually that may not be so far fetched. I don't know how much power they consume. It'll be tiny I'm sure, but since they will often be on 24/7, the energy saved by banning them might be comparable to other items banned in the name of climate change.
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Why mess about ? A fibre-optic data link is proof against most things short of an atomic bomb. I worked on one about 1960 and the 100kW transmitter from which the data was coming didn't bother it at all.
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Why mess about ? A fibre-optic data link is proof against most things short of an atomic bomb. I worked on one about 1960 and the 100kW transmitter from which the data was coming didn't bother it at all.
I'm impressed. :)
I started Uni in early 70s and when we first toured the engineering labs there were various fibre optic projects going on. First time I'd seen that technology in the flesh, all seemed very cutting-edge and futuristic, though istr the various projects were more about analogue transmission of voice/video, vs data?
We're verging off-topic mind, hope we don't get scolded. :-[
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Why mess about ? A fibre-optic data link is proof against most things short of an atomic bomb. I worked on one about 1960 and the 100kW transmitter from which the data was coming didn't bother it at all.
Not so fast...
The fusion joins in fibre optic are very susceptible to freezing conditions being the location where the fibre is exposed from its sheath.
Water gets into the joining enclosure, freezes and then crushes the fibre which totally messes up its transmission properties. Known problem in countries which get seriously cold.
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The fusion joins in fibre optic are very susceptible to freezing conditions being the location where the fibre is exposed from its sheath.
Water gets into the joining enclosure, freezes and then crushes the fibre which totally messes up its transmission properties.
OK but Powerline Adaptor wiring used in place of an Ethernet link would be indoors ? well mine would !! .