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Warning about powerline adapters

bogmonster
Newbie
Posts: 7
Registered: ‎06-01-2015

Warning about powerline adapters

Hi,
I just want to let you know my experience with powerline adapters. The ones I am was using were Netgear 500AV homeplug ones. I have been trying to improve my ADSL line and have been using DSLstats. I had noticed that my SNR dropped rapidly at certain points so I went around the house unplugging everything trying to find the source. It took me a couple of hours to work it out. The problem is with the powerline adapters. What was tricky is that they appeared fine just idling along and transmitting my feeble 2.5Mbps 'broadband'. Anyway, it took me a while to realise that as the bandwidth through the adapters went up they caused significant and very clearly defined drop in SNR of about 1.5dB. Given that I am on a long line this is enough to cause significant grief.
I have read lots of people saying they have had no issues with these and a few saying they have. Apparently it tends to be worse if your house has overhead power cables that come in close to the telephone cable as my house does.
Anyway, I will not be using them again. Of course you may get different mileage so I am not saying don't use them, just be aware that they may cause issues in some circumstances and possibly for your neighbours as well.
One other interesting observation was that I also had a very marked increase in SNR for a 10 minute slot. I don't think that was anything to do with me so I suspect that could be caused by some external interference being removed. Apparently the powerline signal can travel some distance through the mains supply so maybe my neighbours are also using powerline adapters?
Regards, BM
16 REPLIES
Superuser
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Registered: ‎22-08-2007

Re: Warning about powerline adapters

As with all technology. it all depends on how well they are made.  Switch Mode Power Supplies are notorious for generating REIN.
There are a number of us around here using powerline adapters from other manufacturers without issue.
Community Veteran
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Re: Warning about powerline adapters

Community Veteran
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Registered: ‎31-08-2007

Re: Warning about powerline adapters

A well known long standing issue I'm afraid and it's not just the power supplies within them.
With regard to your previous thread about interference bogmonster, I've made this post http://community.plus.net/forum/index.php/topic,135662.msg1190135.html#msg1190135 primarily because of the ridiculous suggestion in the preceding post to use homeplugs!  I hope when the Openreach engineer comes you can at least get the master socket resolved along the lines that I've posted. If you have any further queries about your wiring or interference, post on that thread and we should be able to provide some more help.
Kremmen
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Registered: ‎13-04-2013

Re: Warning about powerline adapters

Can I get clarification of the HomePlug warning.
I'm using HomePlugs perfectly OK from my router to an upstairs PC. Is the warning relating to using HomePlugs as the main route to the router or HomePlugs in general?
Let's be careful out there !
Community Veteran
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Registered: ‎10-06-2010

Re: Warning about powerline adapters

The amount of interference that gets picked up from your mains wiring by your telephone wiring will depend on a lot of things, such as how close your mains wires are to your telephone wiring, the quality of the telephone cabling, if mains and telephone wires run in parallel with each other for any significant length (which they probably shouldn't), and the amount of telephone wiring the xDSL signal is on. If you have a centralised filtered faceplate on your master socket, the filter should block the vast majority of any interference picked by any extension wiring.
This thread also reminded me of this blog post about picking up your neighbour's powerline signal.
Community Veteran
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Re: Warning about powerline adapters

The type of filtering is largely irrelevant. If the particular homeplugs are chucking out interference it can get into the system anywhere and as has been mentioned elsewhere it could have a greater effect on FTTC installations.
Community Veteran
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Registered: ‎27-05-2011

Re: Warning about powerline adapters

It's all down to personal preference IMHO  Smiley
We recently had fibre installed
With due deference to SWMBO I have neatness built in to my arrangement. I installed a double power socket near the master socket and now have a all my telecoms in one corner near the front door. This includes OR modem, PN router, LightwaveRF link, cordless phone base station. The rest are connected through a Solwise piggy unit which as well as being a homeplug acts as a filter for the switch mode power supplies
This homeplug feeds three other homeplugs for desktop, smart television and through a four way - blueray, rasberrypi and sky box.
We sync at a rock solid 30Mbps and download at 28 near the router. So the connection doesn't seem impacted significantly  Smiley
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Community Veteran
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Re: Warning about powerline adapters

Peter, it's not personal preference. There are a lot of these homeplugs that chuck out buckets of interference. It all depends on the brand and the model. The specs. for these devices are grossly inadequate and Radio Amateurs in particular have been complaining about them for years!
Some are "lucky" in that they have no problem or the impact on their service is minimal, it doesn't mean that the next door neighbour isn't suffering from them though Shocked
bogmonster
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Registered: ‎06-01-2015

Re: Warning about powerline adapters

Ops, started something  Embarrassed  That wasn't the intention....
I don't have a particular axe to grind here. I decided to try them because they were very cheap (on sale at PC World) and easy to try without difficult ethernet cable runs in the house. I was aware they might cause an issue but missed it completely at first because the issue only showed up when transferring reasonable amounts of data. I took a punt and it din't work out well for me. As I said, other people may get on fine with them. I am going to return them to the shop so all I have lost is a couple of hours messing about.
I can't provide an adequate explanation of why it impacted me and not some others because I don't have the expertise. I suspect some combination of the model of adapters and my house wiring and the very long telephone line I have. Out of curiosity I tried another brand that a friend had kicking about and these had a very similar result.
What I do know is that in my circumstance there was a definite issue and that it would have been very difficult to track down without a router supporting DSLstats or similar. I found it because I was looking for it and was slightly dubious of the adapters from the start and because of Anotherone's words of caution.
I do have some sympathy for other people who are trying to use the radio spectrum legitimately if it is impacted by these devices and judging by my own experiences and some reading I have been doing I have decided that I am not going to use them. Of course people will need to weigh up the information and make their own choice and I respect their decision and in turn I would hope they respect mine. And just in case anybody is wondering, I am not a radio amateur and I don't work for GCHQ  Tongue
BW, BM.
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Re: Warning about powerline adapters

And I on my part don't know how I have avoided problems seen by others.
@bogmonster you will find if you do a search on these fora many threads discussing this subject
I would have argued that I was using homeplugs from a reputable supplier and not Chinese knockoffs but you got yours from PC World so they would best quality meeting all applicable specs - wouldn't they?  Huh Roll eyes Smiley
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Superuser
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Re: Warning about powerline adapters

Peter,
I can not tell if you said that with a straight face or a tongue firmly planted in your right cheek!  PC World and best specification are not two thoughts I would naturally conjoin.
You are though right that there is a high degree of variability on the quality of these products, similar to cheap Chinese SM-PSUs I expect that similarly cheap Chinese HPs will suffer the same issues.
I use Devolo HPs (they are anything but cheap) and have not been aware that they have caused issues.  I do though use RS 24x7 (even when I do not have a specific issue) and from time to time I see 0.5dB SNRM shifts which I have never been able to correlate with anything within the home... next time I see such a step I will go and turn off the HPs and see if they are the culprits!
Kevin
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Re: Warning about powerline adapters

You might want to read the last page of Test Report - VDSL2 and in-door PLT coexistence.
Kremmen
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Re: Warning about powerline adapters

Not an easy read but the findings seem to indicate use top quality cables of at least cat5?
Let's be careful out there !
Community Veteran
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Re: Warning about powerline adapters

Using cables full stop. That's the best cure!
The brand is largely irrelevant, price is irrelevant. Chinese copies are likely to be considerably worse. As mentioned previously, the specifications for these devices are inadequate as EMC is not properly addressed.
Further reading (BT Vision even get a mention)  -
http://stakeholders.ofcom.org.uk/enforcement/spectrum-enforcement/plt/
https://ico.org.uk/media/action-weve-taken/decision-notices/2011/587440/fs_50301488.pdf and
http://www.ban-plt.org.uk/
just a few places that have information.