FTTC / PowerLine Ethernet - A Warning!

[#1]

Hi All,
Here is my warning/tail of woe, over the use of HomePlugs (powerline ethernet) with FTTC.
I had a very good sync (74Mbps) on my FTTC which over time plummeted. Eventually Interleaving was applied to the line, and my FEC/HEC errors started going through the roof. PlusNet/Openreach tried all sorts of things and could not fix the speed for more than a couple of weeks before it would drop like a stone, and errors would take over.
Eventually, through a lot of trial and error, I discovered that the HomePlugs (PowerLine Ethernet) work on/put out interference on the same frequencies that VDSL uses. Immediately after unplugging and re-syncing I gained 2Mbps. 3 days later, my line re-synced overnight back to 74Mbps, and interleaving was turned off.
Hopefully this may help those of you who are seeing similar problems. Of interest, I was using reasonably expensive Devolo homeplugs - not cheap ebay ones...
Good Luck!
James

[#2]

That's interesting. I use Devolo myself, a mix of various speeds bought over about 3 years (5 on the system total, 2 with WiFi). I have found them very useful, they cost about 1.5-2Mbps compared to straight wired but bring convenience.
I have been noticing the odd burst of CRC Errors Downstream (but None up) which I wondered if might be connected (excuse pun!) to home plugs? Thinking through as I type, I think the clue is in the Errors Down but None Up, Errors created by Home plugs would be perhaps opposite, or both?

[#3]

Mine was entirely downstream - with no errors on the upstream. My upstream sync stayed firm at 20000 all the time the downstream was dropping, and was never placed into interleave.
James

[#4]

Could the same apply to the BT home plugs some of us are using?

[#5]

SlinkyWizard,
Do you know how the interference was getting into the modem, was it from the modems mains power adapter, or via RJ45 port?
I run TP-Link power line adapters and suspected interference could reduce modem speeds.  Because of this I run my modem / router via a mains conditioner, see link below.  I can confirm these reduce the signal from my power line adapters, however they don't completely eliminate the signal.
http://www.amazon.co.uk/LINDY-Mains-Conditioner-Power-Strip/dp/B00289GSC0/ref=sr_1_2?ie=UTF8&qid=143...
I'm planning on hard wiring my house with RJ45 cable, but it's one of those jobs I keep putting off.

[#6]

I'm thinking it was RF interference, as all my kit is behind a UPS so that will be filtering the mains for the router. All the HAM radio guys complain massively about PLE as well because it interferes with their radios.
BT Home Plugs would potentially cause the same problem.

[#7]

Quote from: stoswald

Could the same apply to the BT home plugs some of us are using?

Yes - I have seen similar problems to the OP with BT home plugs before.    Most people seem to use them (along with other models) without any issues at all though - given that I suspect the problems are caused by the frequencies in use for the line or the house wiring (or a combination of both).
I tried using RF chokes on the cables out of interest at the time but it did not make any difference in my case - in the end I just ran a long length of cat6.

[#8]

Quote from: SlinkyWizard

I'm thinking it was RF interference, as all my kit is behind a UPS so that will be filtering the mains for the router. All the HAM radio guys complain massively about PLE as well because it interferes with their radios.

RF now that's something I never thought of.   I do however use a 0.5m twisted pair RJ11 to the modem.
http://www.tandyonline.co.uk/high-speed-rj11-dsl-cable-0-5m.html
How far was the modem from the power line adapter?

[#9]

On the advice here, I have removed my BT Home Plugs, boxed them and will put them out of site.  I ran a 10m cable from the router to the smart blue ray and found that Netflix did not drop its connection and appeared to load quicker than via the home plugs.

[#10]

I had exactly the same issue. It was only when I switched to a Huawei modem (because of the G.Inp issue) and unlocked it, could I see the huge amount of errors on the line.
Through trial and error, I traced it to the powerline networking adapters, which are now reboxed and back in the loft.
As a general note, one of the best things I did was gain access to my line stats (through the unlocked Huawei modem). Having access to so much information can help you diagnose a lot about your connection.
Without the stats, you are virtually working blind.
A useful stat to look at when diagnosing such issues (like powerline adapter noise), is to monitor the FEC graph, and see how the errors drop as you switch things off.

[#11]

Just wondering: how close is the modem to the homeplug, were they sharing a power socket? I'd guess that just putting a little distance between them could help.

[#12]

I'm using TP-Link homeplugs, one of which is plugged in about a foot away from the modem and am having no issues at all! Wonder why some are affected but not others.

[#13]

Does any part of your BT line run near the mains circuit?  I have a theory the frequency the powerline is putting on the mains line is jumping over to the BT line, similar to cross talk on 2 or more BT lines running next to each other.  If your BT line is well away from mains circuit then it could explain why your not effected.
adie:quote

[#14]

My BT line was right next to the double socket that the homeplug was connected to. Where the cables ran once inside the wall I cannot say though!
The homeplug was on it's own socket, with the UPS running the equipment rack on another socket.

[#15]

Quote

If your BT line is well away from mains circuit then it could explain why your not effected.

My phone socket is about halfway up the wall well away from power lines. Explains that then!