Dropping SNR, New Line or not?

Been having problems with my SNR dropping 3 to 5db as it gets darker after 4pm, always returns to normal by around 7am, this started about 1 year ago. I'm currently with Enta via UKFSN and twice last year after multiple reconnects and a jump to 12db they got BT to reduce my SNR back to 6db, I changed routers to a 585v6 but lost routing below 4db, changed again to Netgear DG834GT which rests itself and now gone back to a 2Wire 2700HGV which will keep sync and routing no problem at all.

Current problems started when Enta switched to ISPC and my speeds dropped to 50k at some points, multiple support requests to Enta led to BT doing deep diagnostics and causing several resyncs within a couple of minutes which pushed my SNR up to 15db, this was a 3 weeks ago and it's still there, Enta say they can/will not ask BT to reset it and the line still drops 3-5db.

So, question is this, if I get a second line installed how likely is it to suffer the same problems?, my neighbours router is solid at 6db (even tried using his Netgear router on my line with same problem) so I assume my problem is with the cable from the pole to my house?. If I call BT out to check my line it's £120, a new line would be £170 and if that would cure the problem I would do that then cancel the original line.

Edited by jeff1106uk (Sun 08-Mar-09 13:20:28)

SNR problems after dark are usually caused by wiring acting as an aerial for radio signals. Do you have any extensions coming off the master socket, or do you have a long extension wire feeding the router ?

Could be something creating noise in your property, in which case a different line would not help

Been through everything in the house over the last year, unplugged every electrical item, changed central heating times etc.,completely removed the phone extension lead and put the router downstairs next to the phone socket, plugged directly into test socket.

Normal connection to 3 PCs which are all upstairs is via 15m of Cat5E to a 4 way switch, even with that removed and using a wireless connection on the laptop the drop is still present so I think that pretty much rules out internal wiring etc.

Does your phone line enter your house overground (via a pole) or underground ?

If radio pickup isn't the problem, it might just be that you're on a pair in a trunk cable surrounded by other pairs which are all on broadband, and who all turn on their routers after 4PM (when the kids are out of school). Does the problem change timing when the days get longer ? Or is is always about 4PM ?

It's an overhead feed, it seems to be when it starts to get dark not a fixed time, 4pm or so at the moment.

Started dropping from 15db gradually at 16:45 yesterday, hovered between 9 and 10db from about 8pm then bouncing between 8 and 10db from 10pm until 05:00 when it started rising again back to 15db by 08:00. So a variation of 7db over 16 hours, there have been days where it's only varied by about 4db though. May be worth noting that it was very windy last night.

During the day Routerstats shows a perfect flat line, no variations at all until the fun starts again at tea time.

Edited by jeff1106uk (Mon 09-Mar-09 13:52:16)

My longish (50db) rural line, also overhead behaves in a similar way.
The SNRM reducing as darkness falls is fairly normal I'm afraid (AM rf and the ionosphere and other stuff I don't understand).

I've tried numerous routers and found the Speedtouch 585v6 to perform best for my line conditions - see the link in my signature for details.

If you've done all you can for your line - filtered faceplate, tested using the TEST socket, etc. then trying different routers/chipsets is definitely worth a go (and just about all you can do!).

Yes, tried the 585v6 with mixed results, as BT/Enta have mucked about with my connection forcing the SNR up to 15db I was running the 585 with 6143 firmware and DMT to get it back to 9db, problem was the 585 wouldn't let me connect anywhere after the SNR dropped to 4db or below, didn't drop connection just wouldn't connect anywhere!. So now I'm back to the 2Wire2700 and waiting for the SNR to drop due to continuous connection, as it's only been connected for 7 days that may take a while!

So, assuming it is my bit of 20year old BT cable causing the problem would a new line with shiny new cable suffer the same problem?, I've fitted my 585 to a friends line in the next street, 6db with an 8M sync on fastpath, will check it tonight after mine drops again, she's not happy, 8M sync on Max with Tiscali and getting 1Mb speeds!, of course she can't run a BTSpeedtest as it's redirected elsewhere by (I assume) Tiscalis Datastream kit in the exchange.

Edited by jeff1106uk (Mon 09-Mar-09 14:42:27)

I'm using 6.2.29.2 version firmware - I believe others have reported similar issues when running your level of f/w.

In answer to your question - yes, changing your line to a shiny new bit of copper 'could' improve things - especially if it removes any old joins etc. in the process - trouble is getting BT to do this if there isn't a line fault could be hard.

Forking out for a new line/connection 'could' work but I guess they might just use an existing pair in your current line - or things could work out just the same or worse.
But yes, this is something I would try as a last resort - it all depends how essential you connection is. I work from home so it's VERY important to me.

Of course a 'tree branch' or something could easily cut through the line as it's quite windy today...


EDIT: I wouldn't try tweaking your Target SNR at this point - I would just aim at getting a stable and reasonably error free connection to begin with.

Edited by b4dger (Mon 09-Mar-09 15:00:49)

> would a new line with shiny new cable suffer the same problem?

It won't be a shiny new cable though. It will be a spare pair in existing cables - quite likely the exact same ones your current line uses although that isn't certain - it could easily be worse if they have to take you on a guided tour to bypass full cable sections anywhere.