Neighbour gets 2x bandwidth

[#1]

zyxel's are excellent runners on long lines, my zyxel is on a 63+db line and currently running at 1792 kbps @ 9db , use to be 6db NM running @ 2016 kbps which was enough to get a 1750 profile.
tho my NM has some how upped to 9db durring a thunder storm a few days ago even after running since march at what looked like a fixed NM offset.

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Personally, I like the Netgear DG834Gv4, as it is very stable on long distance lines.  Can be picked up very cheap on e-bay.  I hear the 'GT version is good too.

my netgear dg834g v4 on this line is complete rubbish even at the same NM as the zeyxel it syncs a good 500kbps lower. tho on my old 50db atten line it was a good stable runner, but now my family have taken over the line they run the thompson on interleaved and have got a 4500 kbps profile where i ran fastpath and was stable at 3000
could be worth doing what i saw a another customer do and buy a router off ebay see what it sync's like if its rubbish put it back on ebay and try another.
What router does your neighbor have?

[#2]

IME the best router for long/poor lines is the 2-wire 2700HGV (AKA BT Business Hub).  Zyxel are good too.  My netgear DG834GT is definitely third.
If you haven't already check your internal wiring as there may be a problem there.

[#3]

I'd try picking up and ex-Sky DG834GT on ebay and reflashing it with the DGTeam (http://dgteam.ilbello.com/) firmware. I've had good experiences with one of these on my frequently dodgy line, and the firmware  allows you to tinker with the target SNR at sync and retain those settings after a reboot (although this won't be much use if you have a banded profile). I've reflashed back and forth a few times to the default firmware without issue, but at least if you do brick it, you won't have lost much money.
If you don't mind leaving your PC on all the time for a few days, it might be worth downloading a copy of Routerstats http://www.vwlowen.co.uk/internet/files.htm, which might give you a clearer idea of what your SNR is up to with regard to fluctuations that might cause the drops. It will record just about everything else as well, but works best with Netgear routers. You can also use it to set the target SNR as with the DGteam firmware, but the settings will not persist between after a reboot.

[#4]

Well - it's on order and will try not to brick this one!  Still no response from the ticket I raised, so might be fiddling with SNR myself.  Will still have to have PN raise their cap though as I understand it.  Changing the target SNR from the router triggers BT to recalc the IP Profile I believe, so I'll presumably be aiming for an increased sync speed and then get PN to increase the cap and hey presto, I'll have double the bandwidth at the same level of reliability (i.e. my SNR margin will drop, but not too low as to drop syncs).

[#5]

IMHO tweaking the target noise margin should be absolutely the last resort.  It can't think it would have any magic effect on your IP profile and it could cause your connection to be unstable.  For me lowering the target margin using the dgteam firmware only has a marginal effect (because the netgear router normally connects at a slower speed than other routers).  Using a 2-wire router on the real target margin is no slower.
Your IP profile will eventually recover, although it can take some time  and the PN profile will follow shortly after.

[#6]

Hmm - first response on my support ticket has come through.
"... your signal to noise ratio (SNR) is currently set quite high which generally indicates that something would be pushing it up like that"
Again no clearer on which way round SNR Margin is!  Support engineer thinks that it being high is a bad thing and that must mean induced interference.  At the time of his test downstream SNR = 15, Atten = 52.5.  Is it the case that the margin is high, because there is variable noise on the line, so the margin must be kept up high to cope with it?  So what my router reports is a high margin generally, but that's because noise ratio was jumping around at the time of training (BP's SNR target being set).  Think that's the only way it makes sense to me.  In which case, I guess the best course of action would be to remove extensions and then get it retrained - the target SNR that is.  Ultimately, need to stop the extensions causing the noise, if indeed they are.  Presumably that requires synchronised action between me and PN so I can make sure they are disconnected when the SNR target is recalibrated?
My maximum stable rate was determined at 2272kbps, so why is my line rate set at 1250?

[#7]

I suppose, for doing that, can anyone comment on whether it is likely that extensions off the phone line filter in the master socket could induce sufficient noise in the router, plugged into the other side of the master socket?  I.e. wouldn't any noise in the ADSL spectrum be filtered out implicitly?

[#8]

Hi swinfen,
[quote=swinfen @ 11.19]
In which case, I guess the best course of action would be to remove extensions and then get it retrained - the target SNR that is.  Ultimately, need to stop the extensions causing the noise, if indeed they are.  Presumably that requires synchronised action between me and PN so I can make sure they are disconnected when the SNR target is recalibrated?
If you want to do this I would be happy to reset it for you.

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My maximum stable rate was determined at 2272kbps, so why is my line rate set at 1250?

At the moment the sync rate is 1504, which is in keeping with the 1250 profile
Jojo

[#9]

Hi swinfen,
Sorry in advance for being dumb ( I do have blonde streaks!)
Do you mean an extension from the phone socket on the microfilter, or  the extensions hardwired into the back of the faceplate?
Jojo

[#10]

I suspect you know much more about this than me, Jojo!  I have a dual port master socket - so my router is plugged into the ADSL filtered port and the extensions wired to the phone line filter on the face plate.  At least that is my understanding.  Means I don't need microfilters on every extension - as the BT engineer described it to me on installation, which makes sense.
So I guess it is still possible that noise can be induced on the extension lines (quite lengthy), but just that I would have thought it would be filtered out of the ADSL frequency spectrum as the extensions are downstream of the phone line filter.

[#11]

Hi swinfen,
with the faceplate you are describing, the front plate is hard wired and then filtered. The plug which is connected to the test socket will deliver the signal to your extensions, so by unplugging this you will cut out any noise they may cause.
Jojo

[#12]

Yep - well, if it is possible that the extensions can induce noise, I would like to eliminate that, but a tertiary test of plugging the router into the test socket indicated an identical SNR margin.  Doesn't prove that the margin will remain stable of course, and I don't doubt it seems possible that the extensions could be affecting it enough to result in my low stable SNR level during calibration.
Obviously, I would like to keep the extensions in the house!  I don't have many (lots on DECT), but the furthest is quite far away, so to design a system that minimises noise, but doesn't require a refit of my house would be preferable!
I wonder if there is a solution that electrically isolates the extension wiring to eliminate any potential for noise induction - like optical isolation?
Anyone got any suggestions?  Pretty sure I removed the bell wire, but if not that'll be the first thing I do.  Just never considered this an issue for my configuration, just for those who don't have their phone extensions pre-filtered.

[#13]

Hi swinfen
Not sure about electro/optical isolation techniques, lol
Could you isolate the extensions and give me a shout so I can run a line test?
Jojo

[#14]

Hi Jojo,
Will do - but when I get home.  Are you working late?!

[#15]

Hi swinfen,
No, officially until 5.30 but I can do it from home later for you. I'll give you a shout sometime after 7.30 if you like?
Jojo