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ADSL2+ - crazy noise margin values

cjags
Rising Star
Posts: 443
Thanks: 10
Fixes: 1
Registered: 31-08-2007

ADSL2+ - crazy noise margin values

I have been having ongoing problems with the connection since going to ADSL2+.  There is a ticket number 52327238 but thought I would post here as well in case others have any ideas.
What happens is after a few days of connecting nicely with the noise margin at around 6db, at about 7am, the BT exchange and my modem decide that they can go a bit faster.  The noise margin drops to 3db and the connection speed goes up but now, the modem cannot log in to Plusnet so the interent connection drops even though the modem still has DSL sync with the exchange.
Then the exchange and modem decide to go even faster.  The noise margin drops to 1db and the connection speed goes higher.  The noise margin fluctuates a lot between -2db and 1db.  The whole thing has to fixed with a modem reboot.
Plusnet have made changes to keep the target noise margin 6db (and even 9db) but they don't seem to be permanent.
Problem happens with different modems and also in the BT test socket.  Does anyone else have similar problems?
38 REPLIES
jojopillo
Grafter
Posts: 9,786
Registered: 16-06-2010

Re: ADSL2+ - crazy noise margin values

Hi cjags,
I've set the target to 6dB. It can take 24 hours to take effect though.
Jojo Smiley
cjags
Rising Star
Posts: 443
Thanks: 10
Fixes: 1
Registered: 31-08-2007

Re: ADSL2+ - crazy noise margin values

Many thanks. Look forward to it kicking in.  Currently still between 0db and 3db Sad
cjags
Rising Star
Posts: 443
Thanks: 10
Fixes: 1
Registered: 31-08-2007

Re: ADSL2+ - crazy noise margin values

Has spent all of today around 3db and in the last half hour, dropped to 0db Sad
Had to reboot.
Now back to 3db.
When will the 6db target kick in?
Plusnet Help Team
Plusnet Help Team
Posts: 13,487
Thanks: 248
Fixes: 68
Registered: 27-04-2007

Re: ADSL2+ - crazy noise margin values

TBH I'd have expected that to take effect by now, I'll submit that again for you now.
Adam
If this post resolved your issue please click the 'This fixed my problem' button
 Adam Walker
 Plusnet Help Team
cjags
Rising Star
Posts: 443
Thanks: 10
Fixes: 1
Registered: 31-08-2007

Re: ADSL2+ - crazy noise margin values

Many thanks.
Checking the router logs, it was 6db early this morning but decided 3db was better for the afternoon.  Undecided
Currently sat at 1db  Shocked
Plusnet Alumni (retired) orbrey
Plusnet Alumni (retired)
Posts: 10,540
Registered: 18-07-2007

Re: ADSL2+ - crazy noise margin values

Hi cjags,
Looks like it's at 4dB at the moment, hoping that things are improving for you?
cjags
Rising Star
Posts: 443
Thanks: 10
Fixes: 1
Registered: 31-08-2007

Re: ADSL2+ - crazy noise margin values

The support team have done some line tests and have recommend my circuit is put on the DLM trial to ensure SNR margin stays above 6db.
Fingers crossed.
While I am impressed that the circuit can work at higher speeds with a noise margin of 3db and lower, it just isn't reliable enough so I am more than happy to stick at 6db and sacrifice a bit more speed for a stable connection.
[Edit]
Support have just posted ths on my ticket
"Unable to increase SNR as still in stabilisation period until tomorrow."
Perhaps why JoJo and Adam's changes failed to work?
Plusnet Help Team
Plusnet Help Team
Posts: 13,487
Thanks: 248
Fixes: 68
Registered: 27-04-2007

Re: ADSL2+ - crazy noise margin values

Quote
Perhaps why JoJo and Adam's changes failed to work?

That shouldn't stop an SNR reset from going through TBH, sometimes they do fail unfortunately and we have to reattempt them.
If this post resolved your issue please click the 'This fixed my problem' button
 Adam Walker
 Plusnet Help Team
cjags
Rising Star
Posts: 443
Thanks: 10
Fixes: 1
Registered: 31-08-2007

Re: ADSL2+ - crazy noise margin values

Looking good.  9db all day and 6db this evening Cheesy
Plusnet Alumni (retired) orbrey
Plusnet Alumni (retired)
Posts: 10,540
Registered: 18-07-2007

Re: ADSL2+ - crazy noise margin values

Hi cjags,
Noted the comments on your ticket, was there a blip over the weekend? Looks like things are better now, your downstream SNR is up to 7.2dB and looks healthy, and the latest connection is over 17 hours long - hope it stays that way for you.
mojorisin
Grafter
Posts: 111
Registered: 31-07-2007

Re: ADSL2+ - crazy noise margin values

This seems to be the same for me since moving to ADSL2+ goes from 6db to 0db usually sitting about 3db great synch speed for my line length but connection is too flaky like this
cjags
Rising Star
Posts: 443
Thanks: 10
Fixes: 1
Registered: 31-08-2007

Re: ADSL2+ - crazy noise margin values

update:  Connection has been pretty stable all week with noise margin between 3db and 9db (the odd dip to 1db but no loss of connection) and a steady connection speed of 10M.  Fingers crossed all is sorted and the settings don't get reset. Smiley
cjags
Rising Star
Posts: 443
Thanks: 10
Fixes: 1
Registered: 31-08-2007

Re: ADSL2+ - crazy noise margin values

Looks like something has been reset somewhere and the target SNR of 6db has been lost.
Community Veteran
Posts: 19,101
Thanks: 443
Fixes: 21
Registered: 31-08-2007

Re: ADSL2+ - crazy noise margin values

You've got some horrible spikes of noise there, do the timings of them coincide with any electrical equipment switching on/off at your end?