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Anonymous
(Unregistered)Fri 18-Nov-11 19:54:10
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Reducing SNR target..any issues?


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My ADSL line has worked happily for years at around 3 Meg, and I really paid it no attention, as that does the job. Recently things slowed down noticeably and I was getting dropouts: a speedtest revealed a profile of 500kb, and investigation revealed a lot of line noise. To cut a long story short, I now have a new dropwire, new NTE5, ADSL faceplate filter, Cat-6 modem cable and a lot more knowledge, including the fact that I can get ADSL2+ at 4-6Mb. The main thing preventing such speeds seems to be a target SNR Margin of 12dB (was 15 when faulty). Being impatient, and having a DG834GT, I've endowed it with DGTeam firmware and tweaked the Noise Margin down to 8dB. Sync speed is now 4.7Mb, but I'll have to wait for the profile change of course (currently 3000). Finally, the question: Does this modem tweak affect what the BT kit will be trying to do? I understand it can take 14 days to adjust the SNR target. Thanks! (and if my margin stays nice and steady, how low should I risk going?)

Steve
Anonymous
(Unregistered)Fri 18-Nov-11 20:22:14
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Re: Reducing SNR target..any issues?


[re: Anonymous] [link to this post]
 
In reply to a post by Anonymous:
My ADSL line has worked happily for years at around 3 Meg, and I really paid it no attention, as that does the job. Recently things slowed down noticeably and I was getting dropouts: a speedtest revealed a profile of 500kb, and investigation revealed a lot of line noise. To cut a long story short, I now have a new dropwire, new NTE5, ADSL faceplate filter, Cat-6 modem cable and a lot more knowledge, including the fact that I can get ADSL2+ at 4-6Mb. The main thing preventing such speeds seems to be a target SNR Margin of 12dB (was 15 when faulty). Being impatient, and having a DG834GT, I've endowed it with DGTeam firmware and tweaked the Noise Margin down to 8dB. Sync speed is now 4.7Mb, but I'll have to wait for the profile change of course (currently 3000). Finally, the question: Does this modem tweak affect what the BT kit will be trying to do? I understand it can take 14 days to adjust the SNR target. Thanks! (and if my margin stays nice and steady, how low should I risk going?)
Steve
If with in the so called training period(10 days) it could have an adverse effect as bt subject their bb, to DLM and the stupid profiling system,
But as far as how much can you lower the snr,thats down to your line really,if it doesn't get subjected to any noise it could run happily on a 1db margin, it's a case of trial &error really
Standard User RobertoS
(sensei) Fri 18-Nov-11 23:43:38
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Re: Reducing SNR target..any issues?


[re: Anonymous] [link to this post]
 
The jury is out on that. I preferred not to tweak when waiting for the auto-drop, but people I trust to have it right tweaked and still got the drop.

What also happens sometimes is that the drop just doesn't materialise, but there are usually other factors at play then.

All you can do is stay tweaked for a fortnight I suggest, as re-sync's should be kept to an absolute minimum.

You are not in a 10-day training as that would have reset it anyway. In any case I believe the earlier anon poster is a victim of the widespread misinformation about that 10 days. The BT DLM runs from minute 1 for ever, and all the 10-day period does is record the lowest connection speed that occurs. There is no special tuning going on.

My broadband basic info/help site - www.robertos.me.uk
My domains,website and mail hosting - Tsohost. Internet connection - IDNet Home Starter Fibre. Live BQM.

"Where talent is a dwarf, self-esteem is a giant." - Jean-Antoine Petit-Senn.

Edited by RobertoS (Fri 18-Nov-11 23:45:09)


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Standard User b4dger
(knowledge is power) Sat 19-Nov-11 12:43:18
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Re: Reducing SNR target..any issues?


[re: Anonymous] [link to this post]
 
I would also be inclined not to tweak so that your error counts are lower in the hope that BT's DLM will see you have a clean line and reduce your TSNRM automatically.

NB. Another option would be to ask your provider to take some action.
Consumer Controlled SNR (CCSNR) should allow them to reset your target now your line has been sorted. This came in last year for ADSL2+ but you don't seem to hear much about it...

Anonymous
(Unregistered)Sat 19-Nov-11 20:30:43
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Re: Reducing SNR target..any issues?


[re: b4dger] [link to this post]
 
Thanks everyone for your feedback -- appreciated.
I set my tweak at ~12% to get the SNRM down to 8dB and got a useful increase in sync speed. The DLM seems to have done its stuff with some alacrity, as my profile has been increased this afternoon from 3000 to 5000, and the SNRM is now 4dB, so it looks as though both can work together (but if BT have another bite, I could be in to negative, and will have to reduce the tweak).
Having spent around 2 hours in total on the phone to Orange's broadband support in Mumbai I'm convinced that asking them to do anything is/was a complete waste of time. Polite but dim. Their 'voice' support people in Ireland are spot-on, and wasted no time in establishing that I had a line fault, but after that it was hopeless.
I learnt more in 30 mins on Kitz and TB than I would in a week on the phone to Orange.
Thanks again,
Steve
Standard User XRaySpeX
(eat-sleep-adslguide) Sat 19-Nov-11 22:41:37
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Re: Reducing SNR target..any issues?


[re: Anonymous] [link to this post]
 
Are you on 21CN ADSL2+ or 20CN ADSL(1)? What exchange? Post your router stats?

Orange phone support have no technical knowledge. Better to email them on their website. I did to get my Target NM down and eventually they reacted.

1999: Freeserve 48K Dial-Up => 2005: Wanadoo 1 Meg BB => 2007: Orange 2 Meg BB => 2008: Orange 8 Meg LLU => 2010: Orange 16 Meg LLU => 2011: Orange 17 Meg Untweaked 19 Meg Tweaked WBC
Anonymous
(Unregistered)Sat 19-Nov-11 23:43:52
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Re: Reducing SNR target..any issues?


[re: XRaySpeX] [link to this post]
 
I'm on Rhyl exchange. It's 21CN but I'm miles away. Attenuation was 51dB at 3000kbps but now at 5000 its 57. BT estimate for the line is 5-7Mb, Orange reckon 4-5.
emails to Customer Service just seem to get requests to phone their 'tech support'.
Anyhow, I seem to be squeezing out about as much as can be expected.
Currently syncing at 5800 and 3.8dB NM.

Cheers,
Steve
Standard User InQ
(member) Tue 22-Nov-11 12:43:43
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Re: Reducing SNR target..any issues?


[re: Anonymous] [link to this post]
 
The noise on your original line - could you hear it on the phone? If not how did you know there was noise?

Reason i ask is that my SNR Margin is currently 15dB, i've been in the property about 7 years and it started off at 6dB but has seemed to got worse over the years ( i was synced at 8128kbps then but now its more like 5000-6000kbps tops).
It was reset to a target of 6dB about a month ago but went up to 15dB over about 1-2 weeks.
I cant hear any noise when i make a normal phone call and i have a NTE5 filtered faceplate.
Anonymous
(Unregistered)Wed 23-Nov-11 00:37:11
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Re: Reducing SNR target..any issues?


[re: InQ] [link to this post]
 
I could hear a bit of noise, and callers had made a couple of remarks that our line wasn't great, but it hadn't ocurred to me that it was affecting broadband.
When I called tech support about poor speed and dropouts the guy in Mumbai said he thought the line was noisy, and recommended I call the voice support for Orange. I did, and they ran line tests which actually give some sort of result that confirmed the line was failing the tests (3 times).
At that point they will escalate to BT but they ask you first to make sure it isn't a fault in your wiring by repeating with a different phone plugged into the test socket and with everything else disconnected.

Steve
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