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    Snr?

    This is a discussion on Snr? within the Sky Broadband help forums, part of the Sky Broadband help and support category; Hi, Just had D/E side changes made on my line. Before ADSL Link Downstream Upstream Connection Speed 10203 kbps 1022 ...

    1. #1
      hyeung's Avatar
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      Snr?

      Hi,

      Just had D/E side changes made on my line.

      Before
      ADSL Link Downstream Upstream
      Connection Speed 10203 kbps 1022 kbps
      Line Attenuation 32 db 18 db
      Noise Margin 14 db 9 db

      After
      ADSL Link Downstream Upstream
      Connection Speed 6979 kbps 765 kbps
      Line Attenuation 32 db 17 db
      Noise Margin 7 db 12 db

      My question is regards to the lowered SNR from 14 to 7db.
      Does this mean that the line i'm now on is poorer in performance?
      Or do i require to give it time for the exchange to adjust the SNR figure before i can resync back to the original speeds......?


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    3. #2
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      Re: Snr?

      If you have one I would try connecting to the test socket, link for details below in sig, then post stats back on here.

    4. #3
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      Re: Snr?

      Just had D/E side changes made on my line.
      Get back on to them, your connection is now far worse than it was before

      TomD


      Please note the views and recommendations in my posts are my own and in no way reflect the views of SkyUser.


      Useful Utilites

      http://www.nirsoft.net/utils/wifi_information_view.html/ TCPOptimiser /Test Socket

      Note - When downloading always select the Custom install or you will end up with stuff you don't want.





    5. #4
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      Re: Snr?

      another bodge job

    6. #5
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      Re: Snr?

      Think things are ok.
      After several hours waiting, my SNR nipped back to the same level.
      I did a reboot and the connection is now resynced at 10Meg

      ADSL Link Downstream Upstream
      Connection Speed 10234 kbps 765 kbps
      Line Attenuation 32 db 17 db
      Noise Margin 15 db 12 db

      Btw, you'll notice the upstream is lower.....thats because Sky capped this down.

      I still can't explain why my SNR wouldnt go back to 14-15db right away?
      Everytime i get a massive drop in SNR (negative) it causes a potential dropout.....then it tries to resync a couple of times at 10Meg, fails ofcourse and then resyncs at a lower speed. Consequently the SNR also shoots down i.e. 7db.

      So i have to wait several hours later for the SNR to return back to its normal levels....and only then will i be able to resync back to my original speeds.


      Can anyone here explain whats the score with regards to the SNR? Why do i have to wait for a period of time.....I've asked Sky, I've asked BT and no one seems to know?
      Is this normal?

      Is it because the router has tried to resync several times and failed....causing it to detect some weird fault and hence lowering both the speed and SNR?

    7. #6
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      Re: Snr?

      I think they have realized something was wrong and swapped you again. They can see more than you can looking from their end and would know it was not right.
      You are now capped at 10Mb so will not sync higher until they lift the cap. They will probably want to see if the line remains stable at that speed before the raise the cap a bit. The way your line was performing they will want to see if it stays stable through 24 hours. If it stays stable the cap could be lifted gradually. If I were in their position I would not want to take it off right away or you might be back where you started.

      TomD


      Please note the views and recommendations in my posts are my own and in no way reflect the views of SkyUser.


      Useful Utilites

      http://www.nirsoft.net/utils/wifi_information_view.html/ TCPOptimiser /Test Socket

      Note - When downloading always select the Custom install or you will end up with stuff you don't want.





    8. #7
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      Re: Snr?

      Quote Originally Posted by Isitme View Post
      I think they have realized something was wrong and swapped you again. They can see more than you can looking from their end and would know it was not right.
      You are now capped at 10Mb so will not sync higher until they lift the cap. They will probably want to see if the line remains stable at that speed before the raise the cap a bit. The way your line was performing they will want to see if it stays stable through 24 hours. If it stays stable the cap could be lifted gradually. If I were in their position I would not want to take it off right away or you might be back where you started.
      Still don't answer my question......?
      My connection appears to go into this weird locked down profile (lower speeds and lower SNR). Its only after a period of a few hours does it go back to normal?
      Ofcourse this only happens when i get this massive SNR drop issue.

      I've asked BT Engineers; I've asked Sky.....and No one seems to be able to give me an answer as to why this is?

      Someone must know if this is normal behaviour...and why its doing this?

    9. #8
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      Re: Snr?

      I've asked BT Engineers; I've asked Sky.....and No one seems to be able to give me an answer as to why this is?

      Someone must know if this is normal behaviour...and why its doing this?
      It is normal for the noise on any line to change over a period. That is why you have a noise margin, it is supposed to compensate for changes on the line. For some reason, your line has a very big swing in the noise present on the line, too big for the normal noise margin to compensate. This can only be caused by a fault somewhere, no matter what BTO or Sky may say. They seem to have done everything possible to trace or cure the fault, to little effect. If you are not happy with what you have now, your only solution may be to go to another ISP and hope they can give a better result. The problem is if this is an inherent line fault, then it does not matter what ISP you go to, it is still going to be there.

      TomD


      Please note the views and recommendations in my posts are my own and in no way reflect the views of SkyUser.


      Useful Utilites

      http://www.nirsoft.net/utils/wifi_information_view.html/ TCPOptimiser /Test Socket

      Note - When downloading always select the Custom install or you will end up with stuff you don't want.





    10. #9
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      Re: Snr?

      your line might be in DLM dynamic line manager

      DYNAMIC LINE MANAGEMENT (DLM)
      Balancing the Fastest Possible Speed with Service Stability

      Connect's DLM is unique to BT and is the next step forward in line speed management, making use of the increased configuration options available with ADSL2+.

      DLM works by logging and monitoring actual line performance every 15 minutes and using this information to stabilise the line, avoiding lost connections and interruptions to service. A 'maximum stable rate' is set by monitoring line performance over the first 10 days in service, and DLM then oversees the process automatically. DLM has three key elements:
      Active Line Optimisation – if performance falls outside pre-set limits, the line is 'retrained' by reducing the speed until an acceptable level of stability is established. When a line has been retrained, it will speed up and return to the maximum stable rate.
      Intelligent Profiling – using existing line performance data to set the best starting profile for a new or re-graded line reduces 'early life' faults.
      Service Stability Policies – offering flexibility in balancing speed and stability by customising DLM to match the performance requirements of different services.

      Source: BT Wholesale

    11. #10
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      Re: Snr?

      Quote Originally Posted by Isitme View Post
      It is normal for the noise on any line to change over a period. That is why you have a noise margin, it is supposed to compensate for changes on the line. For some reason, your line has a very big swing in the noise present on the line, too big for the normal noise margin to compensate. This can only be caused by a fault somewhere, no matter what BTO or Sky may say. They seem to have done everything possible to trace or cure the fault, to little effect. If you are not happy with what you have now, your only solution may be to go to another ISP and hope they can give a better result. The problem is if this is an inherent line fault, then it does not matter what ISP you go to, it is still going to be there.
      Yes i was always concerned if the fault is inherently to do with the line itself. As you say, if i move to another ISP, i may still have the same issue
      I've looked at ISPs, and a possible option maybe BE on a 3 month contract.
      Not sure how their service is.

      Is there anyway, hope in chance the problem i'm experiencing is related to Sky equipment? What are the possibilities?
      My only thinking is everyone connected to the same hardware would experience the same fault. Not just me rite?

      As this is caused by a fault somewhere.....what possible options did you have in mind? I'm unsure that the line itself is a problem, due to the number of times i've had it swapped (i.e. E side x2, D side x3) and the with the number times they've performed HAWK or other line tests. All turn out fine.

      Do you think REIN interefence on the line is a possiblity based on the severity of it.

      Btw thanks for your reply...

     

     
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