Your forum username:
Do you already have an account?
Forgot your password?
  • Log in or Sign up


    Welcome to Sky User - The Unofficial Support Forum for everything Sky! - Proudly helping over 65k members.


    Advertisement

    Results 1 to 4 of 4

    Drop in Noise Margin

    This is a discussion on Drop in Noise Margin within the Sky Broadband help forums, part of the Sky Broadband help and support category; Weirdest thing happens, about 1745 EVERY night my noise margin drops from a solid 7-8db all day right down to ...

    1. #1
      AndyN's Avatar
      AndyN is offline Sky User Member
      Exchange: Langley Mill
      Broadband ISP: Max
      Router:
      Sky TV:
      Join Date
      Mar 2007
      Posts
      2
      Thanks
      0
      Thanked 0 Times in 0 Posts

      Drop in Noise Margin

      Weirdest thing happens, about 1745 EVERY night my noise margin drops from a solid 7-8db all day right down to abotu 2.9
      This causes my line which synchs at 5632 (and stays at that all day!) to drop to 4300 at which it stays throughout the night until I re-synch in the morning to get it back to 5600 (ish)

      Anyone got any ideas? Its definitely not anything on my line (from an inside point of view)


    2. Advertisement
    3. #2
      Saturday's Avatar
      Saturday is offline Sky User Super Mod
      Exchange:
      Broadband ISP: Sky Broadband Unlimited Pro
      Router: Sky Hub SR102
      Sky TV: Sky+HD box
      Join Date
      Sep 2006
      Posts
      6,086
      Thanks
      20
      Thanked 52 Times in 47 Posts

      Re: Drop in Noise Margin

      Welcome to the forum

      A drop in noise margin every evening is entirely normal and is caused by a number of things such as environmental factors and crosstalk. However, that said, a drop of 5db is a little greater than normal and this may indicate you have a noisy line which exacerbates this problem. You have posted no other info.

      Please take a little while to read the stickies in the forums (at the very least). You will find answers to questions such as yours plus a lot of other useful information. You might wish to start with the first sticky in my signature at the bottom of this post.

      Thread moved to the appropriate forum.

    4. #3
      AndyN's Avatar
      AndyN is offline Sky User Member
      Exchange: Langley Mill
      Broadband ISP: Max
      Router:
      Sky TV:
      Join Date
      Mar 2007
      Posts
      2
      Thanks
      0
      Thanked 0 Times in 0 Posts

      Re: Drop in Noise Margin

      Thanks for the reply, and the welcome

      I have 2 lines into the house, 1 is on BE (soon to be booted) and the other on Sky Max.
      Both faceplates are XTE-2005.
      The muppet who did the install of my second line seems to have 'spurred' it off the first line, I only noticed this on changing the face plates as theres no test socket in it, there is one on the first line socket (although i cant wire that socket to the faceplate, its just plugged in)
      Heres my stats, dont get me wrong, I know I'm a country mile from the Exchange but knowing i can get 5600 which then drops off is a tad annoying.

      Wanted to get sky max on my main line as well, but unfortunately the Sky system wont let them do it (for some reason) so I'm having to go BT. Anyways here's the stats


      /usr/sbin/adslctl: ADSL driver and PHY status
      Status: Showtime Channel: INTR, Upstream rate = 768 Kbps, Downstream rate = 5632 Kbps
      Link Power State: L0
      Mode: G.DMT
      Channel: Interleave
      Trellis: ON
      Line Status: No Defect
      Training Status: Showtime
      Down Up
      SNR (dB): 6.9 14.0
      Attn(dB): 54.0 31.5
      Pwr(dBm): 19.4 11.5
      Max(Kbps): 6208 1120
      Rate (Kbps): 5632 768
      G.dmt framing
      K: 177(0) 25
      R: 16 16
      S: 1 8
      D: 64 8
      ADSL2 framing
      MSGc: 1 1
      B: 177 25
      M: 1 8
      T: 1 1
      R: 16 16
      S: 1.0898 8.6153
      L: 1424 208
      D: 64 8
      Counters
      SF: 382568 382566
      SFErr: 6 0
      RS: 26014656 3251811
      RSCorr: 362803 12
      RSUnCorr: 98 0

      HEC: 4 0
      OCD: 0 0
      LCD: 0 0
      Total Cells: 86387427 0
      Data Cells: 26768920 0
      Drop Cells: 0
      Bit Errors: 0 0

      ES: 19 0
      SES: 16 0
      UAS: 21 0
      Total time = 1 hours 48 min 50 sec
      SF = 382568
      CRC = 6
      LOS = 21
      LOF = 0
      ES = 19
      Latest 1 day time = 1 hours 48 min 50 sec
      SF = 382568
      CRC = 6
      LOS = 21
      LOF = 0
      ES = 19
      Latest 15 minutes time = 3 min 50 sec
      SF = 13586
      CRC = 0
      LOS = 0
      LOF = 0
      ES = 0
      Previous 15 minutes time = 15 min 0 sec
      SF = 52930
      CRC = 0
      LOS = 2
      LOF = 0
      ES = 2
      Previous 1 day time = 0 sec
      SF = 0
      CRC = 0
      LOS = 0
      LOF = 0
      ES = 0
      15 minutes interval [-30 min to -15 min] time = 15 min 0 sec
      SF = 52989
      CRC = 2
      LOS = 3
      LOF = 0
      ES = 4
      15 minutes interval [-45 min to -30 min] time = 15 min 0 sec
      SF = 52931
      CRC = 0
      LOS = 1
      LOF = 0
      ES = 1
      15 minutes interval [-60 min to -45 min] time = 15 min 0 sec
      SF = 52930
      CRC = 0
      LOS = 5
      LOF = 0
      ES = 3

    5. #4
      Saturday's Avatar
      Saturday is offline Sky User Super Mod
      Exchange:
      Broadband ISP: Sky Broadband Unlimited Pro
      Router: Sky Hub SR102
      Sky TV: Sky+HD box
      Join Date
      Sep 2006
      Posts
      6,086
      Thanks
      20
      Thanked 52 Times in 47 Posts

      Re: Drop in Noise Margin

      Connecting at 5632kbps at an attenuation of 54db is very good but is really pushing your line to the limit. 4500kbps would be the "normal" connection speed for this attenuation with a relatively noise free line.

      Your line must be exceptionally good and your stats confirm this. Even connected at this speed only a very low level of errors is being recorded (these will however rise enormously as the noise margin drops below ~5db).

      You've only got two choices I'm afraid:
      • carry on as you are and deal with the drop outs every evening
      • push your noise margin up 3db or so and take the connection speed hit

      Personally I'd take the second choice as I don't think in normal everyday use I'd notice the difference between a connection of 5meg or 4meg. YMMV.

     

     

    Tags for this Thread

    Posting Permissions

    • You may not post new threads
    • You may not post replies
    • You may not post attachments
    • You may not edit your posts
    •  
    SkyUser - Copyright © 2006-2017. SatDish and NewsreadeR | SkyUser is in no way affiliated with Sky Broadband / BSkyB
    RIPA NOTICE: NO CONSENT IS GIVEN FOR INTERCEPTION OF PAGE TRANSMISSION