line attenuation

  Alf58 00:51 22 Jun 2007

I thought line attenuation was a fixed number and could not be changed. If this is the case why did my "local line attenuation" go from 37.5 to 38? Has my line started to decompose? Is it BT playing their games?

I'm just waiting for them to email my MAC code! They wont see me for dust: another satisfied customer ....NOT!

  STREETWORK 22:47 22 Jun 2007

The line is not suffering anything other than a drop in noise level, the lower the number the better...

  Alf58 22:58 22 Jun 2007

yes but mine went from 37.5 to 38. It is deteriorating.

  Dipso 23:25 22 Jun 2007

Was your router cold i.e. had it been off for some time when it connected with the attenuation of 38? Been reading reports of this happening, if your reset the router when it's warm the attenuation figure may then reduce.

Although it's true the figure is fixed, a .5 variation is nothing to worry about. I saw this recently on my line and put it down to the weather, it's back to normal now.

  CurlyWhirly 18:54 23 Jun 2007

The attenuation figure is just the average figure across all of the available frequencies used at any point in time.

My attenuation varies by 1 dB as it is either 54dB or 55dB but this makes no difference as my TRUE attenuation hasn't really changed only the WAY IT IS CALCULATED by my router.

  Brigit 23:21 14 Aug 2007

Hi I'm having great problems with AOL and my netgear router - sadly I just get a connection at night.

I've been trying to ask them the question about what is the acceptable range for Line Attenuation and Noise Margins and they don't know. Mine are

LA 63db downstream 15.5db upstream
NM 3db downstream 16db upstream

Can anybody throw any light on these - are they acceptable or are they way out and that's why I'm having so many problems. Thoughts appreciated. Thank you.

  Dipso 23:40 14 Aug 2007

A downstream attenuation of 63db basically means you have a long line to the local telephone exchange. Distance to the exchange is a factor in the quality of the connection. 63db is the maximum most routers can report so in reality it could be a higher figure. The good news is, the DG834G which I presume you have handles long lines well.

Your noise margin is very low at 3db, to be stable it needs to be a minimum of 6.

The only way you can try and stabilise the connection is to try and improve your internal phone wiring. Follow the tutorial click here and if possible try and connect through your master socket and if this is the new type with the removeable faceplate, try through the the test socket underneath, this will give you the best connection your line is able to provide.

Changing your filters to better quality ones could also see an improvement.

  Dipso 23:50 14 Aug 2007

If there's anything you're unsure about with regard to the tutorial or any else for that matter, don't hesitate to ask.

  Brigit 21:51 15 Aug 2007

Thank you so much Dipso. I'll give the tutorial ago. Both BT and AOL are passing me from one to the other. I can only get the internet at night - AOL blame BT and BT blame AOL and I'm stuck now to the night shift. Who do you think is to blame?
BT dug up the road for 1km to put in a new cable for me and I had hoped that would be me sorted!

Interestingly, I get a much better success rate by using an extension socket rather than the main BT socket.

Any thoughts appreciated............Brigit

  Brigit 22:16 15 Aug 2007

Are there any particular types of filter you would recommend? I'm using the ASDL ones supplied by AOL.


  Dipso 23:35 15 Aug 2007

Yes, with a long line a good quality filter can make all the difference. The XF-1e from click here is one of the best available. I got mine from click here as they were a bit cheaper...very good quick service too.

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