A Broadband and ADSL forum. BroadbanterBanter

Welcome to BroadbanterBanter.

You are currently viewing as a guest which gives you limited access to view most discussions and other FREE features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload your own photos and access many other special features. Registration is fast, simple and absolutely free so please, join our community today.

Go Back   Home » BroadbanterBanter forum » Newsgroup Discussions » uk.telecom.broadband (UK broadband)
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

uk.telecom.broadband (UK broadband) (uk.telecom.broadband) Discussion of broadband services, technology and equipment as provided in the UK. Discussions of specific services based on ADSL, cable modems or other broadband technology are also on-topic. Advertising is not allowed.

Is this line noisy?



 
 
Thread Tools Display Modes
  #1  
Old September 27th 05, 02:01 PM posted to uk.telecom.broadband
Stroller
external usenet poster
 
Posts: 80
Default Is this line noisy?

I have a friend whose ADSL keeps on dropping and I'm thinking of
trying to pressure his ISP into sending out a BT engineer. His BT
Voyager 105 ADSL modem is plugged into a splitter at the master socket
and there are no other phones connected to the line.

The CTRL-f1 panel of the Voyager 105 utility shows the following figures:

Attenuation is 50dB down, 31.5dB up.
SNR margin 11dB down, 9.5 dB up.
http://stuff.stroller.uk.eu.org/ADSL.gif

are those any good, or am I going to have to fight to get this seen to?

Thanks in advance,

Stroller.

  #2  
Old September 27th 05, 03:28 PM posted to uk.telecom.broadband
Spack
external usenet poster
 
Posts: 104
Default Is this line noisy?

Brian wrote on Tue, 27 Sep 2005 14:25:19 +0100:

Stroller wrote:
I have a friend whose ADSL keeps on dropping and I'm thinking of trying
to pressure his ISP into sending out a BT engineer. His BT Voyager 105
ADSL modem is plugged into a splitter at the master socket and there are
no other phones connected to the line.

The CTRL-f1 panel of the Voyager 105 utility shows the following figures:

Attenuation is 50dB down, 31.5dB up.
SNR margin 11dB down, 9.5 dB up.
http://stuff.stroller.uk.eu.org/ADSL.gif

are those any good, or am I going to have to fight to get this seen to?


You'd normally hope to get downstream attenuation+SNR margin to equal at
least 70, so you are about 9 or 10 dB short. These figures will worsen
with extra interference (evening time, greater usage of other ADSL
connections in same cable bundle, mains noise etc), hence the drop-outs.


That makes no sense. By your reply you seem to imply that a 70db
attentuation with 0db SNR would be fine.

Surely you want attenuation as low as possible (higher the attenuation the
longer the signal has travelled), SNR as high as possible (the higher it is,
the less noise you have). Adding the figures together and saying "should be
at least X" just doesn't work. Attentuation 30db and SNR 30db would be a
great line, yet from above you'd be saying it's not.

Dan


  #3  
Old September 27th 05, 04:34 PM posted to uk.telecom.broadband
Martin Underwood
external usenet poster
 
Posts: 114
Default Is this line noisy?

Brian Morrison wrote in
:

Spack wrote:
Brian wrote on Tue, 27 Sep 2005 14:25:19 +0100:


Stroller wrote:

I have a friend whose ADSL keeps on dropping and I'm thinking of
trying to pressure his ISP into sending out a BT engineer. His BT
Voyager 105 ADSL modem is plugged into a splitter at the master
socket and there are no other phones connected to the line.

The CTRL-f1 panel of the Voyager 105 utility shows the following
figures: Attenuation is 50dB down, 31.5dB up.
SNR margin 11dB down, 9.5 dB up.
http://stuff.stroller.uk.eu.org/ADSL.gif

are those any good, or am I going to have to fight to get this
seen to?


My advice to the OP is correct though; he should be seeing a much
better SNR than he describes on a 50dB loss line, it should be a
minimum of 20dB, and more like 25dB. Clearly there is some
interference and I suspect it could be local and coming in through
unbalanced ring wiring on extensions.


Yes. I'd suggest the first thing to try is to disconnect any other wiring in
the house, if possible. For example, disconnect anything connected to the
other arm of the splitter between the modem's microfilter.

Presumably the most important figure is not attenuation but noise margin:
the amount by which the signal exceeds the noise. As long as the modem had a
good enough amplifer, it would not matter if the signal was severely
attenuated, *provided* that the SNR was still good.

My equivalent figures (sorry to make the OP jealous!) are

Attenuation 6.5 db (D) 5.5 db (U)
Noise Margin 30.3 db (D) 29.0 db (U)

Mind you, I'm about 100 m from the exchange and I'd be surprised if the
wiring was more than about 300 m in length allowing for it being routed via
the road.









  #4  
Old September 27th 05, 07:02 PM posted to uk.telecom.broadband
Phil Thompson
external usenet poster
 
Posts: 2,720
Default Is this line noisy?

On Tue, 27 Sep 2005 15:28:53 +0100, "Spack"
wrote:

Attentuation 30db and SNR 30db would be a
great line, yet from above you'd be saying it's not.


it wouldn't be a great line, as if it had less noise it would have a
bigger SNR and hence be able to support higher speeds than the above
combination could.

Phil
--
Tiscali - dialup speeds at Broadband prices, see
http://bbs.adslguide.org.uk/postlist...&Board=tiscali

AOL - the unlimited ISP of choice for heavy downloaders.
  #5  
Old September 27th 05, 07:38 PM posted to uk.telecom.broadband
Phil Thompson
external usenet poster
 
Posts: 2,720
Default Is this line noisy?

On Tue, 27 Sep 2005 16:34:49 +0100, "Martin Underwood"
wrote:

My equivalent figures (sorry to make the OP jealous!) are

Attenuation 6.5 db (D) 5.5 db (U)
Noise Margin 30.3 db (D) 29.0 db (U)


I get 41 dB of margin with 11 dB of attenuation, so its your turn to
go green ;-)

Phil
--
Tiscali - dialup speeds at Broadband prices, see
http://bbs.adslguide.org.uk/postlist...&Board=tiscali

AOL - the unlimited ISP of choice for heavy downloaders.
 




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Lifting handset drops ADSL - noisy line in dry weather! Mark Vickers uk.telecom.broadband (UK broadband) 9 September 3rd 05 10:10 AM
dacs removed - not much improvement in dialup speed - line gain/line card banzai uk.telecom.broadband (UK broadband) 11 May 19th 04 05:24 PM
Line distance or line quality Beck uk.telecom.broadband (UK broadband) 4 February 2nd 04 04:44 PM
Can turning up line signal cause poor line attenuation? Simon Fearby uk.telecom.broadband (UK broadband) 1 August 31st 03 05:24 PM
Line Noise on BT phone line, Will ADSL work? -Captain-Pugwash- uk.telecom.broadband (UK broadband) 18 July 21st 03 06:03 PM


All times are GMT +1. The time now is 06:59 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.Content Relevant URLs by vBSEO 2.4.0
Copyright 2004-2020 BroadbanterBanter.
The comments are property of their posters.