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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.

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  #1  
Old June 29th 04, 06:30 PM posted to uk.telecom.broadband
Richard Rollins
external usenet poster
 
Posts: 2
Default Noise level

My line failed the test due to the noise on it being in excess of the 60db
limit. Does anyone know what the limit is for the 10km limit they are
testing.


  #2  
Old June 29th 04, 08:33 PM posted to uk.telecom.broadband
marky
external usenet poster
 
Posts: 7
Default Noise level

the distance doesnt matter, with a signal to noise ratio of that, adsl just
wont work, sorry
"Richard Rollins" wrote in message
...
My line failed the test due to the noise on it being in excess of the 60db
limit. Does anyone know what the limit is for the 10km limit they are
testing.




  #3  
Old June 29th 04, 08:59 PM posted to uk.telecom.broadband
Sunil Sood
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Posts: 1,590
Default Noise level

"Richard Rollins" wrote in message

My line failed the test due to the noise on it being in excess of the
60db limit. Does anyone know what the limit is for the 10km limit
they are testing.


There is no limit for the trial - they are trying everything to see what
works and what doesn't..

I would say the new limit will be at least 70dB.

Regards
Sunil


  #4  
Old June 29th 04, 09:30 PM posted to uk.telecom.broadband
Old Codger
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Posts: 363
Default Noise level

"Richard Rollins" wrote in message
...
My line failed the test due to the noise on it being in excess of
the 60db limit. Does anyone know what the limit is for the 10km
limit they are testing.

"marky" wrote in message

the distance doesnt matter, with a signal to noise ratio of that,
adsl just wont work, sorry


In excess of 60 db would be an exceptionally good signal to noise ratio
(lots of signal and very little noise).

However it is a high line loss (which is related to distance) and that is
why you may not be able to get ADSL.

--
Old Codger
e-mail use reply to field

What matters in politics is not what happens, but what you can make people
believe has happened. [Janet Daley 27/8/2003]




  #5  
Old June 29th 04, 09:31 PM posted to uk.telecom.broadband
Ian Stirling
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Posts: 807
Default Noise level

marky wrote:
the distance doesnt matter, with a signal to noise ratio of that, adsl just
wont work, sorry


looks at current attenuation

63.9dB.
Working well.
SNR of 11dB.
  #6  
Old June 29th 04, 10:38 PM posted to uk.telecom.broadband
Old Codger
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Posts: 363
Default Noise level

"Brian Morrison" wrote in message
news

Generally, provided the signal:noise ratio is adequate the absolute
attenuation isn't a problem until the signal is sliding into the
irreducible noise floor due to thermal effects. But SNR can reduce if
noise is induced in an otherwise OK connection, my SNR margin can be
as high as 36dB, but sometimes it is in the 6-10dB region for short
periods. The modem copes, but if my loop attenuation were higher than
43.5dB it would be more likely to cause problems when this happens.


My downstream attenuation is 52/53 dB. S/N is rarely above 10 dB, and I
have never seen it above 15 dB. Currently S/N is 6 dB. I do get periods
when sync will drop for very short intervals, sometimes annoyingly often,
but when the S/N is down at 5 or 6 dB the connection is usually as solid as
a rock.

--
Old Codger
e-mail use reply to field

What matters in politics is not what happens, but what you can make people
believe has happened. [Janet Daley 27/8/2003]


  #7  
Old June 29th 04, 10:51 PM posted to uk.telecom.broadband
marky
external usenet poster
 
Posts: 7
Default Noise level

being a broadband engineer for BT, I was just pointing out that with a line
loss such as 60db, it will not be stable, the other guy that said he had 63
db, how do you know that,?.....we have various ways to test, but not any
available to the public.


"Sunil Sood" wrote in message
...
"Richard Rollins" wrote in message

My line failed the test due to the noise on it being in excess of the
60db limit. Does anyone know what the limit is for the 10km limit
they are testing.


There is no limit for the trial - they are trying everything to see what
works and what doesn't..

I would say the new limit will be at least 70dB.

Regards
Sunil




  #8  
Old June 30th 04, 12:27 AM posted to uk.telecom.broadband
Ian Stirling
external usenet poster
 
Posts: 807
Default Noise level

marky wrote:
being a broadband engineer for BT, I was just pointing out that with a line
loss such as 60db, it will not be stable, the other guy that said he had 63
db, how do you know that,?.....we have various ways to test, but not any
available to the public.


I captured a BT engineer and have him tied down in my dungeon, as well
as assorted plumbers and other tradesmen.

Be warned, they are picky eaters, he turned his nose up at the Sky
engineer, eventually I had to provide Ketchup.
  #9  
Old July 6th 04, 07:15 PM posted to uk.telecom.broadband
|Me|
external usenet poster
 
Posts: 1
Default Noise level


"Old Codger" wrote in message
...
"Brian Morrison" wrote in message
news

Generally, provided the signal:noise ratio is adequate the absolute
attenuation isn't a problem until the signal is sliding into the
irreducible noise floor due to thermal effects. But SNR can reduce if
noise is induced in an otherwise OK connection, my SNR margin can be
as high as 36dB, but sometimes it is in the 6-10dB region for short
periods. The modem copes, but if my loop attenuation were higher than
43.5dB it would be more likely to cause problems when this happens.


My downstream attenuation is 52/53 dB. S/N is rarely above 10 dB, and I
have never seen it above 15 dB. Currently S/N is 6 dB. I do get periods
when sync will drop for very short intervals, sometimes annoyingly often,
but when the S/N is down at 5 or 6 dB the connection is usually as solid

as
a rock.

--



I use Solwise 715 routers and when I connect via telnet I can ask for ADSL
performance figures and this is what I see

2 Meg Plusnet connection been working fine for over 2 and a half years now


Login successful

-- adsl show perf
Downstream :
Noise Margin : 6.5 dB
Attenuation : 64.5 dB
Output Power : 19
Upstream :
Noise Margin : 8.5 dB
Attenuation : 31.5 dB
Output Power : 9

--

2 Meg Plusnet connection been working fine for over 1 year now

Login successful

-- adsl show perf
Downstream :
Noise Margin : 7.0 dB
Attenuation : 63.5 dB
Output Power : 19
Upstream :
Noise Margin : 9.5 dB
Attenuation : 30.5 dB
Output Power : 9

--

So if 60db is the maximum how the hell have I got 2 fully working 2 meg
connections well it ain't what you know its who you know


Are these figures bad then?

cheers for all replies


  #10  
Old July 8th 04, 09:32 PM posted to uk.telecom.broadband
Tim Clark
external usenet poster
 
Posts: 179
Default Noise level

In article ,
Brian Morrison writes:


On Tue, 29 Jun 2004 18:30:57 +0100, in article
"Richard Rollins"
wrote:

My line failed the test due to the noise on it being in excess of the 60db
limit. Does anyone know what the limit is for the 10km limit they are
testing.


You mean it failed the attenuation limit. As for the extended reach trial,
there is no set limit, but the results of the trial will be used to revise
the existing limits upward provided that the majority of participants get
good performance.

Generally, provided the signal:noise ratio is adequate the absolute
attenuation isn't a problem until the signal is sliding into the
irreducible noise floor due to thermal effects.


Given the power level of the ADSL signal at launch (which I don't know),
how much attenuation is required to take that signal down to the thermal
noise level?

--
Tim Clark
 




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