SNR and Loop Attenuation figures?

What are the actual minimum SNR and max Loop Attneuation figures for 1Mb and
2Mb connections that BT Wholesale work to?

Jon.

Jon Eyes <(E-Mail Removed)> wrote:
: What are the actual minimum SNR and max Loop Attneuation figures for 1Mb and
: 2Mb connections that BT Wholesale work to?

They don't use SNR at all in their number checker - to the annoyance of people
with high attenuation but good SNR.

It's 43dB for 2Mb (I know as I am outside it!) 60dB (maybe!) for 1Mb.

On Fri, 9 Sep 2005 10:43:54 +0000 (UTC), Brian McIlwrath
<(E-Mail Removed)> wrote:

>Jon Eyes <(E-Mail Removed)> wrote:
>: What are the actual minimum SNR and max Loop Attneuation figures for 1Mb and
>: 2Mb connections that BT Wholesale work to?
>
>They don't use SNR at all in their number checker - to the annoyance of people
>with high attenuation but good SNR.
>
>It's 43dB for 2Mb (I know as I am outside it!) 60dB (maybe!) for 1Mb.
Is it possible to bring the attenuation down? I have 59dB on a 1Meg
connection.

Any ideas?

UpStream
Noise Margin 22 dB
Output Power 12 dBm
Attenuation 31.5 dB

DownStream
Noise Margain 9 dB
Output Power 17.5 dBm
Attenuation 59 dB

In article <(E-Mail Removed)>,
(E-Mail Removed) says...

> Any ideas?
>
> UpStream
> Noise Margin 22 dB
> Output Power 12 dBm
> Attenuation 31.5 dB
>
> DownStream
> Noise Margain 9 dB
> Output Power 17.5 dBm
> Attenuation 59 dB
>

You can't significantly alter the attenuation from within the premesis.
By all means try into the test socket behind the master faceplate,
without using a filter, but I suspect all you'll do is increase your
SNR. You certainly won't obtain the ~32 fold increase in signal strength
required (if my dodgy maths is right) just by moving to your master
socket. I'm afraid for the time being you're going to be stuck with
1Mbit

Alex

On Fri, 9 Sep 2005 14:39:46 +0100, Alex Crosby <(E-Mail Removed)>
wrote:

>In article <(E-Mail Removed)>,
>(E-Mail Removed) says...
>
>> Any ideas?
>>
>> UpStream
>> Noise Margin 22 dB
>> Output Power 12 dBm
>> Attenuation 31.5 dB
>>
>> DownStream
>> Noise Margain 9 dB
>> Output Power 17.5 dBm
>> Attenuation 59 dB
>>
>
>You can't significantly alter the attenuation from within the premesis.
>By all means try into the test socket behind the master faceplate,
>without using a filter, but I suspect all you'll do is increase your
>SNR. You certainly won't obtain the ~32 fold increase in signal strength
>required (if my dodgy maths is right) just by moving to your master
>socket. I'm afraid for the time being you're going to be stuck with
>1Mbit
>
>Alex

Actually I am quite glad you said that. I am moving my ISP to another
provider and now I dont need to consider 2Meg offers, only the 1 Meg.

It will make my job of selecting an ISP that much easier

Now Plusnet, F2S or Metronet? Theres a quandry!

cheers

Harry

Harry <(E-Mail Removed)> wrote:

: Actually I am quite glad you said that. I am moving my ISP to another
: provider and now I dont need to consider 2Meg offers, only the 1 Meg.

Your SNR (at 9dB) is too low to cope with 2Mb anyway - it would drop by
>6dB with the speed increase. While I managed to get 2Mb at a bit above
BT's normal limits (46dB rather than 43) my SNR never drops below 11dB
at the higher speed!

Brian McIlwrath wrote:
> Harry <(E-Mail Removed)> wrote:
>
> : Actually I am quite glad you said that. I am moving my ISP to another
> : provider and now I dont need to consider 2Meg offers, only the 1 Meg.
>
> Your SNR (at 9dB) is too low to cope with 2Mb anyway - it would drop by
>
>>6dB with the speed increase. While I managed to get 2Mb at a bit above
>
> BT's normal limits (46dB rather than 43) my SNR never drops below 11dB
> at the higher speed!

It depends on whether BT's method of measuring loop attenuation shows
the same figure you mention or not, IIRC they often see a figure of 3 or
more dB lower than that typically shown by a connected modem.

--

Brian Morrison

please observe reply-to address

Brian Morrison <(E-Mail Removed)> wrote:

: It depends on whether BT's method of measuring loop attenuation shows
: the same figure you mention or not, IIRC they often see a figure of 3 or
: more dB lower than that typically shown by a connected modem.

But the ultimate thing that counts is SNR! BT cannot measure this but they
*CAN* estimate attenuation given their knowledge of line runs. Whatever
the real attenuation the SNR on my line is *easily* enough for 2Mb - despite
the line checker saying that this is out of the question.

Brian McIlwrath <(E-Mail Removed)> wrote:
> Brian Morrison <(E-Mail Removed)> wrote:
>
> : It depends on whether BT's method of measuring loop attenuation shows
> : the same figure you mention or not, IIRC they often see a figure of 3 or
> : more dB lower than that typically shown by a connected modem.
>
> But the ultimate thing that counts is SNR! BT cannot measure this but they
> *CAN* estimate attenuation given their knowledge of line runs. Whatever
> the real attenuation the SNR on my line is *easily* enough for 2Mb - despite
> the line checker saying that this is out of the question.

Assuming your modem is telling the truth.
Many are broken.

Ian Stirling <(E-Mail Removed)> wrote:

: Assuming your modem is telling the truth.
: Many are broken.

I think that 700+hours current router uptime and zero problems
in the two months I have have 2Mb rather clinches the fact that
it is right!!! (which is hardly surprising as I am only very
slightly outside BT guidance for 2Mb!)