Noise and Attenuation figures...are these OK?

Hi all

My 3com wireless router is reporting the following figures.

Upstream Downstream

Noise Margin
22 dB 9 dB

Output Power
12 dBm 17.5 dBm

Attenuation
31.5 dB 59 dB


These are on a 1Mb link with the exchange being about 2.5km from the
house.

Are these OK as I suspect the Downstream figures are a little off?

TIA

Harry

"Harry" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Hi all
>
> My 3com wireless router is reporting the following figures.
>
> Upstream Downstream
>
> Noise Margin
> 22 dB 9 dB
>
> Output Power
> 12 dBm 17.5 dBm
>
> Attenuation
> 31.5 dB 59 dB
>
>
> These are on a 1Mb link with the exchange being about 2.5km from the
> house.
>
> Are these OK as I suspect the Downstream figures are a little off?
>
> TIA
>
> Harry

My downstream is 63dB with 11dB SNR margin. Yours arn't much different so I
suspect they are about right.

On Fri, 13 May 2005 09:40:42 +0100, Harry <(E-Mail Removed)> wrote:

>Upstream Downstream
>Noise Margin
>22 dB 9 dB
>Output Power
>12 dBm 17.5 dBm
>Attenuation
>31.5 dB 59 dB
>
>These are on a 1Mb link with the exchange being about 2.5km from the
>house.

the attenuation points to a line length more like 6km, which is not
impossible with "round the houses" routing.

Noise margin is OK, 59 dB is about BT's limit for 1M.

You would expect maybe a bit more margin, Dave gets 63 + 11 = 74
whereas you have 59 + 9 = 68 so 6 dB more of noise (assuming Dave is
also on 1M, if he's on 512k that explains the difference).

Phil
--
Tiscali - dialup speeds at Broadband prices.
AOL - the unlimited ISP of choice for heavy downloaders.

On Fri, 13 May 2005 10:14:40 +0100, Phil Thompson
<(E-Mail Removed)> wrote:

>On Fri, 13 May 2005 09:40:42 +0100, Harry <(E-Mail Removed)> wrote:
>
>>Upstream Downstream
>>Noise Margin
>>22 dB 9 dB
>>Output Power
>>12 dBm 17.5 dBm
>>Attenuation
>>31.5 dB 59 dB
>>
>>These are on a 1Mb link with the exchange being about 2.5km from the
>>house.
>
>the attenuation points to a line length more like 6km, which is not
>impossible with "round the houses" routing.
>
>Noise margin is OK, 59 dB is about BT's limit for 1M.
>
>You would expect maybe a bit more margin, Dave gets 63 + 11 = 74
>whereas you have 59 + 9 = 68 so 6 dB more of noise (assuming Dave is
>also on 1M, if he's on 512k that explains the difference).
>
>Phil
Is their anything I can do at my end to improve these figures?
Specific cabling, siting, filters etc? Or is this just something I
have to live with?

cheers

Harry

Harry <(E-Mail Removed)> wrote in news:(E-Mail Removed):

> Is their anything I can do at my end to improve these figures?
> Specific cabling, siting, filters etc? Or is this just something I
> have to live with?

Try the connection directly in the master socket (if you have a master
socket with a removable lower section, remove that and plug it into the
socket behind). If the figures are the same then you're unlikely to get
any better stats.

--
Phil
http://www.philipchung.co.uk/

On Fri, 13 May 2005 11:07:58 +0100, Harry <(E-Mail Removed)> wrote:

>Is their anything I can do at my end to improve these figures?
>Specific cabling, siting, filters etc? Or is this just something I
>have to live with?

try it in the test socket first, that tells you what arrives at your
premises.

Use a BT to RJ11 adaptor to plug into the back socket shown at
http://www.clarity.it/telecoms/adsl_faceplate.htm#part3 than there is
no extensions or filters in the system.

If there is a big difference is results (margin may be better) then
you can try putting a microfilter between the back test socket and the
front plate, with the modem plugged into that filter. This simulates a
faceplate filter, which is the neat solution.

But if its not broke, don't try to fix it :-)

Phil
--
Tiscali - dialup speeds at Broadband prices.
AOL - the unlimited ISP of choice for heavy downloaders.

"Phil Thompson" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> On Fri, 13 May 2005 09:40:42 +0100, Harry <(E-Mail Removed)> wrote:
>
> >Upstream Downstream
> >Noise Margin
> >22 dB 9 dB
> >Output Power
> >12 dBm 17.5 dBm
> >Attenuation
> >31.5 dB 59 dB
> >
> >These are on a 1Mb link with the exchange being about 2.5km from the
> >house.
>
> the attenuation points to a line length more like 6km, which is not
> impossible with "round the houses" routing.
>
> Noise margin is OK, 59 dB is about BT's limit for 1M.
>
> You would expect maybe a bit more margin, Dave gets 63 + 11 = 74
> whereas you have 59 + 9 = 68 so 6 dB more of noise (assuming Dave is
> also on 1M, if he's on 512k that explains the difference).

Yep, I'm syncing at 512k.

>
> Phil
> --
> Tiscali - dialup speeds at Broadband prices.
> AOL - the unlimited ISP of choice for heavy downloaders.

On Fri, 13 May 2005 10:20:47 +0000 (UTC), Phil <(E-Mail Removed)>
wrote:

>Harry <(E-Mail Removed)> wrote in news:(E-Mail Removed):
>
>> Is their anything I can do at my end to improve these figures?
>> Specific cabling, siting, filters etc? Or is this just something I
>> have to live with?
>
>Try the connection directly in the master socket (if you have a master
>socket with a removable lower section, remove that and plug it into the
>socket behind). If the figures are the same then you're unlikely to get
>any better stats.
I will try it tonight and get back to you on Monday.

cheers

Harry

On Fri, 13 May 2005 11:21:21 +0100, Phil Thompson
<(E-Mail Removed)> wrote:

>On Fri, 13 May 2005 11:07:58 +0100, Harry <(E-Mail Removed)> wrote:
>
>>Is their anything I can do at my end to improve these figures?
>>Specific cabling, siting, filters etc? Or is this just something I
>>have to live with?
>
>try it in the test socket first, that tells you what arrives at your
>premises.
>
>Use a BT to RJ11 adaptor to plug into the back socket shown at
>http://www.clarity.it/telecoms/adsl_faceplate.htm#part3 than there is
>no extensions or filters in the system.
>
>If there is a big difference is results (margin may be better) then
>you can try putting a microfilter between the back test socket and the
>front plate, with the modem plugged into that filter. This simulates a
>faceplate filter, which is the neat solution.
>
>But if its not broke, don't try to fix it :-)
>
>Phil
I will check it all out tonight..

cheers

Harry

Phil Thompson wrote:
> On Fri, 13 May 2005 09:40:42 +0100, Harry <(E-Mail Removed)> wrote:
>
>> Upstream Downstream
>> Noise Margin
>> 22 dB 9 dB
>> Output Power
>> 12 dBm 17.5 dBm
>> Attenuation
>> 31.5 dB 59 dB
>>
>> These are on a 1Mb link with the exchange being about 2.5km from the
>> house.
>
> the attenuation points to a line length more like 6km, which is not
> impossible with "round the houses" routing.

Yes I have the same problem here. The exchange is only about 3km away but
the way the pipes are laid it is over 6km

> Noise margin is OK, 59 dB is about BT's limit for 1M.

Both my routers have both said my line has 59db but BT insist it is 62-63 so
I cannot get 1M