How can I improve my signal noise margin.

Hi,

Is there anyway I can improve my signal noise margin to improve my speed, As I feel could be getting a faster service, if my line noise was better,
what do you think?

ADSL Link Downstream Upstream
Connection Speed 3712 kbps 448 kbps
Line Attenuation 49 db 13.5 db
Noise Margin 14 db 22 db

Test1 comprises of Best Effort Test: -provides background information.
IP profile for your line is - 3000 kbps
DSL connection rate: 448 kbps(UP-STREAM) 3712 kbps(DOWN-STREAM)
Actual IP throughput achieved during the test was - 2804 kbps

1. Fit a filtered ADSL faceplate
2. Connect router directly to the faceplate by a short length cable.
3. If necessary, run Cat5 ethernet back to PC

The idea is to keep unfiltered extension wiring as short as possible. If you don't have extension wiring (either fixed or trailing), ignore the above advice.

HI zebedeee,
Thank you for the quick reply.

I do have a filtered ADSL faceplate on the master, I am not using the master at the moment, but I have tested it in the past, the signal noise stays about the same as on my extension.

The length of the cable from the faceplate to router is about 1M.

Can you think of anything else I could try?

Thanks again for reply

In reply to:

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Can you think of anything else I could try?

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I don't think your SNR margin is the problem. If you have more than 6dB I would expect a higher sync speed so it is something else which is causing the problem. Attenuation is high but whether that is enough to explain the low sync rate I don't know. I would ask you ISP to get BT to examine it and see, but I doubt whether you will have much joy as it is likely to be within what they deem to be acceptable limits.

An impractical alternative is to move closer to the exchange.

On the case of the "fly lead" would ferrite chokes as on other signal equipment make a difference. From the amateur radio days I got the idea, just figured it would help cut down on emi on the line from fridges, microwaves and god knows what else...??

Anyone else have any thoughts on this..??

You don't need to improve your downstream noise margin so much, as getting your ISP to reduce it. Ask them to alter it as it is set by the exchange equipment.

Setting the noise margin to 6dB or 9dB should give you an increase in sync speed unless there is a lot of cyclical or bursty noise on the line and it becomes too unstable to work reliably.

Noise on the line is not the same thing as noise margin which is the difference in the power of the ADSL signal you want and the noise signal you don't.

There isn't much you can do about noise on the line if it is coming from external sources other than get another line installed and take a chance that it will perform better. But it could be worse.

That's the whole point - you don't want to have unfiltered extensions - these act as radio aerials causing the SNR to drop at night, which could be the reason for your generous margins. Whether you're connected to the master, or the extension, the wire is still there acting as an aerial. You can have as many filtered (phone) extensions as you want, because they're filtered.

Ferrite chokes would be useless. They would attenuate both the noise and the signal, leaving you back at square one.

Post deleted by duster

Hi,
thanks for reply.

Do you think if I asked my isp(BT), they would understand, as their tec support is not good, and they dont seem able to fix problems about BroadBand, All they ever say is "its spyware, or my PC at fault, (which it is not).
At the moment my connecttion is rock stable, and stays up for over a month at a time,with no resets, untill BT force a new IP number on me.

When I put my home address in the bt web site that says how fast your broadband should be, it says I should get 5.5mb at my address, and not the 2.8mb that I do get.

Edited by deleted (Wed 14-Mar-07 09:09:52)