Unstable SNR Margin Downstream

[Don-haddad]

Hi I'm new to IDnetters

I'm having some  problem with my connection for 2 weeks now... I think it's my SNR Margin (downstream)

Let me give you some info about my router and Connection...
Router: TP-LINK TD-W8901G
Current Firmware Version: 3.0.1 Build 100901 Rel.23594
Connection speed: 512 kbps
I'm Connected to my Router with a Cable not Wireless
(plz ask me if you need more info)

why I'm saying it's my SNR Margin downstream
cuz i used to monitor my Connection Status and everything seems to be same(when i had better Connection 2 weeks ago) expect SNR Margin Downstream.. I used to get around 30's now I'm getting 6~6.8 when i restart my connection... but it always get lower and lower till it drops to Negative and lose connection and reconnect itself and give me around 6 SNR Margin Downstream and cycle repeats... the Cycle taking about 15 min... here's some more info

first when i get connection

Code Select Expand


Downstream Upstream
SNR Margin: 6.1 33.2 db
Line Attenuation: 38.0 24.8 db
Data Rate: 512 254 kbps
Max Rate: 872 1947 kbps
POWER:  10.9 14.3 dbm
CRC:1499 0


Code Select Expand


Downstream Upstream
SNR Margin: 3.6 30.5 db
Line Attenuation: 38.0 24.8 db
Data Rate: 512 254 kbps
Max Rate: 872 1947 kbps
POWER:  10.9 14.3 dbm
CRC:1499 0


Code Select Expand


Downstream Upstream
SNR Margin: 1.7 30.7 db
Line Attenuation: 38.0 24.8 db
Data Rate: 512 254 kbps
Max Rate: 828 1905 kbps
POWER:  10.9 14.3 dbm
CRC:1513 0


Code Select Expand

Downstream Upstream
SNR Margin:0.0 33.0 db
Line Attenuation:38.0 24.8 db
Data Rate:512 254 kbps
Max Rate:952 1947 kbps
POWER:10.7 14.3 dbm
CRC:2110 0   

Code Select Expand

Downstream Upstream
SNR Margin:-1.-1 31.5 db
Line Attenuation:38.0 24.8 db
Data Rate:512 254 kbps
Max Rate:912 1947 kbps
POWER:10.7 14.3 dbm
CRC:2776 0

then i lose Connection...

[Rik]

Hi and welcome to the forum. I should point out to other members that you're not UK-based, so the 'odd' sync speeds are nothing to do with BT.

If you were in the UK, I'd be wondering why your sync speed is so low for a 38db line attenuation. However, the symptoms you demonstrate are typical of a line affected by noise, either locally generated, eg air-conditioning system, fridge, freezer etc, or somewhere between you and the exchange. Another possibility is an unfiltered device connected to the line, but this is less likely as that would tend to make the line fall over and stay fallen over.

Is the problem time related, ie does it occur at particular times of day?

[Steve]

 

I'm guessing your on a fixed rate connection as the previous margin of 30 would fit.? and as Rik says there some noise around somewhere which you need to locate.

[Don-haddad]

First thx alot for the warm Welcome 

Second if this Forum is for only UK based members I'm really sorry for posting... i really didn't know that...

and about my problem i think i located the Noise but not sure yet... my Cable goes right next to an air-conditioning System... i will cut the power from it and Monitor my Connection Status again... if that's the problem i  think i will have to relocate my Cable... that's hell of a work

i will keep you informed with the Results...

thanks again

[Steve]

NP our members are largely UK based but I think the point Rik made was that your adsl characteristics may differ from the standard UK  phone line, but we'll try our best to help if we can.

[Rik]

We'll try and help anyone, but obviously we only really know the UK services, so can only give you more general advice.

If you're running Windows, download and install Routerstats:

http://www.vwlowen.co.uk/internet/files.htm
http://www.vwlowen.co.uk/moreinternet/files.htm

The program will create a graph of your noise margin over time, and so help to narrow the search for the source of the noise. If you have a battery-powered AM radio, de-tune it so that you can only hear white noise, then follow the line of your cabling. If it increases anywhere, there's a source of interference in that locality.

[Don-haddad]

I think the noise Source is not from my air-Conditioning system 
today i'm getting SNR margin downstream between 14~18 and not dropping lower(and better connection ofc)... I live in Syria, and my connection problem is at my work station... i work in industry so lots of other industrial neighbors around. I think one of them is effecting my connection, since all neighbors have machines eg (CNC mill/lathe machines,  textile Machines..etc) today is Friday and since most of the ppl take Friday as their Weekend... and today i have better connection... 

and Rik about the routerstats u told me to download and use.. i couldn't setup up the right configuration :S I don't have a good Experience with this...

[Rik]

From what you say, electrical interference from a neighbour seems highly likely. Unfortunately, that's very difficult to deal with. In the UK, we'd  first have to persuade British Telecom (the wholesale supplier of the service) that a problem existed, and then be lucky enough to get an engineer who would understand and be prepared to fit an RF filter to the line. Obviously, I don't know how things work in Syria, but essentially, that's what you're looking to achieve.

To help yourself, can you move the router as close as possible to the point at which the phone line enters the house (do you have master sockets?) and then run a longer ethernet cable to the computer? Ethernet segments can be up to 100m.

What problems did you have with Routerstats?

[Don-haddad]

From what you say, electrical interference from a neighbour seems highly likely. Unfortunately, that's very difficult to deal with. In the UK, we'd  first have to persuade British Telecom (the wholesale supplier of the service) that a problem existed, and then be lucky enough to get an engineer who would understand and be prepared to fit an RF filter to the line. Obviously, I don't know how things work in Syria, but essentially, that's what you're looking to achieve.

today i'm sure it's electrical interference from a neighbor.. today i'm having the same problem agian...

To help yourself, can you move the router as close as possible to the point at which the phone line enters the house (do you have master sockets?) and then run a longer ethernet cable to the computer? Ethernet segments can be up to 100m.

it's already been like that from first day.. my router is right next to the point which the phone line enters my workstation... about 20cm away on a desk..
but i think it's not a master socket

[Rik]

Obviously, I don't know what your master sockets look like, so it's difficult to advise. UK masters have a bottom portion of the faceplate which is removable, exposing a socket, just like a normal socket, which is connected directly to the exchange pair. We refer to this as the test socket. Do you have a similar system?

[armadillo]

Obviously, I don't know what your master sockets look like, so it's difficult to advise. UK masters have a bottom portion of the faceplate which is removable, exposing a socket, just like a normal socket, which is connected directly to the exchange pair. We refer to this as the test socket. Do you have a similar system?

Rik, obviously I don't know anything about Syrian telecoms either. But I would not necessarily agree with your definition of master socket, even in the UK. The master socket (indeed the only socket) in my house does not have a lower removable portion of faceplate. The faceplate is in one piece and there is no test socket behind it. The socket visible with the faceplate in position is all there is. That one and only socket is connected directly to the exchange pair. My house has no wired extensions.

So I think you could define a master socket as the socket which is directly connected to the exchange pair, regardless of its faceplate.

I thought the point of the split faceplate type, with a test socket, is that it enables extensions to be wired to it whilst still providing a test socket which is connected to nothing but the exchange pair.

Given that my single-socket master is about 40 years old, it might be more typical of configurations that are not cutting edge. Without maligning Syria, I would guess its telecoms are less cutting edge than, for example, Finland (which was very cutting edge when I worked in IT for a telecoms company).

[Rik]

I was trying to simplify things, 'Dill, as I have no knowledge of what to expect from a Syrian telco. However, finding out if there is a test socket was behind my question.

[armadillo]

Yes indeed. A test socket would be good.

[Rik]

Sadly, there isn't one.