Fluctuating Noise Margin Resulting in Frequent Disconnections

[Najarak]

From being reliable for years my connection has today been intermittent. I am using a Netgear DG834 v4, bought in 2008, I have changed to using the test socket behind the faceplate so that everything else is disconnected.

The Netgear shows
Connection Speed 7616 down 448 up
Line attenuation 26db down 16db up
Noise margin 7.9db down 17.0db up

What happens is that the 7.9db down attenuation drops to about .5db and then disconnects, also the up attenuation also fluctuates. I cannot do a BT Speedtest as it refuses to do it, saying "Performance Tester is unable to run the speed test for your telephone number:0xxxx etc. Please check that it is th...".

I rang support today but was told to change filters etc.; as I have now eliminated the filters, with no improvement whatsoever. I know that BT are in the process of installing fibre to the cabinet at my exchange, could this work be causing the problems. I am less than half a mile for the exchange, there used to be a test that one could do to discover the length of the line, I think it was 1Km.

I would welcome any suggestions as to how to proceed, this is driving me mad

[Steve]

It look like interference from somewhere,if it's still doing it on the test socket anything nearby that could be acting as a source of noise i.e PSU , transformers. If you've swapped out the filter any chance of similar with the Netgear.

[Najarak]

Thanks Steve.

I have now changed from the Netgear to a 2Wire 2700, connection speed down to 2784kbps but seems steady, so far . I will leave the 2Wire on overnight and see what happens. There are no PSUs or transformers near the Phone socket, I have not changed anything electrical in the house recently.

DSL      Down      Up
Current Rate:      2784 kbs      448 kbs
Max Rate:      6772 kbs      636 kbs
Current Connection:
Current Noise Margin:      26.0 dB      12.0 dB
Current Attenuation:      25.8 dB      16.0 dB
Current Output Power:      19.7 dBm      11.9 dBm

These are from the 2Wire "Management and Diagnostic Console" rather than from the BT bit!

[Najarak]

After trying everything, on Tuesday I rang Support, they had been monitoring my line since Monday and could see that it was erratic.

There was noise on the voice line and so Miriam arranged an engineer visit on Wednesday, the engineer found a voltage drop in a box in the pavement, cured it.

Now everything works fine. Superb service.

Stats from the 2Wire are:-

DSL      Down      Up
Current Rate:      7616 kbs      448 kbs
Max Rate:      7840 kbs      1032 kbs
Current Connection:
Current Noise Margin:      10.0 dB      24.0 dB
Current Attenuation:      26.2 dB      16.0 dB
Current Output Power:      19.7 dBm      11.9 dBm

[Steve]

Excellent 

[Ray]

Good news. 

[Glenn]

Good service indeed.

[Simon]

Thanks for the update.   

[g7pkf]

with attenuation like that i would get interleaving turned off (if it isnt already)

[Steve]

Well spotted