Re: Varying Noise Margin

In article <4395ba92$0$1457$ed2619ec@xxxxxxxxxxxxxxxxxxxxxxxxxx>, Kraftee <kraftee@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> writes
Tiscali Tim wrote: 
In an earlier contribution to this discussion,
Chris <nospam@[127.0.0.1]>  wrote:

I have been getting occasional ADSL loss of synchronisation and
varying noise margin figures.  I have tried everything I can think
of, including rewiring my extension with ethernet cable - and I'm
wondering if anyone can suggest anything else?

Situation:
* 5 km from exchange
* Pipex
* Netgear DG834 version 2 latest firmware
* Line loss 49

Noise margin is all over the place.
It doesn't seem to relate to anything in my house
(although there may be things I'm not yet aware of).
Sometimes connecting another computer to the router causes the SNR to
drop - but not always.

It is usually between about 6 and 17.
(But why should it vary?)

Sometimes the router loses synch continuously, dropping out and
re-connecting about once a minute.  When this happens, rebooting the
router usually helps.

BT have been very helpful and have given me the best available on the
E-side and on the D-side and my Line Loss has gone from 59 to 49.

Any ideas will be gratefully received and valued. 

Have you tried a different router and/or power supply for the router?

I don't know whether the problem I had affects Netgear kit, but my
3Com router won't work reliably with the switch-mode power supply
provided by 3Com - but is fine with a generic 3rd-party power supply.

Have you got any other kit (e.g. laptop computer) using a switch-mode
power supply, which could be injecting noise into the system?


Have found that Netgear isn't to accurate for SNR readings (latest
firmware 3.01.5) so the OP maybe chasing ghosts there.


My firmware is 3.01.25 ... just checked.

Have you (the
OP) tried removing the bell wire on the master/frontplate to see what
happens, generally your Loop attenuation will increase by a couple of
points but your SNR should be affected to a greater extent to the
positive, it should also be more stable as well.  Even though you may
have wired it all in cat5 cable, it still doesn't make any difference to
the bell wire being unbalanced & effectively it can become a long wire
aeriel. You don't require the bell wire as each filter will decouple the
ringing, if it is required by the phone at all


I am getting results which confuse me.
At first I connected to the MEP and got a really good SNR of 27.
That was with mains powered laptop plugged into MEP.

I left it on overnight and next morning it was 24 ... still good.

Then, before I did my extension re-wiring, I checked again ... and got 15.

That is an enormous difference!

Then I re-did my extension wiring - about 90 feet - with cat5 cable - with 4 wires connected:

PIN 2 - CAT5 cable White (blue)
PIN 3 - CAT5 cable Orange (white)
PIN 4 - CAT5 cable White (orange)
PIN 5 - CAT5 cable Blue (white)

Then I got - on the end of the extension - 22 - then 17 - 16 - 16 ...

Why should it be changing?
This is not making sense!
And why should it be better at the extension than at the MEP?

Later I got 11.

After a reboot of the router I got 17-16-16-16-17-17.

Later I got 6-6-6-6-6-9-9-9-9.

Later I got 12-12-12-12-12-12.

This afternoon it was 14-14-14-14-14-14.

Now it is 12-12-12-12-12.

I am at a loss for hypotheses.
Can you suggest what might be going on?
--
Chris
.

Relevant Pages

  • Re: Varying Noise Margin
    ... Noise margin is all over the place. ... Sometimes connecting another computer to the router causes the SNR ... OP) tried removing the bell wire on the master/frontplate to see what ...
    (uk.telecom.broadband)
  • Re: Varying Noise Margin
    ... I have tried everything I can think of, including rewiring my extension with ethernet cable - and I'm wondering if anyone can suggest anything else? ... Noise margin is all over the place. ... Sometimes connecting another computer to the router causes the SNR to ... OP) tried removing the bell wire on the master/frontplate to see what ...
    (uk.telecom.broadband)
  • Re: Varying Noise Margin
    ... >> Noise margin is all over the place. ... >> Sometimes connecting another computer to the router causes the SNR to ... OP) tried removing the bell wire on the master/frontplate to see what ...
    (uk.telecom.broadband)
  • Re: Varying Noise Margin
    ... I have tried everything I can think of, including rewiring my extension with ethernet cable - and I'm wondering if anyone can suggest anything else? ... Noise margin is all over the place. ... Sometimes connecting another computer to the router causes the SNR to ... My old Netgear 814 gave problems, which were cured by a different power ...
    (uk.telecom.broadband)
  • Varying Noise Margin
    ... I have been getting occasional ADSL loss of synchronisation and varying noise margin figures. ... I have tried everything I can think of, including rewiring my extension with ethernet cable - and I'm wondering if anyone can suggest anything else? ... Sometimes the router loses synch continuously, dropping out and re-connecting about once a minute. ...
    (uk.telecom.broadband)