18db noise margin??

joll200x · Sep 25, 2009, 11:20:53

hey,

the latest chapter in my cr*ppy connection - my connection is showing 18db noise... i didn't think this was possible?

I'm pretty sure if IDnet / BT can request my noise margin to be reduced my line wouldn't be half as cr*p. Is this possible?
*****
   RF status

   Local   Remote
Tx Power   12.4 dB   20.5 dB
SNR Margin   18.0 dB   7.5 dB
Line Attenuation   53.0 dB   31.5 dB

*****

Rik · Sep 25, 2009, 11:32:31

An 18db margin probably reflects an overnight sync at the target of 15. During the day, the NM then increases as noise decreases. IDNet can request a margin reduction, but BT can refuse. If they do make the reduction manually, and then DLM kicks back in again, raising it back to a higher level, BT will usually refuse to reduce it a second time, so make sure you have done all you can to eliminate any local noise before contacting support.

joll200x · Sep 25, 2009, 16:33:55

all done to death i'm afraid. apparantly it was requested before but honestly I don't believe it was ever actioned. My logs never showed a change in either direction so not confident anyone will do anything...

Rik · Sep 25, 2009, 16:36:58

If the NM is changed, it forces a re-sync, so if your router logs resyncs, it should have shown (Netgears don't). Ask support, they will have a record if the margin was reset.

Rik · Sep 25, 2009, 16:55:03

I've asked support for you.

Your margin was reduced to 9db on September 4, and 6db on September 6. The line wasn't stable, so DLM kicked in and pushed the target NM back up to 15db. Essentially, your line is noisy and will only support 2M, BT will not reset the margin a third time. By contrast, I have a longer line than you, at 57db, but it's quiet enough to work with a 3db target NM, giving me a stable 4.8M sync, the margin fluctuating between 2.5db at night and 4.8db during the day.

joll200x · Sep 27, 2009, 12:27:56

thanks for that rik. At a bit of a loss as to what I can do now. I think I have another line coming into the house from looking at the wiring, does anyone know if BT will swap my circuit over or activate the other line (I figure I'll be paying for two lines then but don't have a great deal of choice).

Rik · Sep 27, 2009, 12:34:13

BT will swap the pair, but it might not improve things. Unless they can identify a fault, it's going to cost you in the region of £200 to find out. A better solution might be to get IDNet to put a new line in for you (they charge less than BT) as a sim provide. That will then mean it's installed by an ADSL engineer, rather than a voice one. Total cost is about the same as getting an engineer out, but with a greater chance of success. There's still no guarantee, though, unfortunately.

plugwash · Sep 27, 2009, 20:18:34

If you really want more speed and are prepeared to pay for it another option may be bonded or load balanced ADSL. It won't be cheap though.

ReDGryphoN · Sep 29, 2009, 08:22:34

Rik,

Could you expand on the the "new line" option you mention?

Exactly what bit of the line is run new from where to where?, Is is from the house to the CAB ?

Regards

ReD

KOFACME

Rik · Sep 29, 2009, 10:08:09

Hi Red

It's new from the exchange to the house. Whether any new cable is actually used is an unknown, BT do sometimes need to add extra copper to do the job, but usually they have spare pairs available, so it's just a case of 'joining the bits'. At the last hop, into the home, they may use an existing pair in the drop wire, or if that's not an option, they'll run a new cable in from the nearest distribution point, whether that's cabinet or pole.