Deteriorating Noise Margin

Pickers · 11 Jan 2006 at 17:20

Just posted this in bulldog's forums - wondered if anyone here may have some advice:

My internet connection has become very bad recently, and Ive just checked my noise margin vales (which were low at 11 dB to start with), and they have dropped to a noise margin of 6.5 to 7dB!!

I have removed the face plate of the main socket in our flat (we only have one) and plugged the router straight into the one inside. The values dont improve

.
What can be done? Its getting really daft now, its been alright for a year and a half - but now its terrible

. My speeds have been comparable to 512 for the past few days now, despite being on an 8 meg contract.

What can I expect? Further deterioration? A solution perhaps?

Pickers · 12 Jan 2006 at 12:25

No one has any advice?

juno_first · 12 Jan 2006 at 17:03

I just got connected & have a dg384gt .32 bios
My noise level is 55db and varience is 9db & I am connecting at 3.5mbits / downloading >300kb/sec.
I should be getting 12.5mbits on adsl2 & am currently in a process of uko checking my line at the exchange due to the noise being >45db

mi9tchy · 13 Jan 2006 at 01:33

i've got bulldog 8mb and i'm synced at the max my s/n ratio is now at 6-7 it used to be 10-11, and doesnt make a difference to the speed i download at. but you could be getting lots of errors

juno_first · 13 Jan 2006 at 02:55

currently:
Connection Speed 3424 kbps 766 kbps
Line Attenuation 55.0 db 33.8 db
Noise Margin 11.0 db 9.9 db

It seams to vary but getting no errors that I know of.
uko maybe messing with my line at the moment as they say they will line check me as I am too noisy for 12.5mbits as promised, doh.

What figures are other people getting on adsl1 or 2

Pickers · 14 Jan 2006 at 07:41

I'm synched at 3Mbs and get a lot of errors :S

Fast Path CRC Error
near end: 26806 <-- going up by about 50 a second
far end: 12

Fast Path HEC Error
near end: 4938
far end: 4938
both going up by 10ish a second

that mean anything to anyone? Thats from this morning.

LOL a speedtest gave my downstream connection as slower than my upstream

I'm slowly reverting back to 56kps modem speeds. NOOOOOOOOO

Xee · 14 Jan 2006 at 14:37

Pickers said:
I'm synched at 3Mbs and get a lot of errors :S

Fast Path CRC Error
near end: 26806 <-- going up by about 50 a second
far end: 12

Fast Path HEC Error
near end: 4938
far end: 4938
both going up by 10ish a second

that mean anything to anyone? Thats from this morning.

LOL a speedtest gave my downstream connection as slower than my upstream I'm slowly reverting back to 56kps modem speeds. NOOOOOOOOO

Can you not phone Bulldog up, and ask them to switch you over to interleaved instead of fastpath? This should give you a more stable connection (but with slightly higher pings).

tolien · 14 Jan 2006 at 15:07

Turning up the target SNR would have a similar effect (less errors, more stability, reduced sync rate), and it's claimed they're willing to do that.
Usual master socket script wouldn't be amiss either.

Pickers · 14 Jan 2006 at 15:14

I spoke to them this morning, and they said they would make some changes to hopefully make the line more stable. Not noticed anything yet, noise margin still the same and the errors are still racking up just the same. Dont know when they were perform these changes - I was under the impression it was fairly immediate :confused:

benjo plz. · 14 Jan 2006 at 15:14

You noise margin is 7?! It needs to be atleast 12 tbh.

Goto SamKnows and check your line length.

tolien · 14 Jan 2006 at 15:18

Phnom_Penh said:
Goto SamKnows and check your line length.

It's straight line, so not particularly useful.
Time will tell when Bullfrog can be bothered making changes.

benjo plz. · 14 Jan 2006 at 15:22

tolien said:
It's straight line, so not particularly useful.
Time will tell when Bullfrog can be bothered making changes.

True, but it will still give a general idea. If it says hes a k or two from the exchange, it obvious he's going to have problems, if he's right next door to it, something else is causing foul play, and could potentially be sorted.

tolien · 14 Jan 2006 at 15:28

Phnom_Penh said:
True, but it will still give a general idea. If it says hes a k or two from the exchange, it obvious he's going to have problems, if he's right next door to it, something else is causing foul play, and could potentially be sorted.

If it says he's next to the exchange, the loop length could still be a couple of km, so you aren't really learning a lot

The rest of the stats (attenuation for a start) would be a much better measure.

benjo plz. · 14 Jan 2006 at 15:32

tolien said:
If it says he's next to the exchange, the loop length could still be a couple of km, so you aren't really learning a lot

True, but the point still stands if it says he's 1 or more K from the exchange

.

Pickers · 14 Jan 2006 at 15:34

Well It appears I'm not connected to the closest exchange, but the one I'm on is 1.4 Km away

tolien · 14 Jan 2006 at 15:37

Phnom_Penh said:
True, but the point still stands if it says he's 1 or more K from the exchange .

Could be another umpteen km on top of that though

At 1.4km, you'd expect an attenuation of about 10-20dB. Is it that?

Pickers · 14 Jan 2006 at 15:44

Up Stream 576 (Kbps.)
Down Stream 2720 (Kbps.)

Noise Margin:
16 dB Up
7 dB Down

Output Power:
11 dBm Up
20 dBm Down

Attenuation:
28.5 dB Up
46 dB Down

Indicator Name | Near End Indicator | Far End Indicator
Fast Path CRC Error | 13356 | 0
Fast Path HEC Error | 2496 | 2496

Statistics:
Received Superframes Fast 117892
Transmitted Superframes Fast 18678

benjo plz. · 14 Jan 2006 at 15:50

Pickers said:
Attenuation:
28.5 dB Up
46 dB Down

looks a bit high to me.

Pickers said:
Noise Margin:
16 dB Up
7 dB Down

looks low.

Pickers · 14 Jan 2006 at 15:54

/me looks: upset

tolien · 14 Jan 2006 at 15:57

46dB would seem to imply somewhere in the realms of 5km of cable, assuming it's ordinary copper with no dodgy joints etc.
First path should be getting Bulldog to up the target SNR margin (if that's not what they're doing), then take it from there.