DSL Noise margins

[Kryten]

Can I grab some comparison figures for noise margins?

Having a little connectiong difficulty recently, just seeing if it's related to our line which is fuzzy at the best of times
20/21db downstream margin and 6db up here.

 

[nath]

16.5/17 Up, 6.1 Down (Noise Margin)
20 Down, 9.2 Up (Line Attenuation)

I connect at between 18 and 19mbits. Lemme know if you need any more info.

 

[inactionman]

Downstream Rate: 18784 Kbps
Upstream Rate: 1300 Kbps
Downstream Margin: 7db
Upstream Margin: 7db
Downstream Line Attenuation: 25
Upstream Line Attenuation: 12
Downstream Transmit Power: 19
Upstream Transmit Power: 12

 

[nath]

Gah - you're connected 8kbps faster than me. UNACCEPTABLE!

 

[Deebs]

Nath, inactionman

3 words: "I HATE YOU"

 

[nath]

Haw. Fear my e-penis!

 

[Krazeh]

Nath, inactionman, are you both on Be*??

 

[nath]

I'm on UKOnline.

 

[inactionman]

Be. All I can say is that sometimes living in central london, 0.25 miles as the crow flies from the exchange is a bonus...

 

[Krazeh]

Ah, was gonna say the connection speed seemed a little low for Be* line with that attenuation

 

[nath]

You think I'd get faster on Be than on UKOnline?

 

[Kryten]

Cheers, helped quite a bit.
Mine's as followed, currently

DSL Status: Up
DSL Modulation Mode: ADSL2+
DSL Path Mode: INTERLEAVED
Downstream Rate: 7101 Kbps
Upstream Rate: 927 Kbps
Downstream Margin: 25 db
Upstream Margin: 6 db
Downstream Line Attenuation: 21
Upstream Line Attenuation: 9
Downstream Transmit Power: 0
Upstream Transmit Power: 0

Not looking too shabby then, just going to look to removing the bell wire from the wiring and probably get BT out to check the fuzzy line, even though they found nothing previously I suspect it's the wiring in the communal box down the bottom :|

 

[inactionman]

You think I'd get faster on Be than on UKOnline?

You may not be faster, but it's £18 a month. Which is rather cheap.

 

[Kryten]

just for note too, I'm on Be (via O2 Broadband) and it's really rather good, the only problem is this one due to noise on the internal line.

Definatley worth looking at if you're in the catchment area and have an o2 phone contract and even if you dont i think it's still rather well priced. Not sure on Be's direct pricing though.

 

[SheepCow]

Downstream Rate: 16,016 Kbps
Upstream Rate: 1,321 Kbps
Downstream Margin: 6.5 db
Upstream Margin: 7 db
Downstream Line Attenuation: 25.5
Upstream Line Attenuation: 13.0
Downstream Transmit Power: 18.5
Upstream Transmit Power: 12.0

 

[nath]

I'd definitely move - it's about 6 quid cheaper/month than I'm currently on. Thing is, I've bitched and moaned to get the techies at UKOnline to configure my line to squeeze 18-19mbit out of it. I'm totally paranoid that if I change provider I'll end up with something like 12mbit and have Be* say "Sorry, that's all your line is capable of". Very much stuck with an "ain't broke, don't fix it" mentality right now.

 

[Krazeh]

Well given your line attenuation i'd think you'd potentially get near to 24mbit on Be*, and they're very good when it comes to helpin your squeeze that little bit extra outa of your line. As is the community I mite add.

 

[Kryten]

Folks, a bit more help required

BT coming out tomorrow to have a look at my almost certianly faulty line, and I'd like to gather some logs for them. Got a great little app called RouterStats which will do just that for me, but I'm not sure which stat is which.

I need to tell it the: Tx and Rx noise (transmit and receive)
Tx and Rx sync.

Guessing, I imagine the "sync" refers to the connection rate?
Which of the below therefore refers to the noise, the margin or attenuation?
There's so many words and abbreviations thrown round like SNR (Signal to Noise Ratio) - and in that instance, why is a dB value a ratio? :|

Downstream Margin: 26 db
Upstream Margin: 6 db
Downstream Line Attenuation: 21
Upstream Line Attenuation: 9
Downstream Transmit Power: 0
Upstream Transmit Power: 0

 

[inactionman]

Tx noise would be the upstream margin, I think. So Rx would be downstream.

dB is a ratio as you need to know the signal to noise ratio for any singal, it's the only meaningful stat. You want to know how strong the signal is compared to the noise.

Signal measurement is on an exponential scale, base 10 I think, so for every increment of 10 it increases the signal strength is doubled.

 

[Kryten]

Oh, I see. So understanding that right, would mean that 10dB is actually a ratio along the lines of 10/100 ?

Edit, no, that'd be 1/10 wouldnt it...

 

[inactionman]

Looking at wikipedia, I'm wrong, for every +10 it's a factor of 10 increase.

 

[Kryten]

Grumble. Installed RouterStats, set it all up nicely and it hasn't disconnected or even dropped the margins since. The joys of Sods Law.

 

[old.user4556]

ADSL Link Downstream Upstream
Connection Speed 8189 kbps 1111 kbps
Line Attenuation 40 db 11.5 db
Noise Margin 4 db 6 db

That's with o2, i'm paying for 8 Mbits on an ADSL2+ LLU service. I could probably get about 12 Mbits per sec if I upped to the 16 Mbits service, but 8 is more than fast enough for me. £7.50 a month, can't complain. Very pleased with o2.

I might add that my router is plugged into the master BT socket, as the extension wiring in my flat is utter shite and kills the speed to about 5 Mbits.

 

[GReaper]

Uptime: 3 days, 14:52:45
DSL Type: G.992.5 annex A
Bandwidth (Up/Down) [kbps/kbps]: 1,325 / 19,222

Output Power (Up/Down) [dBm]: 12.0 / 18.5
Line Attenuation (Up/Down) [dB]: 15.0 / 27.5
SN Margin (Up/Down) [dB]: 6.5 / 7.0


Only got it about 3 weeks ago, so I'm quite pleased!

 

[Chilly]

every 3 decibels is a doubling in signal power.

 

[ford prefect]

I can only dream of a decent broadband speed. My local exchange is the better part of two miles away and is made out of Meccano and sticky tape and the positive thoughts of the 7,967 people who use it. I get a maximum speed of 1.5mbit, and it isn't due for an upgrade until the second quarter of 2011, so it matters not a witt which ISP I use, although that doesn't stop tiscali ringing me up offering me an 8mbit package that they can't give me at least once every quarter.

No cable here either.

 

[Starman]

ADSL Link  	Downstream  	Upstream
Connection Speed 	16379 kbps 	797 kbps
Line Attenuation 	15 db 	3.5 db
Noise Margin 	        12 db 	16 db

I'm connected at 16379 kbps but then thats what Sky currently cap at.