SNR & Line Attenuation??

[Battery]

Please can someone explain this technical jargon to me...

My SNR is around 35.4 and the Line Attenuation is at a constant of 32.6...

Good, Bad? Just wanna know...

 

[KinsZA]

The higher the SNR the better
The lower the attenuation the better.

SNR is "signal to noise ratio" the higher this is the more stable you sync will be, as soon as this drops below 7 you have chance of sync loss, with my old adsl router my SNR was +-8 at 4mbit, if it dropped I would lose sync and sync speed. Rule of thumb is that you lose 5 SNR per megabit, so in otherwords you can basically stably have 4 more megabit than you currently have and still have a stable line.

Attenuation increases as distance from the exchange increases, I think at 60 you are classed as too far away from the exchange for adsl (I am at 54)

 

[Surv0]

SNR = Signal to noise ratio, the higher the value the better the signal, yours is pretty good
Attenuation = distance to the exchange, higher the value the further away you are. DSL can work up to about 60db but thats pushing it. Again your value is about average, it should cause you any problems...

 

[Scooby_Doo]

Is there a formula to work out SNR, router doesn't show it this is all i got.

DSL Status: UP
DSL Modulation Mode: GDMT
DSL Path Mode: FAST
Downstream Rate: 384 Kbps
Upstream Rate: 128 Kbps
Downstream Margin: 27 db
Upstream Margin: 21 db
Downstream Line Attenuation: 33
Upstream Line Attenuation: 20
Downstream Transmit Power: 0
Upstream Transmit Power: 0

 

[James]

Oh dear, I have SNR 21, and Attenuation 64

 

[Surv0]

hmm then maybe telkom allows for attenuation to be higher than 60... most international companies wont. The lengths Telkom will goto to sign people...

 

[ToSsMaStR]

how do i tell my own SNR and Attenuation?

 

[Scooby_Doo]

how do i tell my own SNR and Attenuation?

Your router should show it in the status page.

 

[Paul_S]

If you're using an ADSL modem plugged directly into your PC or you're using it in bridged mode there should be software that came with the modem that will give you all the info. Maybe even the default network details will contain it (I'm not an XP user so I'm not sure).

If it's an ADSL modem/router in non-bridged mode the info will be available on it (log in with a web browser as the admin user and check).

Paul

 

[Razer0]

An SNR or 10 or lower is crap. 20+ is fantastic.

Line attenuation: I think anything below 50 will be fine, but 50 is kind of pushing it...

 

[MrG]

Downstream Upstream
SNR Margin : 40.0 22.0 db
Line Attenuation : 17.0 8.5 db
Data Rate : 512 256 kbps

I should be able to upgrade to 4Mbit right?

 

[pip]

There is some interesting BT-related stuff on this at http://usertools.plus.net/tutorials/id/12

To get a reliable service your line needs to meet the following criteria:

1. 512K Service. There is now no upper limit and BT will attempt than make it work on any line if possible.

2. 1 Meg Services. You need a line loss of less than 60 dB, and so, typically, will be no more than 6.0 kilometres from the exchange.

3. 2 Meg Service. You need a line loss of less than 45 dB which means you will be 3.5 Kilometres or less from the exchange.

Also very important is the Signal to Noise Ratio. Remember that higher figures are better here.

I have not as yet found any article that determines the minimum Signal to Noise Ratio as acceptable for your ADSL to work correctly. However it is generally accepted that anything less than 10 -12 dB will cause problems and I would worry if my line had a figure of, say, 10dB and normally I would expect 15 dB or better.

 

[krycor]

SNR Margin & SNR are different i read somewhere..

 

[KinsZA]

An SNR or 10 or lower is crap. 20+ is fantastic.

Line attenuation: I think anything below 50 will be fine, but 50 is kind of pushing it...

I've never had any problems with my 54 attenuation, it was my low SNR that was giving me hassles, upgraded my router to a billion 7300g the SNR went up by 5 and havnt lost sync since.

 

[Wisemansa]

so if my router tells me this:

"ADSL Link Downstream --------Upstream
Connection Speed 640 kbps ----384 kbps
Line Attenuation 19.0 db--------10.0 db
Noise Margin 30.3 db-----------12.0 db "


then my SNR is 30.3?

 

[sybawoods]

I've never had any problems with my 54 attenuation, it was my low SNR that was giving me hassles, upgraded my router to a billion 7300g the SNR went up by 5 and havnt lost sync since.

Can a router really impact on these numbers...? Thought it was inherent to the actual line.

 

[Wisemansa]

Downstream Upstream
SNR Margin : 40.0 22.0 db
Line Attenuation : 17.0 8.5 db
Data Rate : 512 256 kbps

I should be able to upgrade to 4Mbit right?

ya i think so...cos my SNR is lower, and my line attenuation is higher, and i was told i am able to upgrade to 4mbps by telkom themselves, so you should have no problems...

just for safety send an email to telkom asking if your exchange supports it...(i recieved an answer in a day)....

EDIT: not a email a query thing on their website...fill it in and send it

 

[Nickste]

ADSL Link Downstream Upstream
Connection Speed 384 kbps 128 kbps
Line Attenuation 46.0 db 26.0 db
Noise Margin 28.7 db 15.0 db

4mbps possible for me?
Cheers, Nick

 

[sgs]

US Margin 20
DS Margin 21
DS Line Attenuation 63
US Line Attenuation 29

According to the 60dB forumula I shouldn't be online

Must add though that for me the attenuation varies significantly between various routers. My previous router (SMC) had better values around the 52 mark. My current Surecom reports various different values depending on its firmware version. (1st version = 54, next version = 49, currently version = 63)

 

[Wisemansa]

ADSL Link Downstream Upstream
Connection Speed 384 kbps 128 kbps
Line Attenuation 46.0 db 26.0 db
Noise Margin 28.7 db 15.0 db

4mbps possible for me?
Cheers, Nick

send telkom a query thing from their website....