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Standard User The_storm
(newbie) Fri 22-Aug-14 01:08:03
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2 Mbps line with SNR 16 , what max speed it supports ?


[link to this post]
 
hi guys
i have a 2 Mbps DSl line with Attenuation 56 and Downstream SNR 16 and i want to upgrade it
What max speed it can support ?
If upgraded to 4 Mbps,What value of SNR will it be ? And will it work properly ?
Note : My neighbour( in the same Building ) have a new internet connection and the ISP told him that he can get the max speed supported by his line up to 8 Mbps .When i checked his router i found that he just have about 3 Mbps ADSL2+ connection with SNR 6 and Attenuation 56 (Attenuation is the same as mine )
I don't think that all copper lines here have he same quality though they are in the same district or even in the same house. Another neighbour have a 2Mbps line (same as mine ) but its SNR is much lower (about 4 ) as the copper quality differs greatly
Note 2 :The tool in this site tells that my distance from the exchange is about 4 km and that's true .it also tells that i can get 3.735 Mbps as max speed. Can i really get that speed ? what SNR will i get then ?
Administrator MrSaffron
(staff) Fri 22-Aug-14 07:45:17
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Re: 2 Mbps line with SNR 16 , what max speed it supports ?


[re: The_storm] [link to this post]
 
Http://www.coolwebhome.co.uk/calc gives you estimates for various target noise margins

2Mbps at that attenuation is poor this is because of high target noise margin. Which ISP?

The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User XRaySpeX
(eat-sleep-adslguide) Fri 22-Aug-14 16:01:19
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Re: 2 Mbps line with SNR 16 , what max speed it supports ?


[re: The_storm] [link to this post]
 
Do you mean you have a Fixed 2 Meg connection or that you just happen to be connecting at 2 Meg on some RADSL product?

Fixed speed products are very rare (non-existent) these days.

If the latter do you know whether it is using ADSL (G.DMT), ADSL2 or ADSL2+? Which ISP?

You should be able to get about 3.5 @ 6dB NM with a 56dB attn. on any of those.

For the most part the quality of the line will be reflected in the attn.

1999: Freeserve 48K Dial-Up => 2005: Wanadoo 1 Meg BB => 2007: Orange 2 Meg BB => 2008: Orange 8 Meg LLU => 2010: Orange 16 Meg LLU => 2011: Orange 20 Meg WBC


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Standard User The_storm
(newbie) Fri 22-Aug-14 21:10:43
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Re: 2 Mbps line with SNR 16 , what max speed it supports ?


[re: XRaySpeX] [link to this post]
 
In reply to a post by XRaySpeX:
Do you mean you have a Fixed 2 Meg connection or that you just happen to be connecting at 2 Meg on some RADSL product?

Fixed speed products are very rare (non-existent) these days.

If the latter do you know whether it is using ADSL (G.DMT), ADSL2 or ADSL2+? Which ISP?

You should be able to get about 3.5 @ 6dB NM with a 56dB attn. on any of those.

For the most part the quality of the line will be reflected in the attn.

I have a Fixed 2 Mbps speed.
I know it's too rare todays, But as i said i'm from Egypt and this is the speed that the government thinks it's too sufficient. You know this country's miserable Army ruined the whole infrastructure aside with corrupt businessmen.

So if i upgraded to the max speed supported by my line,i should get 3.5 @ 6dB NM with a 56 dB attn ?
With that NM will it work properly ?
Administrator MrSaffron
(staff) Fri 22-Aug-14 21:42:50
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Re: 2 Mbps line with SNR 16 , what max speed it supports ?


[re: The_storm] [link to this post]
 
Should do, as many millions manage to run with 6dB noise margins. All depends on the noise present in the AM radio bands that may or may not affect your ADSL signal.

The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User TheEulerID
(newbie) Fri 22-Aug-14 21:56:09
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Re: 2 Mbps line with SNR 16 , what max speed it supports ?


[re: The_storm] [link to this post]
 
The 16db is actually the SNR margin (or noise margin), not the SNR. It's actually the difference between the actual SNR and the SNR required to run at the line sync rate (in your case 2mbps). The margin actually provides for a "safety factor", so that a short term increase in noise level due to environmental factors will not cause the line to drop out. A common noise margin for a stable line is 6dB, but some ISPs will allow margins as low as 3dB. Conversely, on an unstable line the margin may be set much higher, but this is normally the sign that something isn't right. The 16dB noise margin you have is exceptionally high, and the problem is that extra margin of about 10dB is using up part of the SNR that can be used for data transfer,

I would expect a line with your 56dB attenuation to achieve about 5mbps with a 6dB noise margin.

If you have a line that drops out frequently, that may be why the noise margin has been set high in order to maintain some stability. That could be a line issue, or a problem with internal wiring being vulnerable to noise. However there is another possibility, and that is that you have a set sync speed. I've known this happen on some btinternet lines as an (accidental) historical carry over from days when 2mbps was a fixed rate and it has got "stuck". One clue is if the download sync speed is always absolutely identical every time the line is re-synced. If this is the case, then the ISP would have to check it.
Standard User RobertoS
(elder) Fri 22-Aug-14 22:23:41
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Re: 2 Mbps line with SNR 16 , what max speed it supports ?


[re: The_storm] [link to this post]
 
In reply to a post by The_storm:
But as i said i'm from Egypt and this is the speed that the government thinks it's too sufficient. You know this country's miserable Army ruined the whole infrastructure aside with corrupt businessmen.
I don't think you did say that, but that's by-the-by. Are you saying this is a connection in Egypt, or you came from Egypt and this is a UK connection?

My broadband basic info/help site - www.robertos.me.uk | Domains,site and mail hosting - Tsohost.
Connection - Plusnet UnLim Fibre (FTTC). Sync ~ 56.6/14.1Mbps @ 600m. - BQM

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Standard User XRaySpeX
(eat-sleep-adslguide) Fri 22-Aug-14 23:14:55
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Re: 2 Mbps line with SNR 16 , what max speed it supports ?


[re: TheEulerID] [link to this post]
 
In reply to a post by TheEulerID:
If you have a line that drops out frequently, that may be why the noise margin has been set high in order to maintain some stability.
No, the NM is that high cuz OP is running a Fixed 2 Meg product, as he had stated, and his line is well capable of over 2 Meg, so the NM has increased to take up the slack.

1999: Freeserve 48K Dial-Up => 2005: Wanadoo 1 Meg BB => 2007: Orange 2 Meg BB => 2008: Orange 8 Meg LLU => 2010: Orange 16 Meg LLU => 2011: Orange 20 Meg WBC
Standard User XRaySpeX
(eat-sleep-adslguide) Fri 22-Aug-14 23:19:43
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Re: 2 Mbps line with SNR 16 , what max speed it supports ?


[re: RobertoS] [link to this post]
 
OP is running in Egypt. He talks about his government & 'this country's miserable Army'.

1999: Freeserve 48K Dial-Up => 2005: Wanadoo 1 Meg BB => 2007: Orange 2 Meg BB => 2008: Orange 8 Meg LLU => 2010: Orange 16 Meg LLU => 2011: Orange 20 Meg WBC
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