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Can I Fix My Target SNR at 6db?

Community Veteran
Posts: 1,139
Thanks: 4
Registered: 20-07-2007

Can I Fix My Target SNR at 6db?

I’ve searched the Community Forums but there doesn’t seem to be a definitive answer on this.
At night my noise margin falls to 1 and sometimes 0db although my router a Netgear DG834G rarely drops my connection. During the day the noise margin is 3db. Is it possible to fix my target noise margin at 6db to give it some room to fall at night? Or given that my connection rarely drops, am I worrying about nothing?
Current line stats are:
ADSL Link             Downstream Upstream
Connection Speed 18285 kbps 1099 kbps
Line Attenuation       18 db          4.5 db
Noise Margin             1 db             6 db
Thanks – Bob
Edit - I should probably add that I’ve tried rebooting the rooter at night, (in fact I did it just before I posted), but that still doesn’t force the noise margin up.
22 REPLIES
Community Veteran
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Re: Can I Fix My Target SNR at 6db?

Quote from: bobboulby
Is it possible to fix my target noise margin at 6db to give it some room to fall at night?

I think Plusnet can do this on request.
Quote from: bobboulby
Or given that my connection rarely drops, am I worrying about nothing?

Yes, probably. 
My noise margin wanders down from 3dB during the day to around 1 dB at night without any apparent problem.  This does not cause any drops but if I restart the router at night I get back to a 3dB noise margin with a lower speed.  Then the noise margin wanders up to 5dB during the day. 
Community Veteran
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Re: Can I Fix My Target SNR at 6db?

Quote
Is it possible to fix my target noise margin at 6db to give it some room to fall at night?
It used to be possible using a trial system but that option was withdrawn and it is no longer possible
Plusnet Alumni (retired) orbrey
Plusnet Alumni (retired)
Posts: 10,540
Registered: 18-07-2007

Re: Can I Fix My Target SNR at 6db?

Hi there,
The options for an SNR reset on ADSL2+ does allow us to specify a target margin but that's in no way fixed unfortunately and can (and will) change after the reset is done.
JayG
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Re: Can I Fix My Target SNR at 6db?

Bobboulby: My connection behaves very much like yours in that the DLM persists in choosing a 3dB SNRM which drops to 1 or even slightly below in the evening which sends the error rate sky high, although it rarely actually drops the connection.
I run mine tweaked from 3 to 5 via Routerstats - it usually re-synchs at 7.6dB for some reason then in a couple of days settles down to around 5 (daytime) and rarely less than 3 (evening.)
The tweak doesn't survive a router reboot but that's not really a problem unless you switch it off every day (according to my plug-in energy monitor my Netgear DG834v4 uses a mere 4 watts although the wireless version could well be different.)
Community Veteran
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Re: Can I Fix My Target SNR at 6db?

Thanks for all the replies.
Quote from: JayG
I run mine tweaked from 3 to 5 via Routerstats - it usually re-synchs at 7.6dB for some reason then in a couple of days settles down to around 5

I've had a look at RouterStats but it just seems to be a monitoring tool. I can't see any options for setting the noise margin. Please could you point me in the right direction.
Bob
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Re: Can I Fix My Target SNR at 6db?

It only works on certain routers - not one which Plusnet supply
Community Veteran
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Re: Can I Fix My Target SNR at 6db?

Mine's a Netgear DG834G.
Bob
JayG
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Re: Can I Fix My Target SNR at 6db?

Quote from: bobboulby

I've had a look at RouterStats but it just seems to be a monitoring tool. I can't see any options for setting the noise margin. Please could you point me in the right direction.
Bob

Have a look here.
Your DG834G is definitely supported - tweaking noise margins is done after telnet-ing the router by clicking the "telnet router" button.  Wink
Community Veteran
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Re: Can I Fix My Target SNR at 6db?

It depends which version - as far as I remember it is only the v4 with the Broadcom chip which does
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Re: Can I Fix My Target SNR at 6db?

It works with my DG834PN (broadcom chipset).
Also, my internet connection runs fine at night with around 1dB reported noise margin, so that isn't bad per se.     
JayG
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Re: Can I Fix My Target SNR at 6db?

Should telnet OK with any DG834 router Jim according to this:
http://www.vwlowen.co.uk/internet/routerstatshelp/support/experimental.htm
Community Veteran
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Re: Can I Fix My Target SNR at 6db?

Thanks again, I'll have to have a proper read of this later. Mine's a v3 by the way.
Bob
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Re: Can I Fix My Target SNR at 6db?

We are not discussing telnet we are discussing fiddling with the default noise margin.
This is only possible with the Netgear with a Broadcom chipset
This is the chipset listing against version
• Netgear DG834         (TI AR7 chipset)
• Netgear DG834G v1 (TI AR7 chipset)
• Netgear DG834G v2 (TI AR7 chipset)
• Netgear DG834G v3 (TI AR7 chipset)
• Netgear DG834G v4 (Broadcom BCM6348 chipset)
• Netgear DG834G v5 (Conexant CX94610 chipset)
• Netgear DG834GT (Broadcom BCM6348 chipset)
• Netgear DG834PN (Broadcom BCM6348 chipset)
• Netgear DG834N (Broadcom BCM6358 chipset)
• Netgear DGN2000 (Broadcom BCM6348 chipset)
JayG
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Re: Can I Fix My Target SNR at 6db?

OK Jim - that distinction certainly wasn't obvious from the web pages I looked at (including the Routerstat author's website, although I did find the info eventually.)
Hopefully the OP does have a Broadcom router so will be able to "fiddle with" optimise his target SNRM.