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Message 1 of 12

Very Low Upload Noise Margin But Line Is Stable

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Hi there,

 

I've just come back off holiday and found that even though my line has been up for over 15 days, my upload noise margin seems to have dropped to a very low 2 - 3 dB. I presume if the line is stable then there's nothing to worry about here?

 

BT Home Hub 5 stats:

 

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Distinguished Sage
Distinguished Sage
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Message 2 of 12

Re: Very Low Upload Noise Margin But Line Is Stable

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as long as not dropping connection then I would just monitor  from the 45gb uploaded there does not appear to be a problemSmiley Wink



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Message 3 of 12

Re: Very Low Upload Noise Margin But Line Is Stable

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Haha, I was away from the Saturday before last till last night and there has only been light usage of the internet by friends whilst away so don't know where that 45GB is coming from! lol

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Guru
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Message 4 of 12

Re: Very Low Upload Noise Margin But Line Is Stable

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Mine remained stable like that for months.  It meant that I had a significantly faster upload speed that I would get from a resync.  If it does become unstable it will resync and you will lose speed but gain stability.

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Message 5 of 12

Re: Very Low Upload Noise Margin But Line Is Stable

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Really? Surely if the lower the upload noise margin then the lower the maximum upload data rate so it would resync at a lower speed?

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Guru
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Message 6 of 12

Re: Very Low Upload Noise Margin But Line Is Stable

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Surely if the lower the upload noise margin then the lower the maximum upload data rate so it would resync at a lower speed?

As I understand it, the 'maximum' upload rate  is really just the rate that would be achieved at 6db SNR given the current line conditions.  It will only resync if the errors get too high.

 

At connection time on 2 June I had an upstream max rate of 20693 and actual of 19999.

The actual remain constant (of course) with no resync, the max dropped slowly to 19764 on 1 Aug, then suddenly to 19103, and dipping as low as 18847.  The connection only broke when I unplugged the HG612 and plugged in an HH5, which gave a max and actual of 18955.

 

That said, my difference between max and actual was less extreme than William_Grimsley's, with my lowest SNR was 5.2.

 

Thu Aug 06 2015 12:28:00 GMT+0100 (GMT Summer Time)
ds_max_rate: 75384
ds_rate: 50000
ds_snr: 13.9
us_rate: 19999
us_max_rate: 18971
us_snr: 5.3
hours_up: 1570.388

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Message 7 of 12

Re: Very Low Upload Noise Margin But Line Is Stable

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Oh, I see. Maybe 3 dB is now my target SNR for my upstream, or should I say my line wants to have that target SNR.

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Guru
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Message 8 of 12

Re: Very Low Upload Noise Margin But Line Is Stable

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No, I think you are just getting away with it.  I bet if you diconnected and reconnected you would get a lower speed and back to around 6db snr.

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Message 9 of 12

Re: Very Low Upload Noise Margin But Line Is Stable

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Ah ok, what am I getting away with? lol

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Guru
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Message 10 of 12

Re: Very Low Upload Noise Margin But Line Is Stable

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You are getting away with having a faster speed than you 'ought' to have.  And long may it last; or even better the line improves so that you can have even better speeds.

 

(Not sure what else you might be getting away with of course, but that is outside this forum .....)