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What's your SNR MARGIN? Mine's 5.0 or 5.5

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What's your SNR MARGIN? Mine's 5.0 or 5.5

I ask because I am having yo-yo problems with my service. I have disconnected everything and set it up next to the master socket and this makes only a minor change - the Loop Att. goes from 28.5 to 29, the SNR margin remains low.

Looking at the SNR spectrum from my router everything seems to be above 20dB and some over 40dB except the odd sideband.

Speeds are not great but measured by the (inaccurate I know) PlusNet system they are around 4mbs.

It's just the line keeops dropping.

I have my syslog running. Any comments/advice/ideas gratefully received
8 REPLIES
Community Veteran
Posts: 14,469
Registered: 30-07-2007

What's your SNR MARGIN? Mine's 5.0 or 5.5

If you are on MaxDSL then a figure of 5 or 6dB for downstream SNR is perfectly normal as that is the min level the exchange will try and sync at. It just appears your ADSL equipment can't handle that low a SNR reliably.

Note: you are not on LLU as it has a min SNR of 12dB.

If you are not on MaxDSL then that low a figure may be a problem as anything below 10dB can cause connection problems.

Make sure all phone equipment is connected through a filter, this includes faxes, old 56K modems, sky boxes, DECT phones.

Try connecting direct to the masetr socket and see if things improve. Also try the test socket behind the lowe removable plate on the Master socket.
N/A

What's your SNR MARGIN? Mine's 5.0 or 5.5

Quote
If you are on MaxDSL then a figure of 5 or 6dB for downstream SNR is perfectly normal as that is the min level the exchange will try and sync at. It just appears your ADSL equipment can't handle that low a SNR reliably.

Note: you are not on LLU as it has a min SNR of 12dB.

If you are not on MaxDSL then that low a figure may be a problem as anything below 10dB can cause connection problems.

Make sure all phone equipment is connected through a filter, this includes faxes, old 56K modems, sky boxes, DECT phones.

Try connecting direct to the masetr socket and see if things improve. Also try the test socket behind the lowe removable plate on the Master socket.


Thanks for the response. I am a LONG time business user who until I was MaxDSL'd was a happy bunny. Since then chaos.

Yes - I do have filters. I did try things in the master socket without change as I said above. I have a Drayek Vigor 2600vg which whilst it is not top of the range is reasonable business kit.

I guess what you are saying is that the line is borderline?Huh
Community Veteran
Posts: 14,469
Registered: 30-07-2007

What's your SNR MARGIN? Mine's 5.0 or 5.5

It may well be and the router may not cope too well with that low a SNR (some are very good like the DG834 and others can't even cope at 10dB).

All I can suggest is raise a Question and ask for your SNR to be raised to 9dB and see if that helps. It willmean a lower sync rate but stability may be more important to you on a business line. Note: you may have fight for this so keep pestering.

PN may also want you to go down the broadband fault checker route first which is likely to delay and SNR changes by a few weeks.
aussiegtc
Grafter
Posts: 27
Registered: 08-08-2007

What's your SNR MARGIN? Mine's 5.0 or 5.5

You could also try the UK2 firmware for the Draytek kit. It apparently is only for use where you have line stability problems, but may help you out.

I'm not going down that route until BT have a look at the line though... my SNR wildly fluctuates so I'm sure there's something else at play here... I happily watch it go from 20 to 10 to 5 then back to 15... all in 5 minutes... Smiley
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What's your SNR MARGIN? Mine's 5.0 or 5.5

I have low SNR but a wide range.
At the moment my SNR is as below
   	Connection Status  	Connected

Upstream Rate (Kbps) 448
Downstream Rate (Kbps) 4736
US Margin 22
DS Margin 5
Modulation GDMT
LOS Errors 0
DS Line Attenuation 46
US Line Attenuation 60
Path Mode Fast Path


My speed remains pretty much solid only perhaps fluctuating once every week to two but only by a small amount.
My SNR range is 2 - 12 but for the most part hangs at around 5 - 7.
If your router cuts off a fair bit then have you tried a different make. I found my Netgear DG834GT to be very sensitive and it was forever retraining the line. My D-Link G604T on the other hand holds a rock solid connection and causes little problems.

Regards,
N/A

What's your SNR MARGIN? Mine's 5.0 or 5.5

Quote
I did try things in the master socket without change as I said above.


Yes, but did you try the connection *behind* the master socket? Undo the screws and remove the bottom panel. There should be a socket to your right.
aussiegtc
Grafter
Posts: 27
Registered: 08-08-2007

What's your SNR MARGIN? Mine's 5.0 or 5.5

Good point - I tried that and found I synched at DOUBLE the speed...

Pity my master socket is in an airing cupboard (damn these flats!)...

Cry
N/A

What's your SNR MARGIN? Mine's 5.0 or 5.5

Hi

I am connected to the master socket and my snr figures are downstream 18
upstream 23
the Downstream line attenuation is 8db and upstream 4db
the xchange is at the bottom of the road but I only sync at 7616 is this normal

Cheers Martin