SNR and speed - I am struggling here

[newboyuk]

I have a Billion 7800 DXL - firmware 2.32b

I have read the forums (not all obviously!) and am struggling with setting my SNR for max download speed.

Currently SNR setting via Config/WAN/SNR is at 1
========
xDSL
Mode ADSL_2plus
Traffic Type ATM
Status Up
Link Power State L0
Downstream Upstream
Line Coding (Trellis) On On
SNR Margin (dB) 9.6 6.4
Attenuation (dB) 26.0 17.1
Output Power (dBm) 0.0 12.6
Attainable Rate (Kbps) 23284 1180
Rate (Kbps) 9726 1178

======================

Now I read that as my max possible rate (attainable, on a good day etc) is 23k but I am getting 9.7k
No matter how I change the SNR setting (I have tried 6,5,4,3,2,1) and apply, no change in rate of 9.7k or SNR Margins (other than maybe 0.1)

My upload seems at max rate - what am I doing wrong here?
Thanks

[ranborne]

Try using the following as an SNR entry, until your superframe error rate is between 0 and 1%

4091
4090
4089
4088

[ranborne]

Also check out the snr table in this thread

viewtopic.php?f=18&t=2615#p8015

[newboyuk]

Couldn't connect with any of:
4091
4090
4089
4088

Kept on going up and connected at 4097 - same speed again
xDSL
Mode ADSL_2plus
Traffic Type ATM
Status Up
Link Power State L0
Downstream Upstream
Line Coding (Trellis) On On
SNR Margin (dB) 9.6 6.3
Attenuation (dB) 26.0 17.1
Output Power (dBm) 0.0 12.6
Attainable Rate (Kbps) 23236 1164
Rate (Kbps) 9726 1162

[billion_fan]

Couldn't connect with any of:
4091
4090
4089
4088

Kept on going up and connected at 4097 - same speed again
xDSL
Mode ADSL_2plus
Traffic Type ATM
Status Up
Link Power State L0
Downstream Upstream
Line Coding (Trellis) On On
SNR Margin (dB) 9.6 6.3
Attenuation (dB) 26.0 17.1
Output Power (dBm) 0.0 12.6
Attainable Rate (Kbps) 23236 1164
Rate (Kbps) 9726 1162

Try setting the SNR value to 1, you should aim for a downstream SNR of 4db

[ranborne]

How long are you leaving the router to try and sync when you change values?
Sometimes my router makes a couple of attempts before it actually syncs .....

Also I know that you probably bought the router to tweak snr but have you got rid of as much noise as possible on the line?
Eg plugging into the test socket (or used a faceplate splitter) and using a shielded modem cable ?

The reason I ask is your upstream SNR at 6.3 looks like the limiting factor on your line, so you may be suffering from noise near your router.
Make sure you have got rid of as many sources of noise as possible then look at your upstream SNR see if it increases, then try tweaking your snr again.

[newboyuk]

How long are you leaving the router to try and sync when you change values?
Sometimes my router makes a couple of attempts before it actually syncs .....

hmm - only 5 mins - does it take longer?

[ranborne]

No 5 minutes should be plenty,

(I can't remember which screen it is .... possibly Status->Statistics->xDSL shows the modem trying to initialize and establish the link.)

In the absence of any better advice I'd still try and get your upstream SNR Margin up to a higher value than downstream then try and tweak the SNR again.

[newboyuk]

OK _ I will try what you said

thanks

No 5 minutes should be plenty,

(I can't remember which screen it is .... possibly Status->Statistics->xDSL shows the modem trying to initialize and establish the link.)

In the absence of any better advice I'd still try and get your upstream SNR Margin up to a higher value than downstream then try and tweak the SNR again.