Snr adjustment

Kylie13
Posts: 7
Joined: Mon Jan 16, 2012 1:33 pm

Snr adjustment

Post by Kylie13 » Fri Feb 20, 2015 12:46 pm

Can the snr be reduced by 1/2 db steps?
I have a reasonable stable connection if I reduce to 4.2 on a line with 59db attenuation 2900kbps. Bt sets it at 6.4.
When the line resets the snr drops to 2.8 which is great for speed but pages don't load. Do I need to clear the snr entry box to prevent this?

Tomken
Posts: 467
Joined: Tue Jul 26, 2011 10:31 am
Location: Co Durham

Re: Snr adjustment

Post by Tomken » Fri Feb 20, 2015 12:56 pm

You could try adjusting the Billion tweak values by 10 at a time to see what that gives you, but BT's Line Management tends to override SNR tweaks.

For the sake of stability see what putting -1 back in does for you.

billion_fan
Posts: 5272
Joined: Tue Jul 19, 2011 4:30 pm

Re: Snr adjustment

Post by billion_fan » Fri Feb 20, 2015 1:00 pm

Kylie13 wrote:Can the snr be reduced by 1/2 db steps?
I have a reasonable stable connection if I reduce to 4.2 on a line with 59db attenuation 2900kbps. Bt sets it at 6.4.
When the line resets the snr drops to 2.8 which is great for speed but pages don't load. Do I need to clear the snr entry box to prevent this?
You need to check if you are authenticated once the SNR change is made (internet LED on Green), then you can try to browse the internet or ping some sites eg bbc.co.uk or ping IP addresses eg 8.8.8.8 to check for internet connectivity

Kylie13
Posts: 7
Joined: Mon Jan 16, 2012 1:33 pm

Re: Snr adjustment

Post by Kylie13 » Fri Feb 20, 2015 10:56 pm

To get to 4.2 I have been entering 75 in the snr box and leaving it there, is leaving it there why when the line renews it drops to 3.2 ish (the 1.5 reduction that 75 gives). This is the only option left to give a small increase as I already have the filter faceplate fitted.

Tomken
Posts: 467
Joined: Tue Jul 26, 2011 10:31 am
Location: Co Durham

Re: Snr adjustment

Post by Tomken » Sat Feb 21, 2015 11:12 pm

Kylie13 wrote:To get to 4.2 I have been entering 75 in the snr box and leaving it there, is leaving it there why when the line renews it drops to 3.2 ish (the 1.5 reduction that 75 gives). This is the only option left to give a small increase as I already have the filter faceplate fitted.
It depends upon what time of day the disconnects occur.

I went through a phase where it would either lag or disconnect about 11pm.

At night there's more noise so the SNR Margin will decrease anyway, so you may not be leaving yourself much wriggle room when it does drop.

I don't have the tweak table to hand but try the tweak setting by adding or dropping it by 5 or 10 and then check the SNRM to see if it gets you a slight reduction or increase.

With a Downstream Attenuation of 59 I would think BT already have you on G.Dmt but you could log into the router and change the setting to just G.Dmt should the router be attempting to connect at ADSL2 or ADSL2+.

Setting the router to just G.Dmt can be beneficial on longer lines.

Kylie13
Posts: 7
Joined: Mon Jan 16, 2012 1:33 pm

Re: Snr adjustment

Post by Kylie13 » Mon Feb 23, 2015 7:42 am

Before my recent escapade with BT I had the router set for G.Dmt but its now connected with ASDL. It reset yesterday to 6.1 again! I probally will have to leave it for a while if I reset the line much more they will be putting a cap on the line. To cloud the picture, Open Reach just installed a new cabinet under the rural development scheme. My existing cabinet is 4.5 KM from me and the new one will be 2.4KM. IF BT changed my cabinet I might get a faster fibre connection although it would, if the signal reaches,be at the lower end of the scale however if it doesn't reach(as is the case now) I would be worse of because my friend lives close to the new site and on his ASDL he only has a 1/2mb connection.

Tomken
Posts: 467
Joined: Tue Jul 26, 2011 10:31 am
Location: Co Durham

Re: Snr adjustment

Post by Tomken » Mon Feb 23, 2015 11:15 am

I don't think anyone has had any joy in tweaking the SNRM when they are with BT because of the auto Line Management which keeps resetting it to what it considers the best profile for a stable connection.

With the cabinet closer to you, that should reduce your Downstream Attenuation and give you a better ADSL speed, so I'd hang slack on going for Fibre.

With Fibre the degradation is only on the distance from the cabinet to you, as well as the condition of the cable from the cabinet and you - and the Contention - how many other users will be taking up the Fibre option when it comes to your area.

What is your friend's current Downstream Attenuation as he isn't connected to the new cabinet yet - I should think being quite close to the new cabinet will give a marked improvement to his speeds - that's if they run new lines from the exchange to the cabinet.

Kylie13
Posts: 7
Joined: Mon Jan 16, 2012 1:33 pm

Re: Snr adjustment

Post by Kylie13 » Tue Mar 03, 2015 6:58 am

I thought that distance to cabinet was not important with asdl that it was distance to the exchange that was the determining factor. Is this not the case? This was why I thought I risked being worse off by changing cabinet.

Tomken
Posts: 467
Joined: Tue Jul 26, 2011 10:31 am
Location: Co Durham

Re: Snr adjustment

Post by Tomken » Fri Mar 06, 2015 12:16 am

Kylie13 wrote:I thought that distance to cabinet was not important with asdl that it was distance to the exchange that was the determining factor. Is this not the case? This was why I thought I risked being worse off by changing cabinet.
The distance or amount of cable between you and the exchange is the determining factor for ADSL, but if the cabinet has been moved closer to you then that should reduce the amount of cable between you and the exchange just as if they left the cabinet where it was and built a new exchange which was closer to you.

That was the point I was trying to make.

If they've rewired to the new cabinet yet, has there been any change in your Downstream Attenuation ?

Dividing this by 13.81 will give the approx. amount of cable between you and the exchange in kms

Kylie13
Posts: 7
Joined: Mon Jan 16, 2012 1:33 pm

Re: Snr adjustment

Post by Kylie13 » Sun Mar 08, 2015 7:58 am

Thanks I misunderstood "distance to exchange" not just from your post. They have rewired some homes to the new cabinet but not me(hopefully yet) In the area around me I can spot at least 10 new cabinets (unfortunately I appear to be smack bang in the middle of the two routes)and BT are digging up the roadway around the bottom of the town.

The attenuation is back to 6.2 - 5.9

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