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SNR tweaking? - Billion 8800NL

Community Veteran
Posts: 3,186
Thanks: 20
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Registered: 31-07-2007

SNR tweaking? - Billion 8800NL

I finally replaced my technicolor with the Billion 8800NL mainly as it has good reviews and it has SNR tweaking.  Historically my connection suffers when it goes below 6, so I wanted it fixed at 6.
So is the SNR figure I see from the statistics page the true SNR I am getting? or what DLM is trying to give me so I just ignore it as the router is over ruling it.  I have set it to 6, but it is still going as low as 3 too 4 during late evening and early morning going by the statistics page.
Unvalued customer since 2001 funding cheap internet for others / DSL/Fibre house move 24 month regrade from 8th May 2017
7 REPLIES
Superuser
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Registered: 22-08-2007

Re: SNR tweaking? - Billion 8800NL

Gus,
All you can do is "challenge" the target set by the DLM at the time of synching up.
That will give you the best synch speed which delivers the target MARGIN over the then back ground noise.
The fact that later on the SNRM is falling is indicative that you are suffering from REIN - electrical interference.  A drop of 1.5 to 2dB after dusk can be characteristic of night time AM (MW) radio transmission interference.  However I rarely see more than 0.5dB.
If one were to apply your logic - the set SNRM should never shift, then as the background noise rises, xDSL would need to be dropped to adjust the synch rate to maintain the signal margin over the noise.
The REIN could be from other sources like faulty electrical equipment.  RouterStats is a useful tool for monitoring that.  Generally manipulating the SNRM is not helpful.  If you want the fastest practical speed and stability you need to confirm what is shifting the SNRM.
Kevin
Community Veteran
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Registered: 31-07-2007

Re: SNR tweaking? - Billion 8800NL

Townman I assumed that the router did tweaking on the fly to get a SNR of 6, I learnt something today then. So to counter the drop in SNR would it help to resync after 8pm when the SNR starts to drop?  So to force it at 6 then or just stick to daylight resyncs as I do now if I get problems.
As for the rein I am guessing the street lighting, as I have them out front and back which both are within about 10 yards of my router
Unvalued customer since 2001 funding cheap internet for others / DSL/Fibre house move 24 month regrade from 8th May 2017
Superuser
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Registered: 22-08-2007

Re: SNR tweaking? - Billion 8800NL

Gus,
No, dynamic management of the SNRM would require (synch) rate adaptation which BT do not offer.
Personally I would synch in the ideal circumstances (a bright dry morning) run router stats and see where SNRM goes.  If the drops are too much to maintain stability, then indeed resynch in the evening when the interference is worse to attain a stable connection.  Then concentrate on running and monitoring router stats to see if you can see a correlation with anything.  Street lighting could be the cause, but it could also be something in your home which switches on (or changes it operation) in hours of darkness.
I once had the experience of a CCTV system which ran 24x7 so had not been considered a candidate for REIN.  When I had eliminated everything else - days of test switch off throughout the building (a pub) - and I unplugged this "it just cannot possibly be this" device only to see the REIN vanish.
The problem was that as darkness fell, RFI emitters on a number of the cameras kicked in an took the PSU outside of its stable operation profile.  Replaced the PSU with something more powerful and all was OK.
Kevin
JayG
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Re: SNR tweaking? - Billion 8800NL

For several years I ran my wired-only Netgear DG834 with the target SNRM tweaked from 3dB to 5dB via Routerstats, which seem to give the fastest possible connection whilst maintaining stability during the evenings, during which a drop of around at least 2dB I had come to regard as 'normal'.
Having bought a tablet device I needed Wifi, so PN kindly  Roll eyes sent me a TG582n - if it's tweakable I don't know how to do it, so I now have to rely on the DLM to get it right.
Again the original target was 3dB, but during the first evening the actual figure dropped to near or even slightly below zero, resulting in a resynch with a new target of 6dB. This lasted for a couple of days, but is now back to 3dB, at which it has held connection for 2 days at the moment, but is clearly on a wing and a prayer every evening.
Gus - your connection sounds as if it has similar properties to mine - if I could tweak mine I would - the DLM is making me nervous!    Cheesy
Twills
Grafter
Posts: 46
Registered: 14-05-2014

Re: SNR tweaking? - Billion 8800NL

I am currently working on my personal line regarding this matter and proven the issue is the new AMAZING LED lighting here in sunny Sheffield. My SNR target was 6 but the second the lights switch on it dips to between 2.5 and 3dB. Unfortunately my line is pretty long with a sync of only 5500Kbps at best but I found the only way to counter this was to raise the target to 9dB so the drop only leads to 6dB during the REIN issue. I have a REIN filter installed by OR engineer which made some difference and reduced some of the packet loss but that's all. If your sync is pretty good and you prefer stability over speed would you be happy to raise the target to 9dB at the loss of around 400-800Kbps sync?
Just a suggestion from my own experience,
Twills.
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Re: SNR tweaking? - Billion 8800NL

Twills that would be last resort, I am trying to keep my speed around 5mbit so I can watch TwitchTV at Source/HD quality.  Loosing that much speed would drop it below the speed required when caching would start, which makes watching live streams a pain.
My historical problem is that when it hits 3 then I start getting CRC's and DLM kicks in.  So a better router was the first fix and I will try tweaking the SNR higher to keep 5mbit.  Fibre would be the complete fix but I can't afford it this year after buying the router.  So I will wait and see if this router helps.
Unvalued customer since 2001 funding cheap internet for others / DSL/Fibre house move 24 month regrade from 8th May 2017
Twills
Grafter
Posts: 46
Registered: 14-05-2014

Re: SNR tweaking? - Billion 8800NL

Fair enough, just my 2 penneth Smiley Not had a problem watching HD on twitch with a 4Mb line maybe its worth exploring as it doesn't cost anything but completely your call. Just wanted to add what I've been doing with my line.
Twills.