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SNR / Attenuation

stubbyd
Newbie
Posts: 5
Registered: ‎05-12-2007

SNR / Attenuation

I'm looking for some advice here as to the best way forward (if any).
From where my router has always been my SNR and Attenuation readings are:
          Downstream              Up
SNR          12                        18
Atten        59                        31
The downstream attenuation figure can rise to 61 but I've never seen it higher
Anyway, I've just run a test from teh master socket using the BT test socket and got the following:
SNR    21      18
Atten  58      31

My basic understanding of this tells me that my internal wiring is OK but it may benefit from re-doing but if I use my router at my master socket with a dedicated NTE5 socket - would I gain any benefits?
I believe my line speed profile is locked by PN at present and I get a stable if pedestrian 1Mb.
Any suggestions - am I barking up teh wrong tree or just plain barking?
Ta.
17 REPLIES
James
Grafter
Posts: 21,036
Registered: ‎04-04-2007

Re: SNR / Attenuation

Hi there,
You're actually quite a way from the exchange, hence why your speeds aren't great.
I'd also be a little surprised about your noise margin being higher in the master socket.  I'd try rebooting the router a couple of times to se if this figure changes at all.
You *may* see an improvement from using a filtered faceplate as opposed to a filter.
Community Veteran
Posts: 26,720
Thanks: 934
Fixes: 10
Registered: ‎10-04-2007

Re: SNR / Attenuation

If the better margin is consistent and you are prone to disconnections you should see fewer if you use the master socket as there is more margin to play with.
jelv (a.k.a Spoon Whittler)
   Why I have left Plusnet (warning: long post!)   
Broadband: Andrews & Arnold Home::1 (FTTC 80/20)
Line rental: Pulse 8 Home Line Rental (£13/month)
Mobile: iD mobile (£4/month)
stubbyd
Newbie
Posts: 5
Registered: ‎05-12-2007

Re: SNR / Attenuation

Quote from: Jameseh
You're actually quite a way from the exchange, hence why your speeds aren't great.

Tell me about it! I'm also sat at the other end of an aluminium backbone running through the state as copper was in short supply when the estate was first built in the 70's/80's. This I believe also restricts data rates.
Quote
I'd also be a little surprised about your noise margin being higher in the master socket.  I'd try rebooting the router a couple of times to se if this figure changes at all.

Maybe I'm mis-understanding this aspect, but I thought that the higher the SNR figure then the better? I say this as my understanding is that for every 512kb boost in line speed it degrades/requires an additional 5/6db and I guess it is this I'm after being clarified
Also as you are a staff member, can you advise if my bb profile is locked and what I might need to do to "free" that up without the cost?
stubbyd
Newbie
Posts: 5
Registered: ‎05-12-2007

Re: SNR / Attenuation

Quote from: jelv
If the better margin is consistent and you are prone to disconnections you should see fewer if you use the master socket as there is more margin to play with.

Thanks for the reply - I don't get disconnections that often and the few times I do am more than happy just to power cycle my router to fix the issue.
James
Grafter
Posts: 21,036
Registered: ‎04-04-2007

Re: SNR / Attenuation

Stubbyd,
It's not actually a good thing for your SNR to rise on Max.  It is on the old fixed line products though.
For ever 3dB of SNR increase, you lose about 600-800Kbps in sync speed.
Your phoneline sounds... nice.
stubbyd
Newbie
Posts: 5
Registered: ‎05-12-2007

Re: SNR / Attenuation

Quote from: Jameseh
Stubbyd,
It's not actually a good thing for your SNR to rise on Max.  It is on the old fixed line products though.
For ever 3dB of SNR increase, you lose about 600-800Kbps in sync speed.
Your phoneline sounds... nice.


Ahh! Right - so I am mis-understanding it - thanks for the clarification. So in effect, I should stay with my router at the end of the extension.
Why does my phone line sound nice? Or you jesting about the aluminium stuff? As it happens, my MIL who doesn't live on the estate but is  a half a mile further away can get a maximum higher bandwidth than me - according to the tools. Perhaps I should move.
James
Grafter
Posts: 21,036
Registered: ‎04-04-2007

Re: SNR / Attenuation

Sorry, I was joking about the fact it was part aluminium.
Regarding the master socket, can you try a couple of reboots to see if the SNR changes?
If you're looking at moving house, see if there's any up for sale next to the exchange Wink
stubbyd
Newbie
Posts: 5
Registered: ‎05-12-2007

Re: SNR / Attenuation

Quote from: Jameseh
Sorry, I was joking about the fact it was part aluminium.
Regarding the master socket, can you try a couple of reboots to see if the SNR changes?
If you're looking at moving house, see if there's any up for sale next to the exchange Wink

OK - shall try some re-tests tomorrow if I find the time.
And I plan on not moving for a long time and certainly not next or even within 1km of my exchange - better speeds or not.
SamP
Grafter
Posts: 51
Registered: ‎02-08-2007

Re: SNR / Attenuation

Sorry to jump onto a 'stale' thread, but the original posters stats look very much like mine  I.E.
                        Down              Up
Atten               59.0             31.5
Margin               9.8             22.0
(Modem/router connected to test point in master skt.)
Fixed rate 1Mb service
My situation does differ from his in one important respect.  My house is 380 meters from the exchange!
As far as I understand it, although BT take money each month for allowing me to access broadband, they don't regard a phone line as faulty unless the sound quality on phone calls is poor - so they're taking money for a service that they won't support.
Is that correct?  Or can I actually get them to do something about these poor stats?
SamP
Community Veteran
Posts: 38,460
Thanks: 1,031
Fixes: 62
Registered: ‎15-06-2007

Re: SNR / Attenuation

It might be worth checking with your neighbours to see if their numbers are any better
A 59dB attenuation usually means that you are over 5km from the exchange
Jovetic
Grafter
Posts: 120
Registered: ‎17-12-2007

Re: SNR / Attenuation

A couple years back when i upgraded to 2meg at my old flat i started disconecting all the time, i got BT out and the guy came and checked thw wiring then went out to one fo those green boxes you see everywhere, aparently i was being run right around the entire estate before going back up town to the exchange "dont quote me on this" but he said he just rewired me at the box so i dont go all the way around and just back to the exchange.
SamP
Grafter
Posts: 51
Registered: ‎02-08-2007

Re: SNR / Attenuation

Quote from: Oldjim
It might be worth checking with your neighbours to see if their numbers are any better
A 59dB attenuation usually means that you are over 5km from the exchange

Good point. 
I'll try this approach, but of the two neighbours who would be most approachable, one is still on dial-up and the other fronts onto a different street & probably has a very different cable route to the exchange.
fransorci
Grafter
Posts: 34
Registered: ‎24-10-2007

Re: SNR / Attenuation

Here's my stats using my Netgear router, and I live about 500 metres from the exchange, as the crow flies.
So similar to you.
ADSL Link              Downstream      Upstream
Connection Speed 7072 kbps          448 kbps
Line Attenuation    19 db                  4.5 db
Noise Margin          14 db                  26 db

But obviously the cables in the ground don't go straight to the exchange.
Sounds like a possible fault with cabling, as my attenuation rates went up lots when I had a fault on the line (water dripping onto BT connection box and coroded connections).
oliverb
Grafter
Posts: 606
Registered: ‎02-08-2007

Re: SNR / Attenuation

Quote from: Jameseh
It's not actually a good thing for your SNR to rise on Max.  It is on the old fixed line products though.
For ever 3dB of SNR increase, you lose about 600-800Kbps in sync speed.

Took me a couple of minutes to figure what you meant there, on Max if the SNR gets better the speed comes up till the SNR is back where it was but you have higher speed, right?
Seems like the one thing that really messes with the Max service is a varying SNR such as the early morning bursts we used to experience.