cancel
Showing results for 
Search instead for 
Did you mean: 
clansman007
Contributor
13,737 Views
Message 1 of 47

SNR Margin on VDSL compared to SNR MArgin on ADSL

Hi

 

Newbie on this forum as I have recently swapped to BT for FTTC Infinity 2.

 

Quick question, would I be right in assuming that SNR margins work the same on a FTTC connection as it does on an ADSL connection in that SNR will have a slight drop as evening arrives but by morning we are back at a sustainable level

 

Reason I ask is that I see my noise margin drop steadily over the day from 6.5 to low 5s and then theVDSL drops. Spoke with 1st line support and was told that SNR doesn't matter as its fibre. Surely the copper from the cabinet to the home is where the SNR comes into effect hence I ask the people who know 🙂

 

Now I know that as night time arrives that a drop in SNR is normal and by morning it normally returns to its healthy state. Mine doesn't seem to. It just just steadily decreases until the VDSL drops, reconnects and does the same again. Might be a day, might be 2 or it might be multiple drops in a day

 

Just like the film Groundhog Day - if you have seen it Smiley Happy

 

Any advice is much appreciated

 

Thanks

0 Ratings
Reply
46 REPLIES 46
Sage
Sage
13,683 Views
Message 2 of 47

Re: SNR Margin on VDSL compared to SNR MArgin on ADSL

1st line support were wrong, target SNR is 6.0 and it's only fibre to the cab (FTTC). Try again tomorrow and post back if they still won't listen to you.

clansman007
Contributor
13,659 Views
Message 3 of 47

Re: SNR Margin on VDSL compared to SNR MArgin on ADSL

I didn't think it was right. Only ever had issues with ADSL lines and SNR margins but wasn't 100%

I have an open fault with them. Last week they said a change was made at exchange. My guess would be a software change and not a physical engineer change but it's not easy getting info. Whether the BT rep who called back new what was done I don't know

I have a call back due for Tuesday so I will let you know my findings

On another note, last year when I had fibre installed I was told by BT engineer that he could see a potential speed of 55Mb. Didn't matter at the time cos I opted for 40Mb. Since I switched it struggles to hold the 40Mb never mind anything greater

Thanks for the info - I will let you know how it goes
0 Ratings
Reply
Sage
Sage
13,612 Views
Message 4 of 47

Re: SNR Margin on VDSL compared to SNR MArgin on ADSL

Keep us updated as there is obviously an ingress of noise somewhere on your copper connection from the cab that needs seeing to.

 

Have you tried a quiet line test on your phone? If you can hear crackling the report it as a phone fault without mentioning BB.

clansman007
Contributor
13,595 Views
Message 5 of 47

Re: SNR Margin on VDSL compared to SNR MArgin on ADSL

Just did the quiet test, no crackles or other noises, just the gentle whoosh noise so no obvious signs of a line fault

 

Does that indicate a broadband only fault or could it still be a line fault

 

 

0 Ratings
Reply
Highlighted
Distinguished Expert
13,589 Views
Message 6 of 47

Re: SNR Margin on VDSL compared to SNR MArgin on ADSL

Which gentle whoosh noise? It should be silent....
--
To say thanks for a helpful answer, please click the white star
clansman007
Contributor
13,585 Views
Message 7 of 47

Re: SNR Margin on VDSL compared to SNR MArgin on ADSL

I would say a noise like the phone at the other end is up but no crackles or any other noise. Not describing it very well me thinks

0 Ratings
Reply
clansman007
Contributor
13,584 Views
Message 8 of 47

Re: SNR Margin on VDSL compared to SNR MArgin on ADSL

Just did it again with the mute on the handset and its quiet, no crackles or anything 🙂 Must have been the background noise from the room

0 Ratings
Reply
clansman007
Contributor
13,537 Views
Message 9 of 47

Re: SNR Margin on VDSL compared to SNR MArgin on ADSL

Just had a call from BT support. After going thru the same checks - for the 3rd or 4th time that I am in the Master Socket and not thru an extension, dont have any other devices plugged in and that I am using the BT faceplate as fitted by the BT engineer at Fibre install time

 

I am told that is perfectly acceptable for a FTTC/VDSL to drop up to 6 times a day. OK mines isnt dropping 6 times a day, as I said at the start, it may last 1 day without a drop but it might drop 2 or 3 times a day.

 

I monitor the SNR using Router Stats and I can see a steady drop in SNR from 6.5ish till under 5 till the VDSL drops, it will re-connect at just about the same speed till the SNR diminshes enough for it to fall

 

Am I missing something in saying that its not satisfactory that to raise a Broadband fault as there is no obvious noise on the line as per previous quiet test untill your VDSL drops more than 6 times a day

0 Ratings
Reply
Sage
Sage
13,527 Views
Message 10 of 47

Re: SNR Margin on VDSL compared to SNR MArgin on ADSL

If the SNR is acting in the way you describe then there must be some form of noise ingress to cause it. Just because it is outside of the audible range does not mean it doesn't exist.

 

What intrigues me is that it appears to be intermittant which could be difficut to track down.

 

That said I suggest you monitor your connection in your usual way over the next 24hrs but post the results here as well, if you use copy/paste to upload and get an HTML error ignore it and hit post again.

 

Meanwhile I'll flag this for a mod so use the contact link they let you have to send your account detail and a link to this thread.

 

Be aware it may take up to 5 days for them to reply once you have contacted them but they will be your one point of contact until the problem is resolved.