cancel
Showing results for 
Search instead for 
Did you mean: 

Ideal SNR

FIXED
stattman-uk
Hooked
Posts: 6
Registered: ‎26-03-2021

Ideal SNR

Dear Forum,

 

I recently went with a Tp-Link W9970 Modem Router which seems a bit more sturdy and user friendly, however I have noticed the SNR rates and was wondering if there is an acceptable range?

Upstream is: 5.9

Downstream is: 12.1

 

I also noticed that the Line Connection had restarted: showing an uptime which inferred that the connection had restarted. I'm assuming this is normal, but I always understood VDSL2 / FTTC was an Always-On experience. 

 

Best Regards

Mark

 

 

13 REPLIES 13
Baldrick1
Seasoned Hero
Posts: 6,515
Thanks: 2,938
Fixes: 191
Registered: ‎30-06-2016

Re: Ideal SNR

@stattman-uk  Welcome to the forum

It depends very much on your line. If it’s good enough for you to get your your full contracted speed then you want it as high as possible. If you are further away from the FTTC cabinet the DLM will drop it until it gets to the best compromise between speed and errors that need correction. In this case there is an automatic end stop at 3dB.

 

MisterW
Superuser
Superuser
Posts: 9,685
Thanks: 2,542
Fixes: 188
Registered: ‎30-07-2007

Re: Ideal SNR

@stattman-uk in your case you are not synching at the maximum speed and therefore your snr is way too high.

In fact your synch speed of 27397 would indicate that your line is 'banded'. This could be due either to internal wiring or an external line fault. You first need to eliminate any internal wiring issue by connecting directly to the test socket behind the master socket faceplate.

Superusers are not staff, but they do have a direct line of communication into the business in order to raise issues, concerns and feedback from the community.

stattman-uk
Hooked
Posts: 6
Registered: ‎26-03-2021

Re: Ideal SNR

Yes my connection from the TP-Link modem/router is directly into the master socket via a micro-filter. Which has been like this for a week or so now.  Performance has generally been good but "stutters" now and then. 

MisterW
Superuser
Superuser
Posts: 9,685
Thanks: 2,542
Fixes: 188
Registered: ‎30-07-2007

Re: Ideal SNR

Yes my connection from the TP-Link modem/router is directly into the master socket via a micro-filter.

@stattman-uk to be clear, you need to remove the master socket faceplate and connect to the test socket behind it. Removing the faceplate will(should) disconnect any internal extension wiring and eliminate that as a possible cause.

Superusers are not staff, but they do have a direct line of communication into the business in order to raise issues, concerns and feedback from the community.

stattman-uk
Hooked
Posts: 6
Registered: ‎26-03-2021

Re: Ideal SNR

My mistake: to correct what I earlier wrote, the modem is indeed connected to the Test Socket (behind the fascia).  The numbers being reported don't really mean much, however I'm wondering if it would be worth me contacting PlusNet support? 

MisterW
Superuser
Superuser
Posts: 9,685
Thanks: 2,542
Fixes: 188
Registered: ‎30-07-2007

Re: Ideal SNR

No problem, I just wanted to make sure.

What does the BT Wholesale checker https://www.broadbandchecker.btwholesale.com say for Downstream Handback threshold ?

If your current 27Mb synch speed is below the Threshold then raise a speed fault at https://faults.plus.net . They should check for banding and either remove it or request an engineer to investigate

Superusers are not staff, but they do have a direct line of communication into the business in order to raise issues, concerns and feedback from the community.

stattman-uk
Hooked
Posts: 6
Registered: ‎26-03-2021

Re: Ideal SNR

Thanks for the link, this is really interesting information!

I've attached the screen (excluding my my home phone). 

So download threshold seems 22.4 (clean) 18 (impacted)

I've also included my PlusNet Service from the home page of my account:

  • Product: Unlimited Fibre
  • Estimated Download Range: 18 - 32Mbps
  • Estimated Upload Range: 4 - 6Mbps
  • Minimum Guaranteed Speed: 16.3Mbps
  • Current Line Speed (Download): 25.2Mbps

Would be interested to get your thoughts. 

Many Thanks.

MisterW
Superuser
Superuser
Posts: 9,685
Thanks: 2,542
Fixes: 188
Registered: ‎30-07-2007

Re: Ideal SNR

Fix

Your speeds are above the minimum guaranteed so Openreach are not going to accept any fault. 

TBH if you put your downstream attenuation as reported by the router into this calculator https://www.speedguide.net/dsl_speed_calc.php then you can see that your speeds are about right. It estimates your line length at about 1.3km to the cabinet   is that about right ?

The fact that the router thinks the atrainable speed is 50Mb is dubious to say the least, if that line length is correct 

 

Superusers are not staff, but they do have a direct line of communication into the business in order to raise issues, concerns and feedback from the community.

stattman-uk
Hooked
Posts: 6
Registered: ‎26-03-2021

Re: Ideal SNR

Interesting. It mentioned Stoneygate which is the next district along, so that does sound about right.  Thanks very much for the information. 

RealAleMadrid
Seasoned Champion
Posts: 1,547
Thanks: 692
Fixes: 36
Registered: ‎07-07-2009

Re: Ideal SNR

@MisterW I think you are being rather pessimistic, I would always expect a line to sync at or near the high estimate on the checker. As you said in an earlier post the line is banded. Sync speed is 27397 with an SNRM 12.1dB when it should 6 or less.

Edit: By the way that speed vs line length site is way off. I have full 80mbps sync with 15.2dB attenuation. That calculator says I should get about 33Mbps.🙄

@stattman-uk You need to contact support and try to convince them that the line is banded, and ask for a DLM reset which will remove the speed cap.  I see the max observed speed on the checker was 24.99Mbps on the 3rd of March which is also a banded speed so it has increased since then but could be a lot better.

MisterW
Superuser
Superuser
Posts: 9,685
Thanks: 2,542
Fixes: 188
Registered: ‎30-07-2007

Re: Ideal SNR

I think you are being rather pessimistic,

@RealAleMadrid true, I am!. Agreed , the line ought to perform better according to the router stats but getting Openreach to do something about the speed when it's above MGALS is not going to be easy. The attenuation vs speed calculator does seem off but then again VDSL attenuation calculation is not as simple as ADSL. It does correspond with the BT wholesale figures to some extent though.

If one of the help team sees this thread then they may well action a DLM reset but I'm not sure the normal CSC staff can do that without an engineer visit and, as I say, that could be tricky when the line is performing above MGALS.

Superusers are not staff, but they do have a direct line of communication into the business in order to raise issues, concerns and feedback from the community.

stattman-uk
Hooked
Posts: 6
Registered: ‎26-03-2021

Re: Ideal SNR

Hello and Thanks very much for the additional information. I've researched some of the terms to understand this a bit better. All things being equal, a reset would be good as we were experiencing drop-outs and performance issues the previous few weeks, which forced my hand to buy the TP-W9970 a few days ago.  (Plus Net couldn't pin anything down to the line per-se).

So since setting up the TP modem/router have improved but I do wonder if the performance issues had an effect on the line... Your suggestion makes sense.

 

If anyone from PlusNet Support is viewing this and can offer a reset that would be really appreciated. Otherwise I will raise a fault / ticket.

Another thought comes to mind (this may be a daft question): If I were ever to move Broadband provider in the future would that in itself cause the line to be reset? 

 

RealAleMadrid
Seasoned Champion
Posts: 1,547
Thanks: 692
Fixes: 36
Registered: ‎07-07-2009

Re: Ideal SNR

@stattman-uk  It's not guaranteed but changing to another provider normally does cause a DLM reset. However you want to get better speeds now so I would raise a fault as staff members are not showing up much on the forum.