ADSL SNR at 9db, declining speeds.

[#1]

Sorry to sound like a broken record.

My line is slowing down again but overall it's stable.
The SNR has jumped to 9db and won't reset to 6db, even with intervention from plusnet they have said their suppliers said there is no fault.

The line is syncing at 15800 kbps down and 980 up and the ping is all over the place.
This has been going on for a good few months, I've even bought a Draytek 130 modem a few days ago.

I know the line is within speed margins but I used to get full line speed and it was rock solid.
There must be a fault somewhere.

[#2]

@weeally46 

From my reading your previous complaint referred to a FTTC line, this looks to be a different ADSL connection.

What tests have you done yourself?

[#3]

Hi there, I've just been looking into this for you and diagnostic tests aren't showing signs of any obvious causes for the issue. Could you try following the checks here next please? https://www.plus.net/help/broadband/connection-troubleshooting/

Let me know how you get on

[#4]

Nope the same line it's ADSL.

Quiet line test.
Replaced the microfilter many times.
Changed and tested all cables to and from the modem.

[#5]

The SNR was running at 6db for months.

I'm running the line on a Draytek Vigor 2860.
The line used to be fast and stable, peaking at 20mbps.

If I apply an SNR tweak on my end and set it to -3db the line will sync higher and at 6db.

The line has never been the same since a new property was added to the exchange.

[#6]

The SNR is now sitting at 8db which is strange.

[#7]

Hiya @weeally46, I have now reset that back to 6dB for you but if it does increase again it may be worth us sending out an engineer to take a look at this for you. 

Can you let me know how you get on?

[#8]

@LaurenB Hi. Tthe line is syncing at 18737kbps and 1000kbps thats better and looks stable. Thank you.

[#9]

Hello @LaurenB there is a pretty agressive interleaving depth applied to the line.

[#10]

Thanks a lot for getting in touch @weeally46.

Your current broadband connection profile is WBC 160K - 24M Low delay (INP 0) 6dB Downstream, UC Medium delay (INP 2) 6dB Upstream (ADSL2+)

Prthaps the low / medium level of interleaving has been applied as the SNR margin has dipped below it's targer SNR of 6dB, which might be attributed to the few drops that we've seen in the recent days. Have a look at my tests though, speeds are still higher than those expected on BT's availability checker, and the only thing I've noted that might be a cause for concern is the MTBE. We could adjust the profile going forward to ensure DLM makes no positive changes to the profile should the MTBE hit 86400. 

Wanna give that a go?  

KBD

xDSL Status Check
Circuit ID:	CBUK74332965	Service ID:
Telephone NO.:	NA	Test Executed On:	12-07-2022 10:52:29

xDSL Status Test Summary
Sync Status:		Circuit In Sync
General Information
NTE Status:		NTE Power Status:	PowerOn	Bypass Status:

	Upstream DSL Link Information	Downstream DSL Link Information
Loop Loss:	2.4	2.5
SNR Margin:	6.7	5.4
Errored Seconds:	0	0
HEC Errors:	0
Cell Count:	0	0
Speed:	1000	18933

Maximum Stable Rate (KBPS):	18176	Fault Threshold Rate (KBPS):	14541
Mean Time Between Retrains (Seconds):	86400	Mean Time Between Errors Upstream (Seconds):	86400
Indicative Line Quality:	A	Mean Time Between Errors Downstream (Seconds):	686
Custom Thresholds
MTBR_RED:	MTBE_RED:
MTBR_GREEN:	MTBE_GREEN:

Radius

[#11]

If you have a Draytek router, you can change SNR yourself. You should only do it if you know what you're doing though, as you can easily make a mistake and this will in turn make your line unusable. 

https://www.draytek.com/support/knowledge-base/4800

Once you're happy with the SNR, you need to remember to save the configuration so that the router can always sync at that particular SNR. Otherwise, it'll sync higher if you have line problems or lower, after a period of stability.

[#12]

---

@weeally46 wrote:

Sorry to sound like a broken record.

My line is slowing down again but overall it's stable.
The SNR has jumped to 9db and won't reset to 6db, even with intervention from plusnet they have said their suppliers said there is no fault.

The line is syncing at 15800 kbps down and 980 up and the ping is all over the place.
This has been going on for a good few months, I've even bought a Draytek 130 modem a few days ago.

I know the line is within speed margins but I used to get full line speed and it was rock solid.
There must be a fault somewhere.

---

Just a thought: https://community.plus.net/t5/Broadband/Line-Banding/td-p/1852060

Have to see how it goes. 🙂

[#13]

Hello, @adam945 sorry for the late reply.

The SNR was dipping below 6db, the line has now synced at 9db and noticeably slower again.

[#14]

Then with your Draytek router force it back to 6dB. 

On a related matter: if you're line is unstable at 6dB, then there's an issue somewhere on the tel. line (either your property or Openreach's network) that needs resolved.