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[S.Stephenson]

If you lose 15% in one go it supposed to be investigated as a fault right?

[Chrysalis]

the upper range for crosstalk is circa 40% of a line's initial capacity  Even that is no guarantee.

In the beginning, (January 2016) I had an attainble of 116Mb/s down

40% loss would take you down to about 69mbit.

Lose 15mbit sync in one go? definitely not abnormal.  Happened to me TWICE.

You live in apartments high density of population, is logical crosstalk will be on the high end.

As far as openreach are concerned they will probably only be bothered if you are significantly below your estimated speed, or if the GEA test fails.  My line did fail the GEA test when it lost a ton of sync speed quickly as there is/was a rule where if you lose enough sync speed in  ashort period of time it will make the test fail.  Note we are talking about sync speed not attainable, so anything above 80 wont affect it.

[mlmclaren]

It don't seem right to me, I've pretty much watched everybodie's connections go on in this building, I was the first.... I have a feeling this is going to be something to do with the Kelly Comms visit yesterday.... the DP cabinet was left open too which I relocked upon arrival home last night...

Think I'll have to have a look inside and see if its been left in a mess again... 4 days after I was activated the 3rd connection was activated but for some reason the engineer decided to mess with the spair pairs which he found where not required... however he left them hanging out all over the place and when he replaced the DP's cover even left them hanging out the edges... that had a small affect on my SNR then (howver was still above 100mb then.

[burakkucat]

Has anyone taken a look at the QLN plot via MDWS? 

I tend to look at the Hlog plot first and then the QLN plot. In this case the Hlog is good but the QLN, although not showing significant peaks from RF ingress (originating from licensed broadcast transmitting stations), shows a greatly elevated noise floor and is overlaid with a fine "mush". 

My conclusion it that there is some defect in the physical infrastructure of the circuit.   

[burakkucat]

   Hmm . . .

I'm just guessing but I suspect that the AC balance for the pair may be very degraded. I wonder if there is a possibility of split legs in the pair?

(I wonder what Kitz or N*Star will make of that QLN plot?)

[S.Stephenson]

The shape seems strange to me but not the noise floor, see mine below which is heavily effected by crosstalk and then mlm's QLN.

[burakkucat]

I see what you mean but it is somewhat difficult to accurately compare the two plots, as the vertical axes are different -- different scales.

(Of the two, I would say that your QLN plot is the better.)

[Edited to replace the word Hlog with QLN.]

[roseway]

A note of caution about reading too much into the QLN graph: it's only a snapshot of noise conditions at the time of the last resync. It doesn't necessarily look anything like it would now if you forced a resync. An extreme example of this is when the sync occurs immediately after a power cut. That's what happened to me a few days ago, and look at my crazy QLN, which clearly doesn't represent conditions as they are now.

[konrado5]

mimclaren: could you attach your Hlog? Unfortunately I see only blank page, when I open https://www.mydslwebstats.co.uk/

Best regards
konrado5

[burakkucat]

Here it is K5 --

[NewtronStar]

A note of caution about reading too much into the QLN graph: it's only a snapshot of noise conditions at the time of the last resync.

That is exacly what I have found the QLN looks better during a daytime resync 8am to 4pm and the QLN looks worse during an evening resync 5pm to 2am resync of course it all depends if the users line is showing large SNRm swings

Here in this graph you can see the crosstalker in action

[Chrysalis]

Has anyone taken a look at the QLN plot via MDWS? 

I tend to look at the Hlog plot first and then the QLN plot. In this case the Hlog is good but the QLN, although not showing significant peaks from RF ingress (originating from licensed broadcast transmitting stations), shows a greatly elevated noise floor and is overlaid with a fine "mush". 

My conclusion it that there is some defect in the physical infrastructure of the circuit.   

I fear this reply will set him now on a warpath with openreach determined to get a fault fixed that doesnt exist.

QLN doesnt suggest a fault to me, what do you mean by raised noise floor?

[konrado5]

burakkucat: could you attach Hlog text data? I'd like to plot Hlog graphs for ADSL2+ band (first 511 tones).

[NewtronStar]

I have worked out your crosstalker has taken 13912 Kbps or 13.9Mbps away from your line sync that is a big chunk to lose to hell with G.INP we need Vectoring ASAP 

[kitz]

(I wonder what Kitz or N*Star will make of that QLN plot?)

I see signs of crosstalk in both the D1 and D2 bands. 
D1 is sometimes harder to judge because of PCB, but D2 has a few of the bumps that tend to be a give-away, and there's a nice big one at the end of D1.

The 'mush' is quite common on VDSL - take my own for example.

Based on an attenuation of 16.8dB, a sync speed of circa 65Mb seems about right
mlmclaren is possibly aware of it most if he was first on the cab and seeing that erosion occur as each new line gets attached. Its seldom anything over 14dB manages to keep hold of the full 80Mbps once the cab starts to fill.

Some may recall aardvarks line last year taking a massive hit from one cross-talker which took him down to about 65Mbps from 80Mbps and despite BT going out there was nothing they could do.  I know he fought for several months and PN tried to help at first, but iirc even with a new pair he never got the speed back and it was just put down to x-talk.  Ive just checked his current stats - Atten = 16.4dB and looks like he's banded at 60Mb.

These are my stats from the HG612 last year:
     
      Upstream   Downstream
Current Rate (Kbps)   20000   79999
Max Rate (Kbps)    30660    80924
SNR Margin (dB)      12.5   6.4
Line Attenuation (dB)   0   0
Power (dBm)      14.3   5.7

That doesnt show atten but according to the router Im using atm -  Attenuation:   11.4 dB           12.6 dB

Crosstalk is a bitch on VDSL and I can only agree with NS's comments about vectoring.