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[S.Stephenson]

My 2nd lines performance has dropped quite a bit in the last week from 66 to 57, plusnet will be sending out an engineer for this soon in the meantime i'm just trying to see what problems there could be.

My equipment is fine, have done the whole filter in the test socket stuff as well as trying different modems etc.

As a few of you may be aware I have 2 VDSL lines,

S.Step is my BT line which has had interleaving applied and a high INP on the download, other than that all seems perfectly fine and when interleaving is removed and the DLM relents i'd expect it to drift back to 65mbit.

S.Step2 is my plusnet line which at first performed well at 66mbps with no g.inp and has since dropped down to 57mbps.

Usually I wouldn't be too bothered but as I had load of issues when the line was installed i'm following up on this and a few things that jump out to me currently the attenuation is 15.3 vs 14.2 on the BT line and the spikes on the QLN.

attached is the QLN

[roseway]

Don't forget that the QLN graph is just a snapshot of noise conditions at the time of the last sync, so you can't read too much into a few spikes. If they are always present after a resync then they have a lot more significance.

[S.Stephenson]

Don't forget that the QLN graph is just a snapshot of noise conditions at the time of the last sync, so you can't read too much into a few spikes. If they are always present after a resync then they have a lot more significance.

Unfortunately haven't monitored this line too much so the only point of reference I have is before I had any problems.

Differences I see are a large differences in the higher tones.

I will resync again after a while as I dont want DLM to bring down it's mighty hammer.

Edit: added QLN with no x-talk.

[S.Stephenson]

This post is just a compilation of the QLN plots I now have.

The peaks are visible in the most recent ones

IMG 1 - QLN before issues
IMG 2 - QLN With issues
IMG 3 - With issues example 2

Also what could cause line attenuation to be different( 14.2 vs 15.3) even when both lines are from the same pole.

[kitz]

I cant spot anything too unusual in any of them.   Theres a few crosstalk humps beginning and end of D2 and a few of EMI/RFI spikes, but nothing in your downstream that really makes me go hmmmm.

Just had a look at your hlog, which looks good.
Your SNRm hasn't been running long, but so far it looks fine.

I note your E/S shot into red though, so looks like a bit too long running and 0dB and I expect the DLM will take some action.

Its not unusual for different lines to have different lengths.  My own attenuation jumped slightly after a pair swap, so did my power and ultimately the SNR.  I think I lost a bit of downstream speed and 2dB on the upstream,  but to be honest I was so glad to get the fault fixed and a stable line again that I didnt care.
Its really difficult to calculate fttc attenuation to length and projected speeds, because there are so many variables such as crosstalk and PSD masks.

[S.Stephenson]

I just hope DLM is gentle with me 

Seems to just be a low quality pair then.

Seeing as Plusnet are sending out an engineer I might as well see what they can do, if anything the engineer will do a DLM reset that I might need after what I've done today.

[kitz]

heh I hope so too.   Looks like you are currently on Open profile.