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[S.Stephenson]

I have noticed occasional large spikes of high noise margin, would i be correct in the assumption that this is due to a source of cross-talk going offline?

S.Step on mydslwebstats at around 00:42 on the 10th of February.

Have attached the SNR around that time.

[William Grimsley]

I doubt it's to do with crosstalk, but it could be something electrical turning on in the night but this would normally cause the noise margin to decrease not increase.

[S.Stephenson]

Just had a closer look at attainable and such, if only it stayed that way 

[roseway]

It's interesting that the upstream and downstream SNRM values increased by the same amount (~5 dB). This is rather a lot for a single crosstalk disturber, so I would hazard a guess that there's some local source of wideband interference which is switched off and restarted periodically.

[S.Stephenson]

It's interesting that the upstream and downstream SNRM values increased by the same amount (~5 dB). This is rather a lot for a single crosstalk disturber, so I would hazard a guess that there's some local source of wideband interference which is switched off and restarted periodically.

Well my line is underground for all but ~30m, so what could cause that much interference?

The only thing I can think of off the top of my head is that a Substation is close, as the attached image shows, but surely BT thought about what affects it could have....

[Starman]

Unable to confirm because its an indoor substation but some secondary substations sites do have remote monitoring and automation for switching of the HV network.

It is possible its that although ours (depends on the DNO - unable to see the label on the doors) runs on a PAKNET system offered by Vodafone which I believe runs at 174MHz.

Are the times of noise fairly consistence or random?

[underzone]

Just to clarify, a high signal to noise (SNR) margin is good. So for 2-4 mins your line get MUCH better at 00:42. So you need to think what gets turned OFF at 00:42 for 2-4 mins. That will be the cause of the otherwise constant interference.

[S.Stephenson]

Unable to confirm because its an indoor substation but some secondary substations sites do have remote monitoring and automation for switching of the HV network.

It is possible its that although ours (depends on the DNO - unable to see the label on the doors) runs on a PAKNET system offered by Vodafone which I believe runs at 174MHz.

Are the times of noise fairly consistence or random?

It's always been for only 2-5 mins, how would I go about checking if it is a PAKNET system?

Does a PAKNET system cause noise that could cause this?

[S.Stephenson]

Just to clarify, a high signal to noise (SNR) margin is good. So for 2-4 mins your line get MUCH better at 00:42. So you need to think what gets turned OFF at 00:42 for 2-4 mins. That will be the cause of the otherwise constant interference.

Hell whatever it is I want it off  even if it means I have to go without power 

[kitz]

5db does seem a lot for just one crosstalker, but I have seen some crosstalkers take several dbs.

Most of mine are about 1dB, although I did lose one big chunk of speed from one in particular, I cant recall the SNRm value.   I tend to find both my upstream and downstream spikes are equal in value from crosstalk.

Out of interest I just checked about how much SNRm in total Ive lost compared to Aug 2013 and its

6.1db from my upstream (18.5 to 12.4) and
6.1db from my downstream (12.9 to 6.8)

I was surprised as I'd not noticed the upstream go down so much too, but then again my upstream is more erratic than my downstream.
My very early days were hard to tell though as I had an awful lot of spiking due to the fault on the line.

[S.Stephenson]

5db does seem a lot for just one crosstalker, but I have seen some crosstalkers take several dbs.

Most of mine are about 1dB, although I did lose one big chunk of speed from one in particular, I cant recall the SNRm value.   I tend to find both my upstream and downstream spikes are equal in value from crosstalk.

Out of interest I just checked about how much SNRm in total Ive lost compared to Aug 2013 and its

6.1db from my upstream (18.5 to 12.4) and
6.1db from my downstream (12.9 to 6.8)

I was surprised as I'd not noticed the upstream go down so much too, but then again my upstream is more erratic than my downstream.
My very early days were hard to tell though as I had an awful lot of spiking due to the fault on the line.

Well I know for a fact that I've lost ~20mb/s of actual DL sync http://www.speedtest.net/my-result/2960805637

I can remember when I first got the HH5A the attainable for DL was in the 95mbit/s range.

I've also had my attenuation drop from 16.3 to 14.2 due to having the line take a more direct route from the DP.

Hope if it is crosstalk the person who it is moves house, and a 90 year old woman moves in.
 

[NewtronStar]

It is a crosstalk disturbers modem being turned off and then on just wish they used the DLM 30 minute rule to get a retrain reason 0 rather than 1

I know who is my crosstalk disturber he is called Jim at premises no 5 and both of us notice an increase of DS SRMm by 4dB when one of us turn off our VDSL2 modem.

[kitz]

I know who is my crosstalk disturber he is called Jim at premises no 5 and both of us notice an increase of DS SRMm by 4dB when one of us turn off our VDSL2 modem.

I knew I had seen a couple of people who did have loss of several db through crosstalk but couldn't recall who.   Thanks for that confirmation.   I seem to recall seeing another 4-5 dB somewhere too.   It may have been aardvark or starman who about a year or so ago suddenly got a massive crosstalker? 

[kitz]

Well I know for a fact that I've lost ~20mb/s of actual DL sync http://www.speedtest.net/my-result/2960805637

I can remember when I first got the HH5A the attainable for DL was in the 95mbit/s range.

I've also had my attenuation drop from 16.3 to 14.2 due to having the line take a more direct route from the DP.

I think there's quite a few of us lost circa 20Mbps now - some even more - purely down to crosstalk

Hope if it is crosstalk the person who it is moves house, and a 90 year old woman moves in.

 

PS.. moving this thread as its more to do with fttc rather than monitoring software.

[S.Stephenson]

Another cross talker detected, just 1db stolen from me by this one 

If only I could have my own personal cable plant 

Well it all just goes to show that crosstalk varies wildly, one person may have a tiny effect whereas another may singlehandely take out like 1/5 of your speed.

All I can hope is that the crosstalk my connection causes avenges me 

Then again around 15% of the people on my cabinet are completely out of range of FTTC so I suppose it could be worse