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[GigabitEthernet]

But a loss of 2dB in one go? Is that normal? I must confess I don't know.

[les-70]

  I agree that that the bit loading  is very odd and I don't understand it.    I have often noticed that upstream bit loadings on vdsl bands look odd though. My upper two bands show about the same bit loading and don't match what you would expect at all.

 Your apparent drop in attenuation may just be due to the total drop of any bit loading in the higher frequency downstream band.  If you  look at the attenuation per band you can see the sudden change.

[GigabitEthernet]

  I agree that that the bit loading  is very odd and I don't understand it.    I have often noticed that upstream bit loadings on vdsl bands look odd though. My upper two bands show about the same bit loading and don't match what you would expect at all.

First of all, I would like to say thank you as this is definitely making it easier for me to understand what's going on here

The thing that is strange about my line is that if you take a look at some (but not all) similar attenuated lines, if they do show most of the bits for the upstream, the upstream sync is still very similar to my line.

But I am only using half of the available tones...

[NewtronStar]

Indeed have had a look at your attenuation is has dropped by 2dB that is odd and very uncommon you my see 0.1dB + & - during a resync of modem.

Maybe a long modem power off period for 8 hours could help here and if you have still a BTOR visit booked from monday then i would do as much as you can internally and tick the boxes.

[GigabitEthernet]

I cannot really turn off the modem for too long - the family want to use the Internet all the time

[NewtronStar]

I cannot really turn off the modem for too long - the family want to use the Internet all the time

they all must need to go to bed at some time ! 3am to 11am just tell them the broadband line is down and curse your ISP   

[GigabitEthernet]

I don't think they'd believe me I'm afraid

I might be able to make it to four hours tomorrow whilst everyone is out?

[NewtronStar]

I don't think they'd believe me I'm afraid

I might be able to make it to four hours tomorrow whilst everyone is out?

It's up to you sometimes the modem gets odd info and there is no way you moved say 130 meters closer to the cabinet as shown by your attenuation unless your in a caravan.

Or Just wait until monday for the OR engineer to survey your line

[GigabitEthernet]

I'm hoping this engineer might actually do some line repairs if I can convince him of the HR fault.

How does an overheard D-side change work? Am I right in saying that there will be multiple lines in the cable?

[NewtronStar]

How does an overheard D-side change work? Am I right in saying that there will be multiple lines in the cable?

In the words of manuel (Fawlty towers) "Hii knoow nooothing"

[les-70]

Your apparent drop in attenuation may just be due to the total drop of any bit loading in the higher frequency downstream band.  If you  look at the attenuation per band you can see the sudden change.

   Do look at the attenuation per band I mentioned before.  The attenuation on the used bands has not changed.  A value for the higher frequency has just vanished probably due to no bit loading. The overall attenuation is somehow based on all three values so the change is a change in bit loading and the calculation and in not in attenuation.

[Bald_Eagle1]

Regarding Winter/summer attenuation changes, take a look at the example from my connection from January.


I do see increased attenuation, lower attainable rates & lower sync speeds every summer.

Since I started logging my stats back in 2011, August has always shown the highest attenuation.



Also, remember that some stats such as QLN & Hlog only update when the connection retrains.
It is feasible that conditions can change fairly significantly between resyncs/retrains.


If SNR/SNRM have also reduced due to increased crosstalk and/or increased RFI (maybe increased 'skip' propagation etc.), it can effectively rule out any use of the next higher band altogether and/or only be able to use a few tones from it.

[Bald_Eagle1]

These attached examples demonstrate the loss of tones available for bitloading since G.INP was activated in March.

The reduction has been gradual though, in line with the attenuation increases from my previous message.

[les-70]

  Do look at the lines of Bald_eagle1, Steveh and nstar, they have exactly the same bit loadings as you do as do others with similar sync. I conclude that your cliff edges and bit loadings are normal for your sync.  Those lines also don't show attenuation for the D3 band with no bit loading so your change in attenuation must be just due due to the loss of your tiny bit loading in that band. 

 I really think your issue is just a noisy line.  If your line still passes all the tests a pair swap would be worthwhile and should help if there is real underlying fault.

[Bald_Eagle1]

Also see the increase in attenuation as depicted by my Hlog graphs from March & today.

There is currently no sign of anything at all in the D3 band.


Based on previous years stats, I expect things will gradually improve between September & February.