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[kitz]

I'm happy that I resolved the crux. Unfortunately the ISP tech staff probably didn't heared about PSD masks. I don't know if they change it.

I dont think they will.. its certainly not the sort of thing thats put in place lightly,  and its there for a reason.  To have put the mask in place will be there to protect many connections from being knocked out completely.

Looking at your QLN with that spike right in the centre would indicate to me there is still an amount of RFI getting through, therefore that tone would be useless.   How much it affects your neighbouring tones is anyones guess, as this would change from various localities.
 Because its been set on the dslam, it will affect everyone connected to it in your town.   So if they remove it, its possible that connections on say for example the other side of your town will start being troublesome.  That filter is possibly keeping a lot of other connections more stable.

[konrado5]

Looking at your QLN with that spike right in the centre would indicate to me there is still an amount of RFI getting through, therefore that tone would be useless.   How much it affects your neighbouring tones is anyones guess, as this would change from various localities.

It's hardly ever seen at my QLN. I've attached other QLN.

To have put the mask in place will be there to protect many connections from being knocked out completely.

I'm almost sure it is mistake. I suspect in Poland there are DSLAMs selled with default HAM PSD mask. My synchronization was lowered about 3 mbps when my ISP changed DSLAM. Moreover, someone in Poland has the same PSD masks and he uses other ISP service and lives 40-50 KM away from me. He got the gap suddenly and also lost 3 mbps.
http://obrazki.elektroda.pl/1012425200_1396541143.jpg

http://forum.kitz.co.uk/index.php?topic=13838.0

His ISP persists: it is implicited by lowering line quality because of time ( I don't know how to translate it. I think about: line quality is worse if the more time elapsed).

[GigabitEthernet]

[renluop]

<<snip>Digressing briefly on onto the subject of attenuation.
I have two different routers of slightly different make from the same manufacturer, The line Hlog curve reported by one is different from the Hlog reported by the other as is the overall quoted line attenuation figure by 2dB. The line does not change and I can swap the routers over back and fro and the reported attenuation changes with the routers.
This is not the line changing its characteristics, it the the calculation/measuring methods used by the different routers internal firmware that is resulting in different attenuation's being reported.<snip>

A bit OT but so many people  do not recognise how roundings and number of decimal places used in calculations can affect mathematical outcomes.

Yet in real life it makes not a jot of difference, so konrado, please get a real life.

and countess of Google "Więc proszę się prawdziwe życie"

[konrado5]

kitz: what do you think about my above replies?

[kitz]

I dont think I have anything else to say other than whats already been said.

-----

>>> it is implicited by lowering line quality because of time ( I don't know how to translate it. I think about: line quality is worse if the more time elapsed).

This is usually the effect of what we call crosstalk....  ie the more people that join the cab, then speeds get lower.   There isnt anything you can do about that..  Im sure Ive mentioned several times, that when I was 1st on a brand new shiny adsl2+ MSAN I could easily get 24/2.7 Mbps.   A few years later it was something like 21Mbps.   

If you read the VDSL sections you also see lots of us talking about it.   Those of us first on new DSLAMs are finding several months later that we are losing a heck of a lot of speed.    BE has lost circa 20Mb,  I lost nearly 20Mb in about 9 months.   BT is well aware of it, unfortunately the faster speeds mean we lose more    Its why we are waiting for a new technology called vectoring to come in as this lessens the effects of crosstalk.

[konrado5]

kitz:  I've meant that  someone (someone else who also has 410-477 gap) ISP says: 410-477 gap is caused by lowering line guality when time elapsed. I think it is not cause. I know there are crosstalks. I've noticed it when my ISP sometimes reboot DSLAM. Then I get about 1.5 Mbps higher synchronization rate.

[kitz]

>>> 410-477 gap is caused by lowering line guality when time elapsed.


I wouldnt think so...   too many other causes could do it.  Unless its x-talk or interference, then a line doesnt usually degrade in that way over time - its not something Ive seen before.

[konrado5]

Thank you for reply. 410-477 gap is explained. What do you think about strange phenomenon: there is always immediately after synchronization establishment: SNR margin 5.9 dB, power output 18.8 dBm, however some seconds after: 6.1 dB, power output 18.6 dBm. First strange thing is: there are always the same values. Second strange thing is: there are higher SNR margin when the power output is lower. Third strange thing is: the values are always changed few seconds after synchronization establishment. I don't know if it is typical or rather strange phenomenon on my line. I don't know if somebody checked it. It happens even if bitswap is off.

Thank you very much for your help
konrado5

[NewtronStar]

Hi Konrado5 sorry to but in you seem very knowleageable into the workings of Broadband, I have uploaded my tone Graph and you will see there are a number of tones missing would you be able to help me understand why they are missing.

Cheers NS

[konrado5]

NewtronStar: attach SNR per tone, QLN and Hlog. It seems it is radio interference or bridge tap.

[JGO]

Neutron Star's missing tones seem to correspond (well, more or less ) the  40m Amateur and Broadcast bands. Coupled with Konrado's similar blanking of the 160m band (more or less)  this supports the idea that these masks are to hide interference. There are better ways of doing this on an individual basis, but to the administrative mind this is unthinkable; IT MEANS ADMITTING THEIR SYSTEM ISN'T PREFECT !  ( Be grateful, in previous ages the suppression of dissidents could be quick and brutal. remember Galileo ! )     

 I think you are both stuck with it, in the interests of stability, (and think what sticks to your shoes in a stable !)
 

[konrado5]

. Coupled with Konrado's similar blanking of the 160m band (more or less)  this supports the idea that these masks are to hide interference

NewtronStar Hlog and QLN will determine it.

[NewtronStar]

. Coupled with Konrado's similar blanking of the 160m band (more or less)  this supports the idea that these masks are to hide interference

NewtronStar Hlog and QLN will determine it.

I have the QLN Graph but you must remember this is taken when the modem first sync's to the DSLAM and its not updated until I force re-sync.

Here is Hlog it looks ok to me, those 5 small blocks that peak down to 98dB are US & DS Band Partitions i think and I don't see those in the HG612_Modem_stats Hlog Graph.

[konrado5]

It seems it is 160m band radio interference. Are those tones always missing? Perhaps expanding QLN and Hlog graphs will be helpful.