F.T.T.C instability.

[lofgents]

Firstly I apologise for posting in English.

I have an issue with vdsl2 FTTC my SNRM has recently begun to display rapid fluctuations when my neighbour disconnects his modem. He is about 100 metres from my house and goes away for some days at a time disconnecting his modem while he is away, when the modem is unplugged my SNRM is varying and when it is connected the SNRM is smooth and stable. FEC and CRC are large when the instability occurs.

Thank you for reading and if anyone has any ideas what is causing the problem I would appreciate it.

[puffy]

kinda strange. the opposite would be more likely, as your neighbour leaving should mean less crosstalk for you

but well its only fluctuating from 7 to 8 so no big deal. graph just makes it seem dramatic, but its small fluctuation really.
fec dont matter, they re corrected errors, its just a statistic.
crc are also ok if they re in the range of some hundreds per hr.

tldr unless you have trouble with the connection, nothing big really.

[lofgents]

Thank you very much for your reply

Here is the info of 24 hours CRC with neighbours modem disconnected.
CRC: down 1462 up 18815

down looks OK but up is that excessive.

and connected
CRC: down 35 up 3

Unfortunately the neighbour spends a fair amount of time away from home especially during the winter, from the middle of June he will be here until September so I can afford to wait and see what happens then.

Thank you again for your help

[puffy]

yeah thats strange. usually other connections affect negatively not positively.
18k arent few but aren't too many if you have no problems. and your snr is bit on the low side, default is 9.
if connection degrades or loses stability, then contact your isp,
or an electrician might be needed to check your cabling.

imo just monitor it if you have no problems, surely something goes wrong, but it might not have any impact.

[lofgents]

We have a lot of power outages and my modem will sync down to a low level of snr it is manufactured by Billion,so I do not suffer from disconnections. The vdsl2 system here became live last year, the cabinet had been installed some 12 months previously. My cable from the house to the Cosmote connection is a couple of months old and is cat 6 outdoor cable. Recently checked by Cosmote techs as they tried to explain the behaviour of the system as described below.

The strange thing that no one can explain (even Cosmote techs etc.) is the behaviour of the snr, during the daytime the snr drops and in the evening the snr rises which is completely opposite to everything I have read on how it should perform.
It is mainly my curiosity about why this noise should have appeared recently without any noticeable change in my or my neighbours circumstances.
My connection speed is good and stable so I will leave it as is and monitor it.
Thank you for your advice and replying to my problem.
All the best to you.

[puffy]

frankly if snr stays between 7-8, that's no big deal at all. its just 1 pt fluctuation and that happens with most connections. mine too.
18k crc errors a day are tad on the high side, but we don't really have hard numbers on how many crc are bad. id say they re on threshold levels.
what happens though is strange yeah, but lots of strange things happen you re lucky if you arent affected in any way.

[lofgents]

Thanks its my ocd engineering background monitoring changes in data and trying to find a cause and solution. I will leave it alone as I have a good speed and there are no drops in connection other than when we have power outages.

Thank you for your advice and for your excellent English.