Help with SNM problem

[Claire S]

Hi
I have been having a problem with losing my MAX conection for about two months now. Im using a utility called routerstats to monitor the SNM on my line and have found that the disconnections are being caused by sudden large noise spikes. I have had MAX for about a year on this line and the IP profile has always been rock solid at 4meg (I usually synch at around the 4700kps mark) up until this problem started.
The line stats are: 48/27db attenuation, line length 3300meters,target SNR12db. The problem is that my connection usually drops during one of these spikes and when it does reconnect, its at a much reduced synch rate. When I monitor the SNM then force a reysynch when the spike goes, I synch at my normal rate. Usually by the time this is done, my IP profile is dropped and obviously the exchange takes time to put it back. MyISP has a had openreach do a lift and shift etc which has not cured the problem.
What could be causing these spikes recently? Faulty line connection, water, interference off something?
Any advice/opinions greatly appreciated.

[Claire S]

Screen shot for reference

[peterb]

My guess would be interference of some sort - does it occur at aboutthe same times each day? If so iit could be a central heating clock or heating thermostat switching an inductive load like a central heating pump. If you are out in the country, farm machinery could cause noise spikes on the mains line which your telephone line is picking up. If it is interference being generated by one of youyr appliances, it could be easy to fix - the problem is identifying the source. If it something outside your control, tracking it down can be very difficult - fixing it could be even harder. The problem is made worse by a relatively low SNR - although that isn't much consolation to you.

[Jay]

I had this, it was a dodgy filter and a fax machine. Took ages to work it out though!

[Claire S]

Its only started fairly recently, no real pattern to it. I even isolated all my electrics and made sure everything was turned off except the downstairs sockets that the router is conected to. Its definitely not my heating etc and I havent introduced anything electrical into the house recently. Its usually in the evening but does happen early hours, daytimes etc. It definitely seems to be external from our house which is why I was thinking it could be a BT wiring problem or something interfering with the main phone line. How the hell are you supposed to find it?!

[aidanjt]

Anything beyond the PSTN box in your house is the responsibility of BT to correct as soon as reasonably possible.

[Claire S]

2 months so far

[peterb]

You could try changing the filter - bit of a long shot though - still, for £6 it is w2orth a try.