So, margin started at 9 and deteriorated to 3.5 during that day. That often points to a modem/router problem as the margin normally tends to vary by +/- 0.5 dB during the day unless there is an external noise source.

In reply to a post by cantoris:

Started the day with a downstream noise margin of 13 and an upstream one of 6. Had one disconnect late morning and reconnected with a downstream margin of 9. That gradually went down over the day and when it got down to 3.5 just now I sensed an imminent disconnect. My Skype died briefly but no disconnect was seen on the graph.

Your sampling period on RouterStats is too long, if it fails to show a disconnection.

I always used 5 seconds - the minimum. Doesn't cause any problems. I recommend setting it to log to a file as well as graph, as that is quicker to scan visually with that interval. Then you can go to the right graph easily once you have found the time it occurred.

Edited by RobertoS (Mon 03-Dec-12 00:03:02)