I get disconnected fairly often, I have noticed my attenuation will be 58 then it will disconnect and it will be 57.5 and vice versa. My speeds have been fairly random, 4mbs, then 3mbps, then 2.5mbps. Then fairly recently it went up to 4.7mbps my highest ever, then 4.6 and its finally settled at 4mbps.
This has been going on for ages and I have phoned Sky multiple times, they never really fix it. At one point we were going to get a BT engineer come and check the line when it was really bad (was probably from flooding looking back on it) but they cancelled him a few days before saying they had tried to contact us by text message and because we never responded they thought the issue was resolved, yet we never got a text message to call them.
I'm sure this started before I got a the new wireless N router, but I did buy the router off eBay. It was brand new and ununsed though. One time I had to read the MAC address off the new router to the call service woman as they were still getting line stats from my old router, yet it wasn't plugged in! I'm sure my old router used to be about 2db lower attenuation, but when I plugged in this new one I remember it having a lower attenuation than the old one, so the attenuation must have crept up from about 55-56 to 57-58.
I wonder if it could be my upload speed that is too high and thats making it unstable? I remember it used to be 768kbps and has been 605kbps at one time.
Line noise does go down to 2.3db down to 1.8db fairly often, I know its not going to be long before it disconnects at those db.
When I ring up they always go on about resetting the router and trying the test socket everytime, its only so often I get put through to someone who can actually see my line stats and if theres any errors coming up on the line whilst they try different speeds.
If they weren't unlimted and cheap I would find somewhere else! lol
at one time I was connected at 4.2mbps for about 1 month without any dc. I have a faceplate splitting telephone and adsl and don't have the bell wire connected. Have tried different cables etc.
(Since writing this downstream db has gone to 3.6-4.1db)