I've just come to this thread, (and thanks to Alastair and Bill for the links to my site), and as others have said, you should be getting a much better connection than you are. The difference between the two is huge, so noise margin and interleaving I don't think are what we should be worrying about at this stage. Have a look at the Speed v Attenuation graph pointed to on my
Useful links page.
Your attenuation should not be varying between 33.5 and 42dB either. It can change by 1dB perhaps between connections using a particular router, or possibly as much as 3dB by changing router, but 8.5dB is OTT.
Bill suggested you look at the Ring/Bell wire page in my Troubleshooting section. On that page is a picture of the most common sort of master socket, opened up. On the wall at the back is what is called the test socket.
You need to connect a working filter into that, and then connect a router to it using just a short ADSL cable that comes with routers. Post the stats when connected like that, and those should show whether the problem is at your end or outside your control. It is very important that you don't use a plug-in phone extension cable at any point between the test socket and the router for this test, even if it means some messing around.
When you are connected like that, as confirmation that you are on TT please can you run
this speed test and post the link to the result. I think that will show the true ISP rather than WebTapestry, though I may be wrong.
Talking to support until we have that info isn't much use.
If/When you do move, you can get Sky LLU on either a line reverted to BT, or as has been suggested perhaps moved to Sky. The on-going costs won't be much different, but let's go into that in more detail after we have found out whether the connection problem is at your end.
Hope that helps.
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