Noise margin

[Carl]

Hi - the network analysis speed test shows my Sky Fibre experiencing a 10 Mb/sec drop in download speed which persists for a month or so, followed by a further drop of 10 which also persists. On the Sky community, they suggested checking the "noise margin" per below.  Is there a way to check that?

 

(t"here is a chance that when you were first connected there were few users attached to your cabinet. As more and more are connected there is more interference, thus reducing your speed.  A good way to judge is to look at your noise margin, if it is around 6db you are getting as much as the line can handle, if it is up in double figures then you may have to have your line reset by BTO.")