Hi Guys hope you may be able to throw some light on this one, have been looking at Bt dslchecker over time and noticed the speed it shows my line is capable off is slowly reducing. Is this a BT trick to plug more user on the same port or a genuine degradation of my line over the past 3 months which I find hard to believe.
I have shown three sets of images below with the oldest first. As you can see my line speed has been reduced from 60Mbps to 55 Mbps its not a problem at the moment as I am still getting the full 40 -10 line speed that PN sold me, but at this rate Bt will have my line down as only being able to deliver a speed of 20Mbps at the end of the year.
... I am still getting the full 40 -10 line speed that PN sold me,
Unfortunately Plusnet haven't sold you a full 40/10 service, they are supplying an up to 40/10 service.
Having said that, I once had a boss whose favourite quote was 'The truth is time varying'. I guess that what you are seeing is BT adjusting their estimated speeds based on real world testing. The slow down could be caused by increased cross talk as more users get connected to your local fibre cabinet. It's interesting to note that the first two sets of results were both from tests conducted on 18/5/17. The third test date is 26/2/18, so the actual two sets of tests were conducted 9 months apart, so you are not seeing monthly drops.
My advice is to just forget about it, there's nothing that will be done about it and you will probably find that it now stabilises.
I think the "Last Test Date" shown only applies to the "Premise Environment" section, not the estimated speeds.
The speed estimates are currently based on the line speeds of "characteristically similar" lines. Apparently in the future (2019), your speed estimate will be based on the actual performance of your own line.