I've been connected to a FTTC service (Plusnet) for over 3 years now, speeds generally great at around 23-28Mbit (has been improving over the years!) - this is great as I live around 1.5km from my cabinet. Estimated speeds on a clean line at between 13-21Mbit.
I am currently and have always been plugged in to the master socket (test socket with micro filter at the moment) with a faceplate filter
I recently logged an issue where my router displayed connection speed became 'stuck' at 19999kbps and thought this was unusual as it had never been so low (this figure did actually improve to 22400kbps on the morning just before the engineer visit).
A fault was found and a (non-broadband) Openreach engineer 'fixed' the issue with the line (apparently no dial tone - we never use the land line so were not aware). Unfortunately this fix has made our connection speed even lower (ranges between 13-18Mbit - it has never been this low before!) and more unreliable where the connection appears to drop more often especially in the evenings.
I have told Plusnet but they give the 'It's within expected range' response which is unhelpful considering the connection has been great for the past 3 years!
Interestingly, since this fix, I now notice dslchecker has changed the 'Bridge Tap' part from N to Y which could explain the issues.
Before requesting a further investigation from Openreach and possible incurring a call out charge I have done some investigation to ensure there's no dodgy wiring. We only have one extension which will be removed as this is never used. I have also taken a look at the back of the master socket (Openreach side) to ensure everything is correct, which it is. So ultimately, there's been no changes to our wiring since we've had FTTC.
I have however noticed that this appears to be a very old master socket type, probably 80's. I also noticed that when I touch the area illustrated in this image the Noise Margin will improve by 1-2db (ie, go from 6.2db to 8.1db) - is this normal or does it show the socket is faulty?:
At the moment I'm a bit perplexed on what to do next. I am beginning to wish I never reported an issue!! Ha!
I currently use a Netgear D6400 router, as I understand it this doesn't give out much in the way of useful stats.
Any thoughts or advice?