These sort of problems I had when I was on ADSL Exchange Only Line but never again after FTTC became available in October 2019.

There was absolutely no solution for me when I was on ADSL. Perhaps what solved me partially was informing my ISP to raise the SNR cap to 9dB and that solved my problem. I had exactly the same experiences as you with the dB dropping to 0. Sometimes the connection was being maintained but the pages will simply not load before the SNR will recover back. This observation for me was mostly happening only in the early mornings around 10-11:30am. But I never knew why it was causing the SNR to drop.

Have you checked to see if the router is fine? Does the router at least maintain stable system uptime? This will rule out router fault.

I see you do not have an NTE5C Master Faceplate. It's worth considering this https://www.amazon.co.uk/Master-Telephone-socket-Fac... as it might help with the stability eliminating the need for a separate micro filter.

Have you checked to see if there is an orange ring wire? Some people say that disconnecting this resolves many of these issues. Have you tested to see if anyone rings your phone landline whether that causes a drop in your connection? You can check 1471 to see for any missed calls and see if that coincided with your drops.

Also, you being with BT have you looked into getting BT to upgrade your analogue phone into Digital Voice? You're not supposed to have dial tone if you are connecting your phone to the master socket unless you are still on Analogue phone service. With BT you should have Digital Voice. Phone being connected to master socket will not return any dial tone so you will not hear any line noise.

I am with BT FTTC and I have a super stable service.
Firmware updated:Wed Jan 8 17:37:59 2025
Board version:R01
GUI version:1.80 11_07_2023
DSL uptime:5 days,22 Hours41 Mins47 Secs
Data rate:19.357 Mbps / 78.87 Mbps
Maximum data rate:19.357 Mbps / 80.753 Mbps
Full Fibre (FTTP) Mode:Off
Noise margin:6.1 / 3.2
Line attenuation:10.7 / 16.8

There was a firmware update on the 8th of January for, which my connection uptime was of-course naturally reset. But prior this I have had a stable 173 days connection up time. Mine at least I know is related to the firmware.

My noise margin is at around 3.2dB and I maintain a stable sync around 78-80Mbps at all times. But that may be because my cabinet is closer and we don't suffer cross talk anymore seeing how many people have upgraded to Community Fibre here.

Have you got any Altnet available in your area or a plan for one?

Of-course in my case when I was with TalkTalk FTTC and Analogue sometimes when the phone rang or there was a miss call or if I plug/unplug the telephone then the broadband would lose connection. But with BT I no longer suffer from this problem as Digital Voice does not affect the noise. Phone calls do not trigger drop-outs. I've mentioned this before 2 years ago and some people here have said I simply masked my problem. Frankly, I don't care if it is masked or not, I care that it solves the problem and for me that has resolved it for good.

You could try this as an option. Do you know historically whether you've always had this problem? Is this a recent problem?

The OP has a direct in ground armoured feed. The end of the two pair feed is somewhere in that picture they posted.

In reply to a post by Zarjaz:

The OP has a direct in ground armoured feed. The end of the two pair feed is somewhere in that picture they posted.

Thanks for pointing that out, I missed seeing "The top plate covers where the (underground) phone line comes into the house." in one of his posts.

FTTP could be a long time a'coming then...

FTTP could be a long time a'coming then...

Nah … just build a new external duct .

In reply to a post by DFScale:

OK, that looks a mess. You need a faceplate filter somewhere in the installation. An NTE5c as suggested by Taras. Can you tell us where your router is plugged in? And what filters are you using?

Looking at the arrangement, it seems a fair bet that the incomer is fed to the lower socket, either in parallel with the circuit going to the left, or the circuit goes into the lower socket and doubles back in the same cable. Either way, this is asking for problems. There also appears to be a cable coming out from the bottom of the lower socket.

In reply to a post by Taras:

do you have any micro-filters on any part of the wiring (as per dfscale's question)?

There's an earlier version of the NTE5c on the other side of the room, connected by a long cable (seen going off to the left in the photos) which is connected to the cable coming in from outside. I believe this has a built-in filter as it has two sockets - one for phone and one for broadband. The router is plugged in here.

The incoming cable from outside definitely comes in via the arrangement with all the wires on show. The bottom socket is totally disconnected, as the wires going into it from the top and from the bottom (which I think goes to another socket in the kitchen which has always been dead) aren't connected inside.

In reply to a post by BLaZiNgSPEED:

Have you checked to see if the router is fine? Does the router at least maintain stable system uptime? This will rule out router fault.
...
Have you checked to see if there is an orange ring wire?
...
Have you tested to see if anyone rings your phone landline whether that causes a drop in your connection?
...
Also, you being with BT have you looked into getting BT to upgrade your analogue phone into Digital Voice?
...
Have you got any Altnet available in your area or a plan for one?
...
Do you know historically whether you've always had this problem? Is this a recent problem?

Router seems to be fine on the face of it, but I've known routers to lose sync (but not totally reboot) in the event of a powercut, so I still wouldn't fully rule out a router issue.

Not sure about the orange ring wire given the mess of cables (as per the photo).

Ringing the landline doesn't cause a connection drop.

I've not looked into getting Digital Voice or Altnet - perhaps these are things I should consider.

I think the problem with very occasional resyncs at random times has always been there but seems slightly worse lately - perhaps once a week now, whereas it was much rarer a year or more ago. I don't know if the SNR regularly dropped as I've only just started monitoring it properly.

Thanks all for the help. I think I'll contact a local phone engineer (who has 57 five-star reviews on Google and is an ex BT engineer) to install a master socket where the cable comes into the property, then plug the router directly into that.

In reply to a post by davidw87:

I think the problem with very occasional resyncs at random times has always been there but seems slightly worse lately - perhaps once a week now, whereas it was much rarer a year or more ago. I don't know if the SNR regularly dropped as I've only just started monitoring it properly.

Thanks all for the help. I think I'll contact a local phone engineer (who has 57 five-star reviews on Google and is an ex BT engineer) to install a master socket where the cable comes into the property, then plug the router directly into that.

I think with the extra information, you may have a duff microfilter in extension socket or a failing one. The local engineer is the best route, sadly but still should be cheaper than via your isp and should mean if you need to test without extensions you can!

Good luck. Please do come back tell us the results.

In reply to a post by davidw87:

There's an earlier version of the NTE5c on the other side of the room, connected by a long cable (seen going off to the left in the photos) which is connected to the cable coming in from outside. I believe this has a built-in filter as it has two sockets - one for phone and one for broadband. The router is plugged in here.

The incoming cable from outside definitely comes in via the arrangement with all the wires on show. The bottom socket is totally disconnected, as the wires going into it from the top and from the bottom (which I think goes to another socket in the kitchen which has always been dead) aren't connected inside.

So putting together the info across several posts, it looks like you have a phone connected via some wiring to the incomer before the NTE5c

In reply to a post by davidw87:

I think I'll contact a local phone engineer (who has 57 five-star reviews on Google and is an ex BT engineer) to install a master socket where the cable comes into the property, then plug the router directly into that.

Yes. And the voice and data circuits separate after that. Then let's see how you get on, but you will have addressed a major weakness in your setup.

In reply to a post by davidw87:

...install a master socket where the cable comes into the property, then plug the router directly into that.

That's definitely the best thing to do at this stage if its convenient to plug your router into a NTE5 fitted with a filtered faceplate (older NTE5's with Mk3 plates are preferable) with a short RJ11 lead.

Looks like you've got plenty of slack black incoming cable to work with so the job would be very straight forward. I wouldn't run a filtered, hardwired CW138 phone extension cable from the NTE5 unless it was absolutely necessary though.

An easy way is to check your Hub.
In my case it is like this.
Network uptime:

7 Days, 03 Hours 00 Minutes

System uptime:

7 Days, 03 Hours 01 Minutes

If you see that the System uptime is maintained but only the Network uptime resets then that should give you clues that the problem is with your line. But if the System uptime also resets identically along with the Network uptime then this is a strong indicator that the router is faulty! Of-course you should make sure this isn't a power cut. If it is happening without a power cut then the problem is the router.

If you are seeing the router can't maintain sync then it could be either fault with the router or the router is overheating. Check to see if the router has got a lot of dust and try clearing it! Make sure you also don't place your router next to your central heating or pipes as the router can overheat.

Check with your neighbours and ask them if they are also experiencing network issues. That way you can rule out the fault within your property or the line outside. If their connection is stable then the problem is somewhere in your place.

Of-course they need to check their router stats because sometimes some people might think their connection is stable but they never check their router stats to see if this is the case or they never experienced the drop-out while they were using the internet.

The orange ring wire can be removed, see here https://kitz.co.uk/adsl/lowSNR.htm
https://kitz.co.uk/adsl/socket.htm#ringwire

Digital Voice is something you should consider as a test if you don't have an Altnet. To check what Altnets are available (if any) check this website. https://checker.ofcom.org.uk/en-gb/broadband-coverage# Enter your postcode and it will tell you what networks are available in your area. Obviously, this isn't always 100% accurate as sometimes the ofcom checker misses out networks that are available and might show networks that aren't available. However, this is handy as then you can crosscheck with the ISPs official website and see if they are available or planned.

There are many Altnets like Hyperoptic, Virgin Media, Gigaclear, Zzoomm, Community Fibre (if you are in London or if you formerly had Box Broadband), CityFibre, Netomnia, Freedom Fibre, OFNL, etc. Go through all of them even if they aren't available yet keep an eye to see if there are plans and try to register your interest. Get your neighbours to do the same.
Keep an eye on this map as well https://bidb.uk/ This gives roadworks of all broadband ISPs that are installing Fibre within your area. If you see some Altnets installing around your area then you could try to register your interest with them as realistically they are more likely to connect yours too.

If you have an Altnet then switching to Altnet FTTP may be a more rational idea as then you won't have to bother troubleshooting your existing copper line. But of-course, if those aren't yet available and the plans aren't there yet then contacting an engineer or your ISP to call an Openreach engineer may be needed.