Drastic SNR fluctuations, random connection drop outs

Disclaimer: I'm not very technical or knowledgeable about networking but am at my wits end, so hope you all may be able to help!

I've been experiencing issues with my ADSL connection for about 3 weeks now, when it had previously been fine and stable. My ISP is NowTV. The connection will drop multiple times per day - there is no rhyme, reason, pattern or logic to why it happens. It usually drops out between 5-10 times per day, but always reconnects a minute or two later.

It could drop out 3 times in 15 minutes or once in 6 hours - no logic to it. In fact from Monday afternoon to Tuesday afternoon this week it was pretty stable and didn't drop out at all. Then today it's been basically unusable. I'm working from home and am now getting a lot of grief from work when I drop off of video calls with colleagues and clients. NowTV have been able to see that I've been experiencing regular drop outs but have really only sent out engineers who can't find any issues.

- I've tried 3 different routers; all exhibit the same issues.

- I've tried taking the master socket faceplate off and plugging into the test socket with a filter; no difference.

- I've had 2 engineers round, both of whom have found no faults on the line, have traced the cable all along the outside of the building, back to the pole and back to the exchange. They can find no fault and no noise on the line.

- I've tried isolating every electrical circuit in my apartment at the fuse box, other than the circuit for the sockets because obviously the router needs power. Still the issue persists.

I began monitoring my connection with RouterStats-Lite about a week ago and have noticed wild fluctuations in noise margin, amid periods where it is stable - if high. These fluctuations often cause my connection to drop out, but not always. Take a look at some snapshots from today for an idea of what my SNR is doing:

https://ibb.co/W6J4mTs
https://ibb.co/9w3wq0T
https://ibb.co/V99Dqrr
https://ibb.co/DtM82sC
https://ibb.co/5MLNC4m
https://ibb.co/KrZ0qyM

I rent a small apartment on the 3rd floor of a moderately old building. Other than my mobile I don't own a phone, so nothing else is plugged into the socket. The only devices that use my connection are 2 laptops, mobile phone and an iPad.

Any ideas folks? Am I looking at REIN interference here? I'm really struggling to imagine where it could be coming from if so. Nothing has changed in my home, many other apartments around me in this building are also empty at the moment. I'm absolutely at my wit's end here, and I don't think my employer is particularly happy either.

Thanks for any insight!

Could you post some line stats please ? Attenuation, sync rate, SNR, error rates.

These figures will be somewhere amongst the web interface from your router.

Have you tried replacing the router ?

Here is a snapshot of my router stats from this morning (8.20am);

https://ibb.co/GV8gfFy

The system up time shows just less than 24 hours - it was reset when an engineer was here yesterday morning. I have a WAN up time of just over 6 hours, so obviously the connection dropped and re-synced sometime around 2am this morning. I'm not sure if that is normal.

And yes, I've tried 3 different routers - all exhibit the same issues

Edited by deleted (Thu 15-Oct-20 08:23:42)

Do you live inside the exchange? Pretty decent stats for ADSL.

You appear to be suffering from an intermittent noise source that's affecting the SNRM, causing sync to drop.
That's even with a 15dB margin.

I'm not too sure how the Sky ADSL works but i expect it's probably automated.
You could call and ask if the noise margin can be increased. It might lower sync a little bit "might" help the line hold sync.
That just masks the issue though.

Whatevers causing this can be very difficult to spot. It could be a physical line fault or noise from something electrical.
Generators, pumps, etc, can cause this. It isn't even necessarily something at your property but can be anything near your lines run to the exchange.

Thanks j0hn83. Yes, I am pretty close to the exchange; my upload speed has always been pretty [censored] but for a single dude who doesn't need a particularly fast connection, the download speed has always been fine, when the connection is up and stable.

I have an AM radio arriving in the mail today so will see if I can track down any sources of interference.

I will probably jinx it now, but since it dropped and resynced overnight at ~2am, it has not dropped again and has been relatively stable all morning at 12dB.

EDIT: Yep, jinxed it Connection dropped at 11.50 and reconnected a few mins later. No obvious cause, was just sat at my desk working.

Edited by deleted (Thu 15-Oct-20 11:56:28)

Your upstream speed as far as I remember is good for ADSL2+ - it is low compared to VDSL and other tech but good for ADSL.

As others have said there does appear to be a MASSIVE noise source affecting your line. The engineers would need to be specialists for searching for noise sources and even then would have to be there at the right time - and obviously you will have to hope it happens whilst you are listening to the radio as with an intermittent issue you could be waiting quite some time. Does it happen every day of the week - if it stops at weekends then it would potentially point to a manufacturer or similar kicking out noise. If it is every day then it could be a dodgy TV (as was reported in the news a few weeks back where a whole village were affected).

Have you spoken to neighbours? Do they see the same issues? If they don't then it maybe localises the issue to your house and potentially something very close to the router/line route.

It does look like an intermittent noise source. Finding it may prove very tricky. Remember not everything that creates noise on a MW radio is an actual source of DSL interference.

Is there any FTTC available in your area?

Well, following a pretty stable morning, from noon to 3pm-ish today was anything but stable...

https://ibb.co/mC20z7Y
https://ibb.co/rs9YHhD
https://ibb.co/3BcXM9C

Again, I cannot identify anything that happened during this period. Anyway, my AM radio showed up so I'll have a little hunt around the apartment this evening and see if I can find anything.

FTTC is available in my area - I had been toying with the idea of upgrading. However, uncertain job stability going into 2021 and a general lingering sense of this city not being the place for me long term, has meant I've been trying not to tie myself into any new long term contracts right now. We'll see how it plays out though.

Thanks everyone.

I do believe NOW broadband do have FTTC with one month contract if you choose this option