SNR margin drop - possible electrical interference

Hi

I've got FTTC broadband with BT. Download sync speed is around 42 to 48Mb. SNR margin usually around 5db, but this fluctuates quickly (e.g. it could be 5 one second and then 5.8 just a second or two later).

An extension lead is wired into the original master socket (which itself is disconnected) and the lead runs around the edge of the living room into a new BT master socket on the wall, which the Billion router's connected to. (This setup was done by the previous homeowner!)

Since I moved in in 2018, I've had the occasional dropout but nothing too bad, with syncs often lasting for several weeks. At the end of November, after being synced for a month, the router resynced with a lower SNR margin (around 2 or 3db) and the sync speed was much higher than usual (52Mb). I assume this was DLM intervention.

This caused a lot of errored seconds and I assume the DLM intervened again as it resynced again at a higher SNR margin, lower speed and then the errors went. Since then there have been random resyncs once a week or so at random times of day. I have a Raspberry Pi and set it up to record the SNR margin each second.

I've found that every few days the SNR margin drops to below 2 for about 5-10 seconds but it doesn't cause a resync. Last night though it twice dropped down like this and went so low it caused two resyncs (I went into the router stats and it registered -4 db just before dropping). I listened to the phone line when the SNR margin dropped and there was no noise at all.

I've checked against when my heating kicks in and I don't think there's a link. I can't think of anything else that could cause it.

However, I've noticed the router can be sensitive to what I assume is electrical noise. For example I once switched a fan on upstairs and it caused a resync. I tried turning the fan off/on again and it caused another resync so it was definitely the fan. I rebooted the router, tried the fan again and it was then fine.

The router's near my Raspberry Pi and a couple of other power adapters for the TV etc., which I know isn't ideal, and neither is the odd master socket setup. However I've had it like this for years and it's not been a problem.

Is it possible that something like the fridge or freezer (in the next room) has started to cause interference on the mains? Or perhaps a nearby power adapter has started doing it?

I'm considering buying a Tacima mains conditioner to see if this will help, but I'd appreciate any advice as I'd like to ensure this problem doesn't worsen.

Thanks.

Are there heavy errored seconds (CRC’s) showing in the router stats ?

In reply to a post by davidw87:

I'm considering buying a Tacima mains conditioner to see if this will help,

It won't, save your money.

In reply to a post by davidw87:

I'm considering buying a Tacima mains conditioner to see if this will help, but I'd appreciate any advice as I'd like to ensure this problem doesn't worsen.

Just because mains events may be causing interference, it is not necessarily the case that the interference is getting into your router via the mains. Still less likely it is getting from the power supply into the signal from the cabinet - unless there is some hardware failure. Most likely it is airborne noise. In neither case will a mains conditioner assist. Of course, if you can borrow one to try, then why not - but it's not worth spending money

Fluctuations of 0.8dB in S to N are more or less to be expected. A drop of 4dB is significant and a drop of 10dB is serious stuff. Are you still on analog phones or still have the wiring in place? If you are that might suggest an avenue of investigation

In reply to a post by davidw87:

An extension lead is wired into the original master socket (which itself is disconnected) and the lead runs around the edge of the living room into a new BT master socket on the wall, which the Billion router's connected to. (This setup was done by the previous homeowner!)

i think this is now starting cause problems. Can you take some photos inside where the extension starts in the original master socket. Some of the other forum members then can have a look.

In reply to a post by Taras:

i think this is now starting cause problems. Can you take some photos inside where the extension starts in the original master socket. Some of the other forum members then can have a look.

Missed that. I agree, a phot or2 would be useful and definitely of the inside wiring. Who knows, it might be our old friend burglar alarm cable.

In reply to a post by DFScale:

In reply to a post by Taras:

i think this is now starting cause problems. Can you take some photos inside where the extension starts in the original master socket. Some of the other forum members then can have a look.

Missed that. I agree, a phot or2 would be useful and definitely of the inside wiring. Who knows, it might be our old friend burglar alarm cable.

from what the OP has suggested means, from my understanding is that he can't do a test behind the master socket which is worrysome when you have this type of fault. I don't understand what typing of extension cabling can induce issues which is why i suggested others to have a look at the wiring !

In reply to a post by Zarjaz:

Are there heavy errored seconds (CRC’s) showing in the router stats ?

It doesn't show CRCs but it shows errored seconds and severely errored seconds. In 20 hours of connection there's been one of each.

In reply to a post by DFScale:

In reply to a post by davidw87:

I'm considering buying a Tacima mains conditioner to see if this will help, but I'd appreciate any advice as I'd like to ensure this problem doesn't worsen.

Just because mains events may be causing interference, it is not necessarily the case that the interference is getting into your router via the mains. Still less likely it is getting from the power supply into the signal from the cabinet - unless there is some hardware failure. Most likely it is airborne noise. In neither case will a mains conditioner assist. Of course, if you can borrow one to try, then why not - but it's not worth spending money

Fluctuations of 0.8dB in S to N are more or less to be expected. A drop of 4dB is significant and a drop of 10dB is serious stuff. Are you still on analog phones or still have the wiring in place? If you are that might suggest an avenue of investigation

Is it likely then that the SNR margin dropping is due to interference on the internal wiring, rather than on the line coming into the house? I have an analogue phone plugged in but rarely use it. There's no noise on it though, even when I listened while the SNR had dropped.

In reply to a post by Taras:

In reply to a post by davidw87:

An extension lead is wired into the original master socket (which itself is disconnected) and the lead runs around the edge of the living room into a new BT master socket on the wall, which the Billion router's connected to. (This setup was done by the previous homeowner!)

i think this is now starting cause problems. Can you take some photos inside where the extension starts in the original master socket. Some of the other forum members then can have a look.

Is there any reason why it would suddenly start to cause problems?

Here are two photos:

https://i.ibb.co/ckTyWgM/IMG-20250114-151403944.jpg
https://i.ibb.co/xLfghKL/IMG-20250114-151536625.jpg

The top plate covers where the (underground) phone line comes into the house. Behind this is where the extension lead (off to the left) is connected and runs about 10 metres around the room to a socket on a wall which looks like a BT master socket.

Also connected is a short cable going to the bottom socket, but it terminates in the socket and isn't connected, so the socket is dead.

The connections behind the top plate seem to be made using some sort of transparent connector. None of it looks good to me!

Thanks all for your help.

It doesn't show CRCs but it shows errored seconds and severely errored seconds. In 20 hours of connection there's been one of each.

For me that rules out REIN being the cause.

I don't understand what typing of extension cabling can induce issues

The ‘alarm cable’ referred to is hideous stuff. All non twisted, multi strand.

In reply to a post by Zarjaz:

I don't understand what typing of extension cabling can induce issues

The ‘alarm cable’ referred to is hideous stuff. All non twisted, multi strand.

looking at the picture, there was several cut cables, un twisted too. I don't know what David's fttp path is, but if he has a longish wait, it may be worth somebody to put a nte 5c (or latest equivalent) and do the extension wiring properly ..... As theres no effective test socket, he has zero chance of resolving his snr drop. Errorr'd seconds also means re-transmission and effectively lower bandwidth.

In reply to a post by Zarjaz:

It doesn't show CRCs but it shows errored seconds and severely errored seconds. In 20 hours of connection there's been one of each.

For me that rules out REIN being the cause.

If it's not REIN, does that rule out internal wiring issues? Or could the internal wiring still be picking up interference from equipment like a freezer etc?

In reply to a post by Taras:

looking at the picture, there was several cut cables, un twisted too. I don't know what David's fttp path is, but if he has a longish wait, it may be worth somebody to put a nte 5c (or latest equivalent) and do the extension wiring properly ..... As theres no effective test socket, he has zero chance of resolving his snr drop. Errorr'd seconds also means re-transmission and effectively lower bandwidth.

Yes, there appear to be unused 'strands' in the cable which has been put in that have been cut and just left, so it's created a bit of a spaghetti effect behind that plate.

I checked about FTTP and it says it'll be available before December 2026 - not sure if that date will keep getting pushed back or if it'll genuinely be in by then. Either way I think I'll get a local telephone engineer to put a proper master socket on and disconnect the extension altogether. I looked at getting BT to do it but it seems they don't really deal with stuff inside the house.

I reckon you need a visit from Openreach.

I see no alarm wire.

But would love to pull that wiring about and see what goes where. You might have a bridge tap causing issues.

In reply to a post by davidw87:

In reply to a post by Taras:

looking at the picture, there was several cut cables, un twisted too. I don't know what David's fttp path is, but if he has a longish wait, it may be worth somebody to put a nte 5c (or latest equivalent) and do the extension wiring properly ..... As theres no effective test socket, he has zero chance of resolving his snr drop. Errorr'd seconds also means re-transmission and effectively lower bandwidth.

Yes, there appear to be unused 'strands' in the cable which has been put in that have been cut and just left, so it's created a bit of a spaghetti effect behind that plate.

I checked about FTTP and it says it'll be available before December 2026 - not sure if that date will keep getting pushed back or if it'll genuinely be in by then. Either way I think I'll get a local telephone engineer to put a proper master socket on and disconnect the extension altogether. I looked at getting BT to do it but it seems they don't really deal with stuff inside the house.

You can get your isp to order a service from or to do so but it will be expensive. If you do know of a local telephone engineer then do get them to sort it out. At the very least hopefully your snr issue will be resolved and if theres any further issues you can test things via the test socket. You may get faster speeds (after a dlm reset)

[edited to remove a stupid question which was answered in david's opening post]

Edited by Taras (Tue 14-Jan-25 22:09:52)

In reply to a post by davidw87:

Is it likely then that the SNR margin dropping is due to interference on the internal wiring, rather than on the line coming into the house? I have an analogue phone plugged in but rarely use it. There's no noise on it though, even when I listened while the SNR had dropped.

I am becoming suspicious of your phone wiring, particularly as you have an analog phone in use.

In reply to a post by davidw87:

Here are two photos:

https://i.ibb.co/ckTyWgM/IMG-20250114-151403944.jpg
https://i.ibb.co/xLfghKL/IMG-20250114-151536625.jpg

The top plate covers where the (underground) phone line comes into the house. Behind this is where the extension lead (off to the left) is connected and runs about 10 metres around the room to a socket on a wall which looks like a BT master socket.

Also connected is a short cable going to the bottom socket, but it terminates in the socket and isn't connected, so the socket is dead.

The connections behind the top plate seem to be made using some sort of transparent connector. None of it looks good to me!

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.

OK, the rules for sorting the wiring

• You need a straight run from the incomer to an NTE5c. No parallel connections, no intermediate sockets
• All your phone sockets for phones must be connected to the voice side of the NTE5c
• Your router must be connected to the data side of the NTE5c. You can have an extension to the router, in which case you must run the router on the extension, not on the NTE5c. No parallel paths or other sockets on this data extension

Once you have wiring compliant with these STRICT guidelines [they are not rules LOL], I would hope you see an improvement. But it is not worth mains conditioners, other counter measures or even any investigation until the wiring is compliant. By all means try a temporary lash up of just a single cable to a NTE5c [ie compliant with the guidelines above] and plug your router in to see what works with no analog phone wiring.

Hope that helps.

In reply to a post by Zarjaz:

I reckon you need a visit from Openreach.

Do you think the issue's more likely external or internal? Or too difficult to say?

In reply to a post by Taras:

What are your stats on your modem router?

Here's a screenshot of the stats, taken just now: https://i.postimg.cc/bJgDWFnt/Screenshot-from-2025-0...

That's after about 26 hours of connection so far. Checking the logs that the Raspberry Pi's been keeping shows no drop in SNR today or last night.

Will be interesting to see what happens in the coming days given the Pi's shown a drop in SNR roughly every 2-3 days over the last 10 days (and the two last night were bad enough to cause the resyncs).

Just in case the router was at fault, I reset it to factory settings yesterday evening (straight before the current connection was made) and restored my own config. It's been running for about 3 years (though has been rebooted a few times a year) so I don't know if a fault had developed that may now have been flushed out. I'm not sure if a router itself could cause a drop in SNR though.

In reply to a post by DFScale:

No parallel connections, no intermediate sockets

from the first image thats what comes to mind that the router and phones are running in parallel, all you would need an untwisted pair in that pathway and that may cause problems ..

The drop cable (or external cable from a BT66 external junction box?) connected directly to the back of a NTE5 master socket fitted with a filtered faceplate, CW138 cable (or CAT5e) connected to the A&B terminals on the filtered faceplate to a RJ11 socket (effectively a "data extension") might be a good solution. Router would be connected to the RJ11 socket and a phone connected to the front of the filtered NTE5 master if that is convenient.

Good luck.

Edited by 4M2 (Tue 14-Jan-25 22:37:34)

you have g.imp and interleave on at 4. The thing is you are asking if its internal or external in regards to the issue, with the current wiring you can't actually test if it is internal.

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

Yes the OP needs a NTE5 for testing, i.e. a test socket directly from the external feed.

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.

The orange ring wire can be removed,

Whilst bell wire removal is a fix for a possible cause of intermittent errors and lowered sync. I would suggest however that the ‘orange ring wire’ is a very vague term, because the bell wire, if attached is by no means always orange. In fact one leg of the main incoming feed will be orange, removal of this will cause a complete loss of service.

I think the suggestion of having a single NTE direct on the feed is the best idea, and get the filters replaced.

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.

Aha !
So you already an NTE and SSFP where the router is connected, then the voice is back ended to feed the phones elsewhere.
So all this talk of possible start wiring is most likely a smoke screen *unless* the install of the NTE has been botched.

Back then to my first reply … it’s not REIN. Replace the router and leads as a next step. If that doesn’t fix it, the OP must persevere with the service provider and get the line checked out.

In reply to a post by Zarjaz:

Replace the router and leads as a next step.

To be on the safe side I think replacing the NTE and SSFP might be a good idea also...certainly doesn't look like an Openreach guy would have done that wiring job!

To be on the safe side I think replacing the NTE and SSFP might be a good idea also...certainly doesn't look like an Openreach guy would have done that wiring job!

No harm in replacing those for sure. It would be another box ticked.

On your second point …. I would differ I’m afraid to say.
As the years pass, many of those who were slavishly taught to run wiring ‘just so’, and took a little pride in their work are becoming thinner on the ground.

In reply to a post by Zarjaz:

To be on the safe side I think replacing the NTE and SSFP might be a good idea also...certainly doesn't look like an Openreach guy would have done that wiring job!

No harm in replacing those for sure. It would be another box ticked.

On your second point …. I would differ I’m afraid to say.
As the years pass, many of those who were slavishly taught to run wiring ‘just so’, and took a little pride in their work are becoming thinner on the ground.

Theres no harm in the wiring replacement as its a mess and whilst David does seem to have a filter nte box in the system, any test he would currently do wouldn't test for the wire-mess!. He's not going to have a worse service.

I do agree on the second point, as time has gone by we now have standards to work to; which have become stricter over time.

In reply to a post by Taras:

... whilst David does seem to have a filter nte box in the system ...

... but from what we know it almost certainly is not doing anything useful, because there is other wiring and a phone on the incoming line ...

In reply to a post by DFScale:

In reply to a post by Taras:

... whilst David does seem to have a filter nte box in the system ...

... but from what we know it almost certainly is not doing anything useful, because there is other wiring and a phone on the incoming line ...

yeah its in a pointless place in the "phone cabling network"

I still reckon the voice is ‘back ended’ from the NTE …

Just to add another layer of intrigue, I think my router may be playing up which could be the cause of, or contributing to, this occasional issue. For quite a while now when I access the router's admin page (i.e. 192.168.1.1 for me) it sometimes takes 15-20 seconds to load.

I still have the Raspberry Pi, via telnet, logging SNR every few seconds. Today when I went to the admin page it took a while to load and I noticed the SNR dropped from 5.5-6.5ish to about 4.3. Once the page loaded, the SNR rose again to 6ish. I tried it a few times and the slow-loading admin page definitely hit the SNR.

I wondered if it was to do with load on the router, so I tested downloaing a large file and the SNR did the same during the download - in fact it even stopped telnet reporting the SNR for a while.

I don't know why accessing the admin page is sometimes slow, but I don't see why it'd actually affect SNR. Same for downloading a large file. Is this something to do with the way the router's reporting the SNR, or is it possible the router's playing up and it's not able to process the DSL signal properly?!

The router is a Billion 8800NL which is 4.5 years old.

Edited by davidw87 (Sun 19-Jan-25 13:05:10)

In reply to a post by davidw87:

Just to add another layer of intrigue, ...

In your position, I would be getting the wiring sorted and not looking too closely until that is done. Obviously the router is not happy, but you won't make sense of anything until the wiring is resolved.

Ceteris paribus 😇

In reply to a post by davidw87:

I still have the Raspberry Pi, via telnet, logging SNR every few seconds.

You may find the router doesn’t like one IP accessing via Telnet and another via HTTP and allocates its resources to the first. Your SNR increasing could just be a UI bug.

Hitting the telnet interface every few seconds may be too much, try reducing this to 30 seconds or every 60 seconds.

In reply to a post by DFScale:

In reply to a post by davidw87:

Just to add another layer of intrigue, ...

In your position, I would be getting the wiring sorted and not looking too closely until that is done. Obviously the router is not happy, but you won't make sense of anything until the wiring is resolved.

Yes, I'm definitely going to get that wiring replaced. It's weird about the router playing up in the ways I described though - perhaps it's nearing the end of its life after 4.5 years.

Just an update on this:

I've not been able to have the internal wiring sorted yet, but I bought a second hand Billion router from eBay (the 8800NL v1, which is apparently better than the v2).

I tried it and it synced at 46Mbps and the SNR margin was rock solid at 5db. Clearly the original router had become faulty hence its lower sync speed and the fluctuating SNR. I still plan to sort the internal wiring but it's not so urgent now.

I'm still monitoring the SNR for now. It's been rock solid for days but this morning it jumped, literally within a few seconds, from 5.9dB-ish to 8.8dB-ish. No resync occurred. The attainable rate is showing at 54Mbps - faster than anything I've ever had on this line.

The digital voice switchover's happening in my area this month. Is it possible a 'neighbouring' line had their voice switched off which has reduced noise etc. and means my line could now get a higher speed? I'll see what happens with the SNR but it's been solid at 8.8/8.9dB for a few hours now. Strange this jump happened without a resync.

Edited by davidw87 (Mon 03-Feb-25 11:08:33)

Noise margin can change without a resync and if you reboot while you're noise margin is higher than 5 or 6 you should get closer to your max speed.

Interestingly, at about 2:30pm the SNR suddenly dropped back to 6dB, having been 8.7-8.8 solidly for over four hours.

This isn't the usual SNR issue caused by noise or a faulty router, so I still suspect some sort of exchange work given the switchover that's happening in the next couple of weeks here.

Not a big deal but just intriguing!