Ordering FTTC - Low estimated speed and possible line fault

A friend currently has BT ADSL and gets about 17MB down and less than 1 up. The conection is quite flaky and seems to be worse recently after the recent lightning.

I suggested ordering FTTC however BT say they'll get 9 mbps down and 1 mbps up and the wholesale checker suggest 17/1. Either way the upload is poor.

The house is an old house and the phone wiring hasn't been changed in a long time and there is no normal BT master socket.

It looks like the overhead cable comes from the pole to the eaves of the house where it goes to a small box before being split into two wires each going to an internal phone socket. Only the one socket is used nowadays.

Their pole serves 5 other properties and all but one of those can get 80/20 via FTTC.

All of the properties look to be served from the same cabinet although I'm not actually sure where it is. Not that it matters for FTTC but the actual exchange is less than 200m away.

In my view I think the wiring is to blame for the poor speeds reported by fibre but as there is no master socket or easy way to disconnect the extensions it's not easy to check ourselves?

What's the best way to get it resolved, I don't want them to sign to a fibre contract to be told that 9/1 is the best they can get?

FTTP is being rolled out in the area and is near to them but they can't get it yet.

If needed I can provide postcodes and further property details via PM.

Needs someone to have a look at the address details, alas been in desk chair since 8am so taking a break for the night.

if the checker is wrong and the physical distance is short and the house wiring does not impede service speeds, then if a provider orders a 40/10 product with sales estimate of 9/1 when the person connects the only limit is the 40/10, so if line is short and can go fast it will go as fast as it can. Sales estimates do not impose a cap.

Thanks for the reply.

If they order FTTC and it only gives the 9/1 speeds expected then where do they go from there?

Where does the responsibility for the wiring change?

My understanding is that the master socket and before is BT's responsibility and anything after that is the customer's however in this case there isn't a master socket and the cabling splits where the cable is attached at the eaves.

In reply to a post by StuB:

Thanks for the reply.

If they order FTTC and it only gives the 9/1 speeds expected then where do they go from there?

Where does the responsibility for the wiring change?

My understanding is that the master socket and before is BT's responsibility and anything after that is the customer's however in this case there isn't a master socket and the cabling splits where the cable is attached at the eaves.

The split of the cabling at the eaves is the problem. If you look just below the table in the BT Wholesale estimator I expect you will see "Bridge tap detected", which is the technical term for that.

It badly affects ADSLx, costing as much as 2.5Mbps connection speed, and is even more damaging on FTTC. The BTW estimates themselves for a given line/property adjust over time to the actuals.

If there is any safe way you can identify (with certainty) and disconnect the unused wire from the eaves inside the box on the eaves and just tape over the disconnected wires so they don't cause a short circuit with anything, then even the existing connection will improve.

Technically you are not allowed to do this, but plenty of people do similar. Almost all though with bridge taps existing inside the premises, which is much safer for the person doing it.

If you/they managed to get the chosen provider to order an engineer install of the FTTC because of this problem, it will cost a little more to install but sorting out bridge taps and other potential problems is what that service is for.

These days I'm not sure if the cheaper providers offer engineer installs, but that isn't something I can help with.

After further thought, forget the DIY (or suitable person) idea. A modern NTE is needed anyway for FTTC, rather than any workaround to use the existing socket.

An engineer install is by far the wisest course of action. Failing that, a two-stage approach, the first stage being paying Openreach (arranged through the existing provider) to sort out that wiring. Probable cost quite a bit above £100.

An engineer install of FTTC including the wiring and socket fixes would almost certainly be cheaper, plus some sort of warranty.

Edited by RobertoS (Tue 25-Aug-20 02:08:25)

In reply to a post by StuB:

I suggested ordering FTTC however BT say they'll get 9 mbps down and 1 mbps up and the wholesale checker suggest 17/1. Either way the upload is poor.

Can you show a screenshot of the wholesale checker output - with phone number blanked out, but showing the exchange and cabinet?

It is suspicious that the FTTC estimate of 17/1 is exactly what the user is currently getting on ADSL.

I wonder if this is actually an ADSL estimate, and FTTC is unavailable for some reason.

For an FTTC line where the neighbours are getting 80/20 I would not expect a bridge tap to bring the speed down so much.

Thanks for the reply Bob.

I'd never heard of the term 'bridge tap' so thanks for that. If the wiring was inside I'd consider doing it myself however up at the eaves and at someone else's house then an engineer can sort it.

Any specific ISP's for an FTTC install that would be better to sort out an engineer install?

Is there any way to get an engineer FTTC install and guarantee a better speed than quoted or will they all fall back on the speeds quoted by the checker?

You can try joining an ISP like Vodafone FTTC that would install a new telephone line for free which will eliminate all the internal wiring issues.

But, if the estimate speeds are low and goes up to 17Mbps then there is no way a new line will solve the problem.

Check this site here https://www.broadbandchecker.btwholesale.com/#/ADSL
Enter phone number or postcode and check for your estimated speeds. It is unlikely that 17Mbps is the highest attainable speed under FTTC even with a 1km long cabinet for example.

At the very least 24-30Mbps should be receivable under FTTC. If those estimates are low then your line should not make much of a difference at all. An Openreach engineer will be able to verify that as he has a device which he will connect to the master socket and will measure your estimated speeds.

I had an engineer come for my FTTC in February to install a VDSL Faceplate which has a pre-built filter that way you won't need separate micro filter. This can improve speed performance and reliability under FTTC. My estimates according to his device were between 70-83Mbps. And indeed I get Full 80/20Mbps speed under router and speed tests with TalkTalk.

I will get these done and uploaded shortly however I've just discovered that they do already have FTTC but with an ADSL filter inline with a HH6 and there sync speeds 3.8/0.8.

I'm just trying to find out more info but I'm doing it remotely and they aren't that clued up on everything, I'll report back shortly.

OK, I now have a bit more info.

It appears they do have FTTC already and are using an ADSL filter (tried a couple of different one) with a HH6.

The details from the checker for their house are
https://drive.google.com/file/d/1jVjy0WajHxazYcS-Qyq...

And the details for one of the other houses connected to the same pole are
https://drive.google.com/file/d/1w7eC0fVS5l5_MiOkS8I...

All but one of the other houses connected to the same pole are the same, the other is about 65/15.

They've just tested the connected with nothing plugged in except for the HH6 via an ADSL filter and the technical log shows the connection speed is about 3.8/0.8 and the max connection speed is about 5/1.

I'll get a copy of the technical log posted shortly when they send it through.

Are ADSL filters the same as the NTE5 faceplate filter? (I appreciate the NTE5 is the better option.

They've just done a 17070 quiet line test and they described it as 'Like trying to listen to the top 10 in 1982'.

Hopefully that means they can report it as a fault and when they look at that it will also sort the fibre speeds out too.

The hand back speed is 7.9, and along with the quiet line test, presenting noise, i'd raise a voice fault, along with a low speed fault. Not sure which isp your parent's are with as that may impact in how you ask get something done.

If you could be there at the day of the engineer that would help the situation, hopefully they will do a dp test so to isolate the issue as being the house wiring

My friend is with BT if that makes a difference and I think the voice and low speed fault is the way forward and then see what they say on the day about the wiring.

I believe all wiring and sockets has been done previously by BT.

Here are the stats from the router.

https://drive.google.com/file/d/1kaNVG22mx4FTdwSuVSD...

Edited by StuB (Tue 25-Aug-20 13:33:52)

In reply to a post by BLaZiNgSPEED:

You can try joining an ISP like Vodafone FTTC that would install a new telephone line for free which will eliminate all the internal wiring issues.

If a migration they will use the existing line just like any other provider.
An engineer won't necessarily visit the property either.

It is unlikely that 17Mbps is the highest attainable speed under FTTC even with a 1km long cabinet for example.

At the very least 24-30Mbps should be receivable under FTTC. If those estimates are low then your line should not make much of a difference at all.

Do you just make this stuff up as you go along or are you reading this nonsense somewhere?

The longer the line, the lower the sync.
There isn't some magical distance where the minimum you receive is 24-30Mbps.

Where did you pluck 24-30Mb from anyway? What makes you think FTTC provides at least that figure? It does not.

FTTC can give considerably lower than 24Mb.
I've seen FTTC give 4Mb sync and the customer was thrilled with that as it was x4 what ADSL was providing.

if the user is receiving 17mbits, on adsl2, they are either exchange lines or just very close to the exchange, thus any fttc cab should give very good vdsl speeds unless they rerouted the cab via the sticks.

Any DP speed test will sort out if it is the cabling from the dp to the "socket".

ADSL filter should not cause a massive drop in speeds, basically doing the same job, unless it was a cheap and nasty eBay one, which can be particularly poor

You say filter, so just the router and a phone plugged in? Absolutely nothing in the house connected to the phone line e.g. sky box, ringer, other phone? What about extension wiring.

https://www.bt.com/help/landline/getting-set-up/cost...

If no one locally is up to figuring out the issue, link shows pathway to getting someone to do it commercially.

The checker is going to be showing low due to the feedback systems, i.e. real world data over time will override the checker estimates. Fix the in home issues and sync will improve.

Cabinet 6 is near to the phone exchange.

In reply to a post by j0hn83:

In reply to a post by BLaZiNgSPEED:

You can try joining an ISP like Vodafone FTTC that would install a new telephone line for free which will eliminate all the internal wiring issues.

If a migration they will use the existing line just like any other provider.
An engineer won't necessarily visit the property either.

It is unlikely that 17Mbps is the highest attainable speed under FTTC even with a 1km long cabinet for example.

At the very least 24-30Mbps should be receivable under FTTC. If those estimates are low then your line should not make much of a difference at all.

Do you just make this stuff up as you go along or are you reading this nonsense somewhere?

The longer the line, the lower the sync.
There isn't some magical distance where the minimum you receive is 24-30Mbps.

Where did you pluck 24-30Mb from anyway? What makes you think FTTC provides at least that figure? It does not.

FTTC can give considerably lower than 24Mb.
I've seen FTTC give 4Mb sync and the customer was thrilled with that as it was x4 what ADSL was providing.

Ok, so this is where my figures are coming from.

Superfast (>24 Mbps): 96.78%
Superfast (>=30 Mbps): 96.44%

Less than 4% of FTTC customers actually receive speeds lower than 30-24Mbps. I can now see the screenshot that the OP has captured and indeed I am dismayed at seeing the 17Mbps as the maximum. I initially thought this was mistaken for an ADSL service because this is the first time I have seen such low speed estimates.

This signals that there must be a defect somewhere that causes speeds to sync to this low. You've said it yourself before and others have in the past about my concerns with FTTC that if millions of customers are using such a service happily what is there for me to worry about?

That is when I got upgraded to FTTC last year. Fortunately for me I do get the top speeds and service has been very reliable unlike ADSL in my case when I was on EO Line previously. But no one expects FTTC to be less than 24Mbps, because the whole purpose of FTTC is to promise you speeds much faster than that, or otherwise what would be the point?

If the OP can't get above 17Mbps, it is as if he has ADSL instead! If there is a line fault inside the property then either Openreach will have to find the problem, but they generally will charge you if they find the fault in your property. If this is the case, then my proposal is to try a new line. Now maybe due to Corona period, engineers might not visit the property. But I have in the past many years ago managed to get an Openreach engineer to install me a new line when I had a lengthy line traveling under my carpet and it was causing problems. I managed to get a new line at that time with new socket as I now have laminate flooring. Perhaps my case was an exception.

I also got an engineer to visit my flat in February when I first upgraded to FTTC and the Openreach engineer installed a new NTE5C filtered faceplate free of charge as part of my FTTC upgrade.

It doesn't seem quite normal to see that the user is connected to the same cabinet as someone else but has drastically different speeds. Usually the speed checker would show similar speed estimates for the same post code under the same cabinet.

It wasn't a comment specific to the OP but a generic statement about FTTC.

He regularly posts such nonsense.

The filter would have been the one originally supplied with BT at some point, probably a few years ago.

They also tried a spare but that resulted in the same.

The stats I posted were with nothing plugged into the downstairs socket except for an adsl filter and the router.

The only exception to that is the line is split just after it joins the house at the eaves and I believe the other cable runs to another extension upstairs. There is nothing plugged into this extension and it is unused.

https://drive.google.com/file/d/1ceOEIh0Fs2-bOOfZpw8...

I presume disconnecting the upstairs socket wiring wouldn't help unless it was also disconnected at the junction box at eaves.

There is also a BT box in the house that I assume is a junction box that is between the line coming in and the downstairs socket.

https://drive.google.com/file/d/11lQjnKEOYSpNYEwYFKq...

With this setup what wiring is owned by BT and what is owned by the home owner. I'm pretty sure all wiring will have been installed by BT in the past.

Thanks for the link for getting help from BT.

I'm guessing that this wiring will have the ring wire still connected, any value in trying to disconnect this as I know this sometimes helped on older ADSL connections.

They thought they were on ADSL but it appears they are actually on FTTC already and as per the stats upload I've posted in another post they get about 3.8 down and 0.8 up.

There must be a fault somewhere either inside or out.

In reply to a post by BLaZiNgSPEED:

I initially thought this was mistaken for an ADSL service because this is the first time I have seen such low speed estimates.

There are plenty of other examples in this forum. There was one example where someone was on (I think) 9Mbps ADSL, and BT force-migrated them to VDSL, and they ended up with a lower speed. This is part of BT's strategy for phasing out ADSL and LLU, but unfortunately a minority of people end up with a worse service.

In reply to a post by BLaZiNgSPEED:

This signals that there must be a defect somewhere that causes speeds to sync to this low.

Not necessarily. It could just indicate that they are a long way from the cabinet.
https://www.increasebroadbandspeed.co.uk/2013/chart-...

ADSL uses the low end of the frequency spectrum which carries best over long distances. To avoid interference with ADSL, VDSL uses higher frequencies (2.2 MHz upwards I think). Higher frequencies suffer higher attenuation - that is, the attainable speed drops off faster by distance. G.Fast uses even higher frequencies, and hence even worse performance at long distances.

In reply to a post by BLaZiNgSPEED:

No one expects FTTC to be less than 24Mbps, because the whole purpose of FTTC is to promise you speeds much faster than that, or otherwise what would be the point?

If you were 5 miles from the exchange and were getting 0.2Mbps on ADSL, and then found yourself 2 miles away from an FTTC cabinet and getting 10Mbps on VDSL, you'd probably be very happy with the improvement. This does happen.

In reply to a post by BLaZiNgSPEED:

It doesn't seem quite normal to see that the user is connected to the same cabinet as someone else but has drastically different speeds. Usually the speed checker would show similar speed estimates for the same post code under the same cabinet.

I agree (excluding the case where adjacent properties are going to different cabinets).

The noisy line here is the give-away. It seems there is a copper fault which is reducing the speed; the availability checker responds to actual measured sync speed, and reduces its estimates accordingly.

So the number one issue is to raise a noisy line fault with the telephone provider - who may or may not be the same as the broadband provider. The rectification of that will probably solve the problem entirely. The bridge tap issue is secondary and may give a small additional speed boost.

Edited by candlerb (Tue 25-Aug-20 15:33:05)

In reply to a post by BLaZiNgSPEED:

Ok, so this is where my figures are coming from.

Superfast (>24 Mbps): 96.78%
Superfast (>=30 Mbps): 96.44%

Less than 4% of FTTC customers actually receive speeds lower than 30-24Mbps. I can now see the screenshot that the OP has captured and indeed I am dismayed at seeing the 17Mbps as the maximum. I initially thought this was mistaken for an ADSL service because this is the first time I have seen such low speed estimates.

Those are the percentages for the whole of the UK via various networks and technologies, not just FTTC.
That figure includes everyone who gets less than 24Mb/s on FTTC but has Virgin or an Alt-Net present.
.
OpenReach only 30Mb/s+ coverage is actually 91.63%.
It's on the same page you plucked those figures from.

Just because the majority might receive a certain figure doesn't mean you should post such a generic comment as

At the very least 24-30Mbps should be receivable under FTTC.

.

Everyone on FTTC who gets less than 24-30Mb would disagree.
That could well be more than 4% of FTTC customers.

But no one expects FTTC to be less than 24Mbps, because the whole purpose of FTTC is to promise you speeds much faster than that, or otherwise what would be the point?

Yes, many do expect that.
The point is if you live in the middle of nowhere and get 1Mb ADSL you would be doing backflips to get 20Mb/s from FTTC.

The point is the majority on an FTTC cabinet will probably get 24Mb/s+ but there will be some customers on a cabinet who live too far away to get that speed.

You seem to be assuming FTTC is designed to give everyone SuperFast speeds.
If I live 2km from the cabinet and will only get 10Mb/s then should they not bother upgrading my cabinet to FTTC... because what's the point?
You're ignoring everyone else on my cabinet that would get SuperFast speeds.

Everyone doesn't live in a city centre near an exchange like you.
Many are miles from the exchange so get terrible ADSL.
Many are also miles from their FTTC cabinet and get under 24Mb/s. They still appreciate the uplift in speed FTTC brings.

Such generalised statements simply spread misinformation.

In reply to a post by StuB:

Here are the stats from the router.

https://drive.google.com/file/d/1kaNVG22mx4FTdwSuVSD...

G_993_2_ANNEX_B is VDSL2 so they are on FTTC.

This agrees roughly with the "max observed speed" on the checker of 4.53 / 1.08

Since the downstream handback threshold is 6.8M this could be raised as a broadband fault, but really I suggest raising the noisy line fault first. If the phone and broadband are from the same supplier, then a single fault should cover both.

Both voice and broadband are with BT and raising a voice fault first and broadband second is exactly what I've told them to do and they're starting that process now.

One way or another they'll hopefully get it sorted.

In reply to a post by j0hn83:

But no one expects FTTC to be less than 24Mbps, because the whole purpose of FTTC is to promise you speeds much faster than that, or otherwise what would be the point?

Yes, many do expect that.
The point is if you live in the middle of nowhere and get 1Mb ADSL you would be doing backflips to get 20Mb/s from FTTC.

The point is the majority on an FTTC cabinet will probably get 24Mb/s+ but there will be some customers on a cabinet who live too far away to get that speed.

You seem to be assuming FTTC is designed to give everyone SuperFast speeds.
If I live 2km from the cabinet and will only get 10Mb/s then should they not bother upgrading my cabinet to FTTC... because what's the point?
You're ignoring everyone else on my cabinet that would get SuperFast speeds.

Everyone doesn't live in a city centre near an exchange like you.
Many are miles from the exchange so get terrible ADSL.
Many are also miles from their FTTC cabinet and get under 24Mb/s. They still appreciate the uplift in speed FTTC brings.

Such generalised statements simply spread misinformation.

Ok, so here's the confusion. When I posted the exact same link https://www.increasebroadbandspeed.co.uk/2013/chart-... that candlerb just posted in response to my post. You said last year that these were far too pessimistic estimates and that you were getting 45Mbps on a 1km line.

This is when I expressed my concern about what speeds I was going to get when I got upgraded to FTTC last year from an EO Line.

I was told that most people are connected to a cabinet that is between 300-500 meters so it should give them top speeds and indeed I am lucky I get max speeds.

I was getting terrible ADSL formerly on EO Line, even though it was 12Mbps it was constantly dropping out due to noise on the line. FTTC in my case completely solved the problem, I am now syncing at max speeds without drop-out last 6 months since switching to FTTC. Perhaps I am lucky to live in the city centre, but I still had to wait over 10 years just to get upgraded to FTTC from an Exchange Only Line! And that EO Line was quite problematic given that I live in urban Central London.

But in the case of the OP, we can see that his max ADSL is 14Mbps but FTTC is only marginally higher at 17Mbps and is getting drastically different speeds to that of another user on the same cabinet. Something is not right here and even candlerb agrees with me.

This comparison https://drive.google.com/file/d/1jVjy0WajHxazYcS-Qyq... vs https://drive.google.com/file/d/1w7eC0fVS5l5_MiOkS8I...

In this particular case, OP says that the other houses connected to the same pole but getting the top speeds and that's assuming that there isn't a very big distance to the same Cabinet number 6. Then we can rule out cabinet distance in this case since without the added noise it cannot explain why they are getting 67-80Mbps and 17Mbps for the OP.

That to me does not look like anywhere near 1 or 2km distanced cabinet. Maybe the OP can clarify on that, assuming that the other house getting 67-80 Mbps isn't too distant away from the house he's living in.

So this indeed seems like a noisy line fault. Because if distance was the problem, that can't explain how a house near him connected to the same cabinet can get 67-80Mbps that looks more like a few hundred meters to the cabinet rather than miles from the cabinet.

Issue is most likely internal wiring and this introducing noise, overtime high numbers of errors will see the DLM drive sync speeds down until a stable relatively error free speed is found.

Needs someone to visit and resolve wiring and if that does not offer improved sync speed to look at the external line.

In reply to a post by BLaZiNgSPEED:

Ok, so here's the confusion. When I posted the exact same link https://www.increasebroadbandspeed.co.uk/2013/chart-... that candlerb just posted in response to my post. You said last year that these were far too pessimistic estimates and that you were getting 45Mbps on a 1km line.

No confusion.
Those estimates (on average) are a little on the pessimistic side (in my opinion).
That means many will get higher that those estimates for their distance, many will get near those estimates, but some will also get less.
Every line is different.

You see the bottom of that chart? At 3km you can expect around 8.7Mb.
So because I said the chart is pessimistic that means that 8.7Mb becomes 24Mb?!?!? No?
What's the relevance of me saying that chart is a little pessimistic?

You were overly paranoid about what speeds you would receive with VDSL.
You provided your location and were advised not to worry and that you would receive good speeds.
You did.
I don't see the relevance with that either though. Nobody mentioned your line.

But in the case of the OP, we can see that his max ADSL is 14Mbps but FTTC is only marginally higher at 17Mbps and is getting drastically different speeds to that of another user on the same cabinet. Something is not right here and even candlerb agrees with me.

Everyone in the thread can see that.
I haven't commented on the OP's line at all. I've certainly not said everything with it is fine.
Part of the reason you were assured you would get good VDSL speeds is because you had good ADSL speeds.
It is very very rare that a high syncing ADSL line will get less on VDSL.

I was simply pointing out that your generic statement about VDSL providing at least 24-30Mb was incorrect and misleading.
You appear to have accepted that is indeed the case.
So why are you still debating it?

This has gone way off topic and isn't very fair to the OP.

In reply to a post by BLaZiNgSPEED:

That to me does not look like anywhere near 1 or 2km distanced cabinet. Maybe the OP can clarify on that, assuming that the other house getting 67-80 Mbps isn't too distant away from the house he's living in.

So this indeed seems like a noisy line fault. Because if distance was the problem, that can't explain how a house near him connected to the same cabinet can get 67-80Mbps that looks more like a few hundred meters to the cabinet rather than miles from the cabinet.

Just to clarify as mentioned in another post after checking further their current line is actually FTTC and the actual connection speed is 3.8/0.8.

The other properties with an indicated 80/20 are connected to the same pole and are just the other side of the road.

I think the green box is right outside the exchange and the exchange is less than 200m away.

As MrSaffron ad others have mentioned in this case it's likely there is a fault and it's been raised with BT now.

It's easy to forget what has already been discussed:-

In reply to a post by StuB:

It looks like the overhead cable comes from the pole to the eaves of the house where it goes to a small box before being split into two wires each going to an internal phone socket. Only the one socket is used nowadays.

Although the BT Wholesale estimator says there is no bridge tap, it would seem there is. Possibly not detected due to the absence of an NTE5. (Unless that is on the unused "extension").

Added to the noisy 17070 test, it does seem sensible to get that fixed first. A callout for it could well result in any wiring problems being fixed if there really is no NTE5.

To my knowledge the upstairs unused extension is not an NTE5 socket either.

Good .

Just as a quick follow up to this, they reported the voice fault and an engineer visited this morning which I thought was a pretty quick response.

The engineer tested the line at the internal junction box and declared the line quality to the exchange as good and said he believed the fault was with the old socket so he has fitted them a new master socket and tidied up the cabling from the internal junction box to the socket.

He was told about the junction box on the eaves and the extra line taken from it but he didn't look at either and thought they weren't a problem as from the internal junction box his tester said the connection was good and that was enough for him.

After replacing the master socket and they checked that the broadband speeds which were still slow and he left saying try that for a week or two and see how it goes.

They've just sent me a copy of the technical log from the router and it looks like it's done nothing, and the speeds have actually reduced further to 3.4mbps down.

https://drive.google.com/file/d/17x5cktph7ZS1kpJqhyD...

The 17070 quiet test is still a bit fuzzy but it's possible the phone they are using is old and not the best.

I'll drop them off another router and lead to test with just to make sure that it's not a problem with their router but I think it's going to have to now be reported as a broadband fault which hopefully they will investigate as the speeds are lower than the hand back speeds.

So is the money on the bridge tap and upstairs extension being the problem or the fault being further upstream?

(Your Google Drive link is protected)

If the neighbours are achieving 80Mbps, I don't think a bridge tap will reduce from 80M to 3.4M.

If the ISP provided a router, use that one while the fault is being investigated.

Sorry about the link, it should work now.

Main takeaway is line attenuation has gone from 39.6db to 39.1db.

Thanks for your thoughts on the bridge tap and extra line.

They are using their ISP provided router, a BT Home Hub 6. I have a spare HH5 that I can lend them so I'll drop that off for them to try.

Edited by StuB (Thu 27-Aug-20 16:16:05)

Just a thought: such a drastic loss of speed can be seen if one of the two wires in the circuit is broken.

Can you try with a different cable between the master socket and the router?

If that doesn't work, then as you say, try with another router (because a pin or PCB trace might have broken inside the router itself)

When I drop them off another router I'll drop another cable off too and tell them to try that first.

I would normally have popped around and tried a different router and cable first however they are shielding due to covid and health issues with one of the house occupants hence trying to fix this remotely.

I''m surprised they didn't meet the engineer in a full hazmat suit

In reply to a post by candlerb:

Just a thought: such a drastic loss of speed can be seen if one of the two wires in the circuit is broken.

If a single wire of the pair is broken the phone wouldn't work at all. But the broadband would behave as you say.

The second wire from the box under the eaves still sounds not ideal, and if the contacts inside that box are corroded, affecting either or both pairs that too would be a factor.

The line is still on ADSL2+ as far as I remember, originally at 17Mbps. That would tie in with a detached or perhaps corroded terminal) wire of the pair.

Hopefully they'll check the cable in the next day or so but are you saying that adsl and vdsl can still function with just one wire of the pair connected?

If so I didn't realise that.

Also I did post in one of the updates that it turns out they do actually have FTTC and they current;y get about 3.4 down and 0.8 up.

Ah, yes. I remember that now.

Yes, xDSLx can work with just one wire connected. I'm not sure whether or not it depends which one of the pair is still connected.

This seems more likely to be a fault in the fibre cab, anything from a duff port on the card to a faulty or not fully inserted filter and anything in between.

In reply to a post by RobertoS:

Yes, xDSLx can work with just one wire connected. I'm not sure whether or not it depends which one of the pair is still connected.

I'm really surprised about that, my logical head says that shouldn't be possible and that the two wires are needed for a circuit but clearly not.

In reply to a post by StuB:

In reply to a post by RobertoS:

Yes, xDSLx can work with just one wire connected. I'm not sure whether or not it depends which one of the pair is still connected.

I'm really surprised about that, my logical head says that shouldn't be possible and that the two wires are needed for a circuit but clearly not.

I think it's less of a circuit and more of a waveguide, adsl2+ used to be pretty much the same frequencies as AM radio and VDSL is much the same idea but over a larger Freq range (different modulations as well I think).

On short lines it's indeed possible to get sync with one leg dis (just don't expect it to work well)

In reply to a post by StuB:

In reply to a post by RobertoS:

Yes, xDSLx can work with just one wire connected. I'm not sure whether or not it depends which one of the pair is still connected.

I'm really surprised about that, my logical head says that shouldn't be possible and that the two wires are needed for a circuit but clearly not.

Think of your TV coax cable or for that matter Virgin Media coax or a satellite coax, there is only a single conductor. It’s the same deal with other forms of cabling, not just coax for passing communications signals.

A “circuit” is only needed for DC in the case of traditional telephony or AC power supply. Not for comms strictly.

This all harks back to transmission line theory 101 for budding electrical and communications engineers

Thanks for the education and what you say makes sense.

Just a quick follow up on this, they had another BT engineer out the other day to look at the broadband and while I don't know the full details I believe he changed the wiring from the eaves to the master socket and presumably removed the bridge tap for the upstairs extension and they now have a full speed FTTC connection.

Thanks everyone for your help, it's much appreciated.