VDSL Attenuation and Slow speeds

Looking for a bit of advise here,

Just ordered a VDSL service at an address that the BT DSL Checker predicts a speed between 55 and 73mbps

Service was activated yesterday and the sync speed is 16mbps - clearly very poor

The BT HomeHub reports a line attenuation of 31/22.9dB

I found an attenuation to sync speed calculator for VDSL2 and it predicted a sync of 18mbps based on this attenuation, does that sound accurate?

Having tried BT "Technical" help they had no idea what attenuation actually was and suggested I wait a month before contacting them again. Clearly I don't want this to drag on past the cooling off period as I don't want to be stuck in an 18month contract for a service that performs so poorly.

Screenshot of Sync Speed: https://imgur.com/a/yq37l

Any ideas?

Yes, that does sound about right. But, either your line is faulty, or the checker is wrong. Do you know how long your line is (have you traced it to the cabinet)?

Could you describe its set up within the property please ?

Is it on an extension, or is there extension wiring connected unfiltered to the NTE ?

Need to know how long his line length is, before we go into trying to fix it...

I can see the cabinet, it's on the same road as my house.

I now know the line is faulty, just went out and picked up an analogue phone and the line noise is so high you can barely hear the dial tone.

When you can hear the dial tone it's very intermittent

BT live chat were next to useless insisting that despite this the line didn't show any faults and this was normal during the "Stabilisation" period.

I managed to get an Openreach appointment by being very firm with the agent who really didn't want to send one out.

Unplug all the broadband hardware and if the phone is still bad, get that reported and fixing that dodgy connection/wire is likely to improve the broadband

NOISE ON THE PHONE WHEN ALL BROABDAND KIT IS UNPLUGGED IS NOT NORMAL

In reply to a post by MrSaffron:

Unplug all the broadband hardware and if the phone is still bad, get that reported and fixing that dodgy connection/wire is likely to improve the broadband

NOISE ON THE PHONE WHEN ALL BROABDAND KIT IS UNPLUGGED IS NOT NORMAL

Done that, hence the "I now know the line is faulty"

For context the set up is line in - Old BT JB - NTE5 - BT Hub

nothing else int he house, noise is present at all times and it is very bad. Openreach are coming on Monday despite BT customer Services best efforts

I wonder if the pinhead who did your cab jumpering has ballsed it up ?

Badly terminated PC100 connection ....

If it�s testing OK, then they will most likely have raised a CDTA task (conscience decision to appoint) come in, PQ test and that is sometimes that. MAKE SURE you see and hear them test the dial tone for noise. They should then use the TDR function on their tester to measure to the HR.

Slightly off topic but when I upgraded to FTTC, the person that did the upgrade somehow managed to unplug my line and I could hear someone's phone calls and getting their calls on my line but internet side was fine. Was very strange.

Reported the fault but an OR engineer knocked on my door asking if my line was working, unrelated to what he originally went to the cab for.

Yes, I've heard about a few of these issues. It's because the broadband (D side) is connected just to the cabinet, whereas the telephony (E side) is connected all the way back to the exchange, so they're entirely seperate. AFAIK, both the D and E side on ADSL, are both connected the same way, so if the E side is affected, the D side is too. Correct me if I'm wrong.

Edited by deleted (Fri 01-Dec-17 21:03:07)

On a simple basis, as originally wired, the E-Side and the D-Side are connected "straight through" in the PCP Cabinet.

The ADSL connection/feed is done directly within the Exchange, with no changes to the PCP wiring.

So still straight-through the PCP.

--------------------------

For most VDSL connections, the equivalent to the ADSL Exchange equipment is provided in the (new) FTTC, with Fibre from the Exchange (or even another Exchange) providing a multi-path, high speed link to the Web.

Link cables are also added, between the FTTC and the PCP - connected etc to individual feeds in the FTTC - but NOT connected in the PCP.

As each individual subscriber chooses to upgrade to VDSL, the PCP straight-through E-D connection is broken.

The E-side is then connected to one pair of Link Wires to the FTTC; followed by the D-side being similarly linked to the FTTC, thus picking up the VDSL signals.

So the routing is now-

Exchange (for phone etc) ~ Existing E-Side to PCP ~ PCP via E-Side Link to FTTC ~ VDSL ~ FTTC to PCP via D-Side Link back to PCP ~ PCP via existing D-Side to house.

The modified D-Side carries both VDSL and traditional phone, alarms etc

The modified E-Side carries the traditional phone, alarms etc - no VDSL.

Thus it is easy to get wires mixed up, bearing in mind that there are hundreds of them, take a close look the next time you see a PCP being worked on - in the cold and wet or hot and dry.

There are minor complications; but better not mentioned at this stage.

Edited by deleted (Sat 02-Dec-17 07:08:10)

If that happens again, hopefully unlikely, try ringing 17070 and listen carefully to the Phone Number - it probably would have been for that other line.

17070, if available, also gives you access to the Quiet Line Test, mentioned frequently.

Worth being aware of it and the implications of any noises etc heard.

I did use 17070 and it did have the other persons phone number, Sky support told me to do that after I explained the fault.

Did some Googling when it first happened and came across another person who had a very similar problem, he was unlucky though and I believe his line was crossed with the his local (And very busy) Chinese takeaway

Ah, interesting. Thanks for the in-depth explanation.

So, I had an OR engineer round on Saturday, no more noise on the line but speeds are still below prediction.

I have left the line a few days before digging deeper but I'm still not overly impressed with performance.

Line length is about 300m and DSLChecker predicts between 53 and 74 but I'm only seeing 40 on a good day, pictures are attached, what does everyone think?

https://imgur.com/a/N1AqO

A split pair, or faulty port perhaps.

It might be worth trying to get them to book a Broadband Boost engineer, if you're quite sure it's nothing at your end.

PS That cabinet is definitely not PC100 inside.

Edited by troublegum (Wed 06-Dec-17 23:13:55)

In reply to a post by troublegum:

A split pair, or faulty port perhaps.

It might be worth trying to get them to book a Broadband Boost engineer, if you're quite sure it's nothing at your end.

PS That cabinet is definitely not PC100 inside.

I think I may do that.

Nothing at my end, modem is plugged directly into the NTE5 Test Port, don't even have a phone let alone an extension connected.

What do you mean by "Not PC100"

�PC100�s are the old screw type cabinet terminations.

Tricky to terminate correctly, especially since they stopped providing the correct gauge jumper wire some years back.

Notorious for 1 leg dis faults.

I'm beginning to think that the cable from the DP to my NTE is bad, it has 3 GPO JB's in it

the DP is right above the front door, so it's not exactly a long run

Though clearly not �good practice�, it�s not always visible bits that are the issue.

those stats seem to indicate a 40/10 service

In reply to a post by ggremlin:

those stats seem to indicate a 40/10 service

I was thinking that, but the max attainable is still below the handback threshold

Almost certainly on 40/10 ... the attainable at 46 is also way below what should be expected from your line. 16dB suggests around about 400m, slightly longer that on the map, and it should have an attainable in the 70 to 80 region but the noise figure at 6dB points to a high noise level. What sort of businesses are there on the way?

In reply to a post by MHC:

Almost certainly on 40/10 ... the attainable at 46 is also way below what should be expected from your line. 16dB suggests around about 400m, slightly longer that on the map, and it should have an attainable in the 70 to 80 region but the noise figure at 6dB points to a high noise level. What sort of businesses are there on the way?

Loads of businesses between the cab and here.

at least 3 shops, 3 takeaways, florist, ice cream place etc.

I'll get onto BT and get them to check if the service is provisioned as 40/10 or 55/10

If i put my address into the bt.com predictor I get a lowest "assured" speed of 49, so event he max attainable is below that

You will find it is 40/10 - the 39.x sync well below the 46 attainable demonstrates that. If you were on a 55/10 then sync would be around 46.

Check your stats hourly, particularly SNR and Sync - do they vary overnight or in the evenings. Get DSL stats running and let it monitor for 48 hours if you can and also use the online facility so we can see your data. That may give some clues.

In reply to a post by MHC:

Get DSL stats running and let it monitor for 48 hours if you can and also use the online facility so we can see your data. That may give some clues.

Does DSL Stats support the Hub 6?

If not I've got a HG612 somewhere I can use

In reply to a post by connormill:

Does DSL Stats support the Hub 6?

No, the Hub6 doesn't work with dslstats

If not I've got a HG612 somewhere I can use

The Hub6 doesn't work with a modem unless you have the FTTP version of the Hub6 with a WAN port.

Edited by deleted (Thu 07-Dec-17 21:55:10)

In reply to a post by BatBoy:

In reply to a post by connormill:

Does DSL Stats support the Hub 6?

No, the Hub6 doesn't work with dslstats

If not I've got a HG612 somewhere I can use

The Hub6 doesn't work with a modem unless you have the FTTP version of the Hub6 with a WAN port.

I'll put the HG612 into my UBNT EdgeRouter and UniFi AP

In reply to a post by MHC:

Almost certainly on 40/10 ... the attainable at 46 is also way below what should be expected from your line. 16dB suggests around about 400m, slightly longer that on the map, and it should have an attainable in the 70 to 80 region but the noise figure at 6dB points to a high noise level. What sort of businesses are there on the way?

It was my understanding that the max attainable was set by the DSLAM and not dictated by the package selected by the ISP.

If thats the case, then is there a reason why the attenuation would suggest 70 attainable but the modem only thinks 46 is attainable?

As I said NOISE ... The DSLAM will keep dropping the attainable rate until the 6dB SNR is reached.

Just dug out an old analogue handset.

No noise on the line when Openreach engineer left last weekend, noise on the line now.

away to report it as a voice fault

So get that sorted, and keep checking. Remember though, that most of te noise affecting VDSL you will not be able to hear. and comes from motors, lights, switches &c.

In reply to a post by MHC:

You will find it is 40/10 - the 39.x sync well below the 46 attainable demonstrates that. If you were on a 55/10 then sync would be around 46.

So this morning I can confirm it's definitely not a 40/10 service, resynced at 44, max attainable still 46 and noise still present on the line.

Openreach visiting tomorrow

I would strongly recommend that you obtain a simple, corded phone, to have available to carry out simple testing, particularly the Quiet Line Test involving phoning 17070 etc, at No Cost.

Also doing the QLT at least once per month, in addition to when you suspect faults.

In reply to a post by eckiedoo:

I would strongly recommend that you obtain a simple, corded phone, to have available to carry out simple testing, particularly the Quiet Line Test involving phoning 17070 etc, at No Cost.

Also doing the QLT at least once per month, in addition to when you suspect faults.

already got that, I have been performing Quiet Line Tests already and there is intermittent background noise on the line

So OR are just away, the JB's have been replaced with Jelly Crimps inside the old JB enclosure, no more IDC connections.

NTE5 replaced with filtered NTE5c

Engineer confirmed line length to Cab is 410m, which should ive speeds of around 65-70mbps.

however, Max attainable is still only 46, but I am now syncing at 45.

Don't get me wrong, a perfectly acceptable speed, but the BT sign up page has a "Lowest assured speed" of 50mbps, above my Max Attainable. The BTW line checker still lists my line as being capable of up to 77.3, something that I can never see happening.

Whilst I'm happy enough with 45mbps, should I keep pushing BT to increase this ro should I just accept defeat and take the 45?

Is the 50 Mb your downstream handback threshold value? If so, then yes you should keep pushing as it looks like what the engineer has done, hasn't improved the speed. I agree with your estimate, my line syncs at or just below 55 Mb (the max for my package BT 55/10) most of the time, and it's circa 900 m long...

Edited by deleted (Sat 09-Dec-17 15:40:16)

In reply to a post by WilliamGrimsley:

Is the 50 Mb your downstream handback threshold value? If so, then yes you should keep pushing as it looks like what the engineer has done, hasn't improved the speed. I agree with your estimate, my line syncs at or just below 55 Mb most of the time, and my line is circa 900 m long...

Handback is 44.7, Sync is 45.1

annoyingly, they just scrape over the line

Ugh, annoying. Try doing a resync in a noisy period, that should work.

The handback is not a guaranteed speed but if it is below the handback speed and BT can't resolve then the contract can be cancelled. So, after lots of pushing the BT response may just be "ok, we'll let you cancel the contract".