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Author Topic: (Not) Smooth as silk on Sky, read on...  (Read 10917 times)

guest

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Re: (Not) Smooth as silk on Sky, read on...
« Reply #15 on: December 20, 2013, 12:46:44 PM »

The annoying thing is that apart from the mother-in-law, the only incoming calls we get on the landline are spam calls. We all have mobiles on the same network (3) so none of us "call home" either.

VDSL works perfectly as long as no POTS stuff is happening.

We'll see what happens when/if Sky call me back this afternoon. I reckon all it needs is the OR guy to go back and remake the crimps and IDC connections in the cabinets. Provided he contacts me at the time then I can tell him when its sorted even if he can't see anything on his JDSU - cabinet is 100m from the front door so its easy-peasy for me to give him feedback in real time. All the cabling around here is underground and we've had 13mm of rain this month so it is unlikely to be moisture/weather related. Dodgy crimp is my bet.
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guest

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Re: (Not) Smooth as silk on Sky, read on...
« Reply #16 on: December 20, 2013, 02:27:22 PM »

Openreach coming around on Monday morning.

I declined a visit tomorrow morning as I don't believe they'll turn up - Saturday before xmas, grief from other half etc?

Helped I could tell the Sky guy immediately when he'd initiated a line test and when he'd finished simply by watching the u/s noise margin (3 sec repeat isn't great but better than nothing).

Now I have to move the filing cabinet for the first time in 9 years. This is not going to be pretty :D

Actually sod it I think I'll ask him to "move" the master socket back to the original location while he's here - he's no doubt going to fit a VDSL faceplate anyway. Would involve cutting two crimps at original location and fit A/B to terminals. 2 minutes and its done. Saves him buggering about with the extra 20m of cabling BT installed in 2000 so you could use a USB modem from the (compulsory) fitted faceplate.
« Last Edit: December 20, 2013, 02:41:53 PM by rizla »
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guest

  • Guest
Re: (Not) Smooth as silk on Sky, read on...
« Reply #17 on: December 20, 2013, 03:45:53 PM »

Not sure this is a good start to the "self-install" era.

21Mbps @ 3dB margin results in 10-15 CRC errors per day for over a year on ADSL.

First ever install on a cab/exchange where engineer doesn't go to premises and its not good - to the extent that remote line tests can drop the u/s noise margin by 16dB.

I can obviously do the diagnostics but frankly if I hadn't been checking the logs on the Sky router I'd never have seen this. A quick check on the Truecall unit/MySky showed all the sync drops were related to POTS stuff.

Perfect line (as far as possible), filtered faceplate (ADSL v1.0) and it goes tits up in implementation.

I think self-install on VDSL is going to be a short lived product.

This is where the BTOR guy has double checked as it the first self-install (ie no access to premises) that he's done and where there is a "techie" EU who knows what is going on.
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BritBrat

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Re: (Not) Smooth as silk on Sky, read on...
« Reply #18 on: December 20, 2013, 04:07:27 PM »

Mine was an enginner install and it went worse than yours.

So I would not rule out self installs yet.
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guest

  • Guest
Re: (Not) Smooth as silk on Sky, read on...
« Reply #19 on: December 20, 2013, 04:28:20 PM »

The thing is that I wouldn't have noticed this if I hadn't been aware of DLM and was checking logs.

First I'd have known was DLM kicking in which will tend to suppress the underlying problem.

We'll see.
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guest

  • Guest
Re: (Not) Smooth as silk on Sky, read on...
« Reply #20 on: December 21, 2013, 06:59:15 AM »

DLM has indeed kicked in, its applied a lot more INP and d/s sync has dropped to 77694.

Fortunately for me its still easy to see the u/s noise margin drop when you call the line.
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guest

  • Guest
Re: (Not) Smooth as silk on Sky, read on...
« Reply #21 on: December 22, 2013, 08:24:40 AM »

No resync during the night so DLM thinks the line is looking OK, which is good :)

That will hold things in the event the BTOR guy doesn't show/has to get another engineer out. Not ideal with no landline phone at this time of year but we have mobiles.
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kitz

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Re: (Not) Smooth as silk on Sky, read on...
« Reply #22 on: December 22, 2013, 11:14:18 PM »

Quote
Openreach coming around on Monday morning.

Good luck and I hope he gets it sorted for you.

Quote
First ever install on a cab/exchange where engineer doesn't go to premises and its not good - to the extent that remote line tests can drop the u/s noise margin by 16dB.

I could be wrong, dont think this is self install related. Ive been there too on a Engineer home install.  My upstream could drop by up to 21dB meaning a resync at just 8-10Mbps on the upstream.  I cant prove it but Im pretty certain that my line fault was 2 separate issues (so was the engineer who coined the term "double whammy").  The upstream EMI like SNR fluctuation I saw seemed to be resolved after replacing some very obvious corroded joints.   The 2nd problem that continued after that was the loss of sync etc when the phone rang.

Im sure Im not alone in noticing that there seems to be a fair amount of lines that were good, but after moving to FTTC they suddenly start seeing upstream SNRm drops during voice related usage.   Theres certainly been a few on these forums that have experienced it.   Convincing BT though is the hard part :/

I will pass on one tip ...  if the engineer says he cant see any records of your resyncs and implies you are making it up.  Its not unusual for the engineers whoosh results/report to not show resyncs that have happened very quickly.   I felt a right fool when one of them was adamant that my line wasnt resyncing...   all I can say is thank goodness for dslstats to prove my point.
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guest

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Re: (Not) Smooth as silk on Sky, read on...
« Reply #23 on: December 23, 2013, 07:16:15 AM »

Well I can show him upstream dropping to 3dB from what is now 15dB margin. I can also show him packet loss at the IP layer which starts when you initiate an incoming call and stops exactly at the moment you hang up. No telephony equipment connected on this side. 100% repeatable.

Likewise I can show him that the VDSL disconnects every time the handset is lifted to make an outgoing call. I can also demonstrate that the margin will increase once a call is in progress. All also 100% repeatable.

If he tries to give me any bs then its not going to end well, I can tell you that ;)

Interestingly someone has just reset the DLM/forced a resync on the line right now. All stats back to where they were on Thursday. 79987/20000kbps 20/22dB on the margins.
« Last Edit: December 23, 2013, 07:22:13 AM by rizla »
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guest

  • Guest
Re: (Not) Smooth as silk on Sky, read on...
« Reply #24 on: December 23, 2013, 08:27:53 AM »

Its fixed. Just required one of the VDSL faceplates to properly terminate the line. SFI engineer says he's seeing quite a lot of this lately and the ISP supplied microfilters don't work properly on high rate lines.

Stats on the line are (in his words) "******* amazing". Zero FEC errors and a noise level he's never seen as low before. He's also never seen a test run for 5 minutes producing zero FEC errors with a line sync'd at max rate/minimum INP.

I pointed him at this site as he's got no idea about locating REIN - says he keeps asking to be trained but it never happens.

Oh and kudos to Sky as putting this through as a "Care" job.

Fingers crossed that his JDSU tests didn't push enough current through something to remake the joint. We'll see.

Oh and my attainable d/s rate is 116Mbps  8)

Edit - oh and FWIW he said the ADSL v1.0 faceplates "don't work properly" with VDSL. I suspect all of this is more down to impedance matching than filter response but without borrowing a spectrum analyser its impossible to say either way.

[Edited for language]
« Last Edit: December 23, 2013, 10:19:34 AM by roseway »
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BritBrat

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Re: (Not) Smooth as silk on Sky, read on...
« Reply #25 on: December 23, 2013, 09:11:48 AM »


Im sure Im not alone in noticing that there seems to be a fair amount of lines that were good, but after moving to FTTC they suddenly start seeing upstream SNRm drops during voice related usage.   Theres certainly been a few on these forums that have experienced it.   Convincing BT though is the hard part :/


Add me to the list :)
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guest

  • Guest
Re: (Not) Smooth as silk on Sky, read on...
« Reply #26 on: December 23, 2013, 10:27:21 AM »

OK as I posted over at Sky forums I have now tested this with :

a) latest BTOR VDSL faceplate;

b) PMF320P-SKY Rev1A (and Rev 0A) microfilter.

The noise margins do not drop with the faceplate fitted.

The noise margins do drop with either of the Sky microfilters fitted. Incidentally they also drop with every other microfilter I can find but I'm not re-testing them as the DLM monster will come to visit over xmas if I do that :P

So there's something in the latest revision of the BTOR faceplate which deals specifically with some troublesome aspect of POTS signalling/etc that wasn't required on ADSL.
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kitz

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Re: (Not) Smooth as silk on Sky, read on...
« Reply #27 on: December 23, 2013, 11:59:35 AM »

Quote
ts fixed. Just required one of the VDSL faceplates to properly terminate the line. SFI engineer says he's seeing quite a lot of this lately and the ISP supplied microfilters don't work properly on high rate lines.

Excellent :D  Im so glad its all sorted for you  :clap2:

Quote
He's also never seen a test run for 5 minutes producing zero FEC errors with a line sync'd at max rate/minimum INP.
Reminds me of what one of the engineers said about my line.   ie there was nothing wrong with my line because it wasnt recording any FECs.  The hundreds of CRCs didnt matter since they could correct themselves.   Just say this did not go down to well with me as I tried pointing out that the line wasnt interleaved and perhaps he misunderstood the difference between CRCs and FECs.      :mad:

Quote
FWIW he said the ADSL v1.0 faceplates "don't work properly" with VDSL.
Suitable point to mention that there was also a bad batch of VDSL faceplates that fail.  These were supposedly from earlier this year and the newer ones should be ok.  Sub-contrators such as Quinns may have a few still knocking around though.

Quote
Oh and my attainable d/s rate is 116Mbps

Fantastic.   You have plenty to play with :)  Since you know that you are first on your cab and very close it would be interesting to record how much this goes down as more users go over to FTTC.   You may not be too bad as iirc you also have cable in your area to soak up some of the demand.

Youre nearer to a cab than me so you may see the effects of x-talk a bit more.   I wasnt the first on my cab as Id left it a while (Sky buying BE was my push).   I started at about 106/37 Mbps and its now down to about 87/30 Mbps.  My SNRm is now down to about 8dB and for the first time (line fault aside) ever Im seeing frequent E/Secs on this line.
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BritBrat

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Re: (Not) Smooth as silk on Sky, read on...
« Reply #28 on: December 23, 2013, 12:27:25 PM »

Quote
Suitable point to mention that there was also a bad batch of VDSL faceplates that fail.  These were supposedly from earlier this year and the newer ones should be ok.  Sub-contrators such as Quinns may have a few still knocking around though.

I may have had one fitted two weeks ago by a Kelly enginner.
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guest

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Re: (Not) Smooth as silk on Sky, read on...
« Reply #29 on: December 23, 2013, 12:40:06 PM »

The thing that freaked him out somewhat was that there were no errors at all on any of the counters on the JDSU. None. He thought the test head had gone again :)

I can't remember the dB/Hz reading he got for noise but it seemed somewhat remarkable to him.

He re-ran the test and got one FEC but that was probably one of the kids turning on the light/extractor fan in the bathroom.

I'm fairly astonished at the noise margins TBH. Wasn't expecting 20dB on both by any means - as I said to you if there's going to be issues then it will be on upstream. Guess I got the mains filtering nailed down tight :)

Re the ADSL v1.0 failures - doubt this was one as it held 21Mbps @ 3dB with an average of 10 CRCs/day. Ignore that bit, misread your post. I think the extra chokes in the latest version of the VDSL faceplate are there for POTS reasons and not REIN. Might give it a few months until they appear consistently online and buy one, have a play and see what the chokes are for.

Re xtalk - its a big PCP, 2x140 (144 surely?) pair cables to FTTC cabinet. Large Virgin presence around here though - mainly due to BT leaving it late on everything from 256kbps ADSL to FTTC. Always amazes me that Braunstone/New Parks (large and very unpleasant council sink estates) got everything from BT before an area like Glenfield which although nearby has a shedload more "disposable income". Virgin, Sky, Be, TalkTalk - they all worked that out years before BT did/does. Eg the next-door neighbour could only get 2Mbps from BT for 3 or 4 years while I had ADSL2+ from Be and then UKOnline (Easynet). tl;dr is I dunno, anyone who wanted "superfast" around here has probably long since moved to Virgin but they may come back now.

The problem for me in measuring attainable rate is this Sky router which does auth via MER. I may summon up the will to do something about that but frankly most of the VDSL2 kit on the market in the UK looks garbage in terms of specs. Fritzbox stuff is solid (7 year warranty/upgrades helps) and I see Draytek still have their fans - and garbage support for anything meaningful. I'll probably do what I did when I first joined Sky - use their kit for a few months then see what's around/what I can be bothered doing.

BTOR SFI was very impressed with some of the stats you guys are pulling out of unlocked BTOR modems - I showed him one and said look at the peaks on the QLN graph, in that case they were radio stations but they could just as easily be local REIN, so you know what to tune to when you're doing a walkabout. I pointed out to him that the usual "tune to 612kHz" advice isn't decent for VDSL - need a small shortwave radio that covers all the way up to the 16m band, or 17.9MHz for those of you who don't have a radio background. Needle in a haystack time unless you can see real-time graphs.
« Last Edit: December 23, 2013, 12:42:58 PM by rizla »
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