Kitz Forum
Broadband Related => ADSL Issues => Topic started by: Wildy on April 23, 2010, 04:38:47 PM
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Hi all,
While trying to sort what seems to be a REIN issue with my connection, I have come across something else which is puzzling me. At good times I can have a noise margin of 10-11 db, (I guess from that the target is 12), and a sync speed of 1088kbps. Then when the noise problems kick in on a night, noise margin plunges down to 2 or 3 db, frequently causing disconnections too, but after these it still always resyncs at 1088 kbps.
Today I've managed to get my old netgear router running on my sky connection, and after installing the DGTeam firmware, used the option to change the noise margin, but the margin just drops to 0 for a second then comes right back up to 11db, sync speed 1088kbps.
I may be wrong (and frequently am) but it seems to me that I'm somehow locked at this value of 1088 kbps no matter what I do. Feels like I'm getting the worst of both sides since when there's noise I disconnect regardless of the high snrm target, and when there isn't I'm stuck at 1088 with a big, unnecessary margin.
Anyone out there have any suggestions I can try to improve this?
Cheers
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Hi
could you post your your line/router stats (http://www.kitz.co.uk/adsl/frogstats.php) to give us a complete picture of your connection.
It may also be useful to try routerstats (http://www.vwlowen.co.uk/internet/files.htm), this is a useful trouble shooting tool.
Regards Jeff
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ADSL Link Downstream Upstream
Connection Speed 1088 kbps 416 kbps
Line Attenuation 55.0 db 31.5 db
Noise Margin 10.1 db 23.0 db
Stats above were taken while plugged in to the test socket (at a time of no apparent noise issues). Now I'm not stuck with the tamper-proof Sky box, is there anything else useful I could post up? Have got routerstats running ok now.
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I may be wrong (and frequently am) but it seems to me that I'm somehow locked at this value of 1088 kbps no matter what I do.
It would be theoretically possible (though rare) for BT to cap your connection speed at the DSLAM in the exchange, so that the router never synced above a certain figure, regardless of the target SNR. But I cannot imagine (* see below) any mechanism whereby BT could force your router to connect at a faster speed than it wanted to, so I (like yourself) would expect to see a drop in connection speed when the router reconnects after the SNRM decays to nearly nothing-ish.
Best approach is probably to treat it like any other interference issue, and disregard that apparent anomaly for now....
My only comment on the stats you've posted are that you should probably be doing better. If I were you, I'd follow Jeff's advice to get routerstats up & running.
7LM
EDIT: *** UNLESS, of course, you're on fixed rate service. I wonder if a fixed rate profile of 1088 exists?
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@ 7LM,
The Tiscali 1 Meg Rate Cap is 1152 kbps if that's any help.
Kind regards,
Walter
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Hi
@wildy with your attenuation you should be Synching at about 3680 if you are on ADSL1 8max.
If your target SNR margin is 12db then this could be costing you up to 2400 Kbps
What package are you on ?
What is your ISP?
Can you monitor you SNR margin with RSfor a period including the drop and resynch and post the results .
I don't think you are on a 1 meg package as your US synch is 416 Kbps which looks ok for your upstream attenuation for a 8max connection (448 Kbps) .
Regards Jeff
edit oops missed the reference to sky :-[
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I notice you said Sky - who have their own profiles.
Im not sure if they have a 1Mb fixed rate but their 2Mb fixed is certainly different to other ISPs at a measly 2048.
416 upstream is one of their profiles.
Sky have their own DLM, and like BTw it is possible that they may have fixed rate downstream 0.5Mb, 1Mb + 2Mb profiles that can be used in order to stabilise a line.
If it never ever does change from 1088 then this could be the case. Try grabbing a copy of routerstats to record your line stats over a period of time.
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Sky broadband base package = 2Mbps downstream 416Kbps upstream. Sky broadband everyday package = 10Mbps downstream 416Kbps upstream. Sky broadband unlimited package = 20Mbps downstream 1Mbps upstream. Sky do have there own DLM process which if your connection has been dropping out during that 10 days your sync speed has adjusted itself to the speed you are getting now turning it into a fixed rate!. What you need to do is get in touch with sky while your in the test port. If you are having REIN issues and you know REIN is around there but do not know what it is causing the REIN fault then sky can process this to BTW however you will have to have an SFI come out first who will then pass to a REIN engineer if he feels REIN is the case causing the drop in SNRM. Make sure everything else has also been eliminated ie router, filters, RJ11 etc. Anything you think could be causing a REIN issue eliminate it by switching it off and monitoring.
Regards
Gary
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Thanks for all responses so far, Have set up Routerstats for the last couple of days, but haven't had any problems yet.
To fully answer Jeff's question, I'm on sky's medium package (up to 8 meg, some download limit I don't think we've ever come near to hitting)
Looking through some old files I found this, taken from RS lite if it's any help.
Cheers
Wildy
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Well, having had routerstats running every night since starting this thread I've not seen any sign of the noise and disconnections I was originally complaining about, maybe the Sky router was to blame?
However I seem to be finding more questions the more I look into this. Looking at the router now shows
Down Up
SNR (dB): 10.9 24.0
Attn(dB): 55.0 31.5
Pwr(dBm): 17.3 12.3
Max(Kbps): 1568 1056
Rate (Kbps): 1088 416
The max down rate earlier tonight was over 2k, til I tried to restart the router and see if it would resync higher, at which point it came back up with the above figures and continues syncing at 1088k. How is this max rate calculated? Could it's increase be a result of the fairly steady connection of the last week or so?
Also a quick ask around of a few neighbours suggests the entire street is getting no more than 1 meg. I'm pretty certain the distance suggested by the router attenuation is right (a smidge under 4km) so is there something that could artificially limit a whole area like this? (These houses were newly built about 4 years ago and as far as I can tell have always had poor speeds).
Thanks yet again,
Wildy
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AFAIK, the 'max' reported by Netgears isn't documented anywhere, but it seems to be just an extrapolation of the actual speed and the actual SNRM, to indicate what could be achieved if the router reconnected with nothing (high target margins, or caps), to impede it.
I may be wrong, but it seems to me like you have two problems, which have to be tackled in sequence...
1): You have some kind of interference on your line, that renders it incapable of achieving the rates it ought to be capable of.
2): Because of (1), you have been placed on a fixed rate of 1088 (download). After resolving (1), this may resolve itself, otherwise, complain to Sky, but until (1) is fixed there's no point in complaining.
One way to tackle (1) is with Routerstats. If RS doesn't shed any light (and sometimes it doesn't) there are other things that can be tried,, but it's best to start with RS. regardless of whether you had any actual problems whilst sampling, RS may also indicate whether you had any 'near-misses, which can yield valuable clues.
That said, have you actually optimised your wiring yet? I also have attn of 55dB, and used to get about 1 to 1.5 mbps. After disconnecting the ring wire, and a few other minor mods, that increased to 4 to 5 mbps.
It's interesting, mind, that the entire street is suffering similar problems. I lived in a new build estate myself some years ago (pre-adsl, late 90's), where the service wiring installed by the builders was so bad that bedside clocks ran fast and washing machines stopped working sometimes, caused by arcing in the street-light wiring. Any chance it could be related to the on-time of street-lights? There are many things builders can screw up until they're adopted by the Councils.
- 7LM
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Thanks 7LM,
First off the wiring is through a filtered faceplate, so should be no problem, I have also had filters on everthing anyway (one of sky tech supports ideas) and, I believe, also had the same problems when going straight through the test socket behind the faceplate.
1): You have some kind of interference on your line, that renders it incapable of achieving the rates it ought to be capable of.
2): Because of (1), you have been placed on a fixed rate of 1088 (download). After resolving (1), this may resolve itself, otherwise, complain to Sky, but until (1) is fixed there's no point in complaining.
I'm starting to talk myself out of this now. Since I swapped out the Sky router, the noise margin graph on Routerstats has been rock steady, I'm starting to suspect Sky's router may have been the cause. That said, we never had problems every night so I suppose it could be that whatever was causing intereference just hasn't been used for a bit. I guess there's no choice but to wait and see on this front.
Sorry, I know you're probably all sick of me by now, but I'd really like to find out what's going on here :)
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Even if your margin has stabilised at 11-ish dB, a speed of 1088 with that margin isn't exactly stunning for a 55dB attenuation, especially with your filtered faceplate. No two lines are alike and yours may just be unlucky ine, but with similar attn to yours, mine would usually connect at something well in excess 2500 with a 12dB margin.
If there is a problem, and if it has become a reasonable stable and persistent problem, it may at least be easier to track down. Have you tried waving an AM radio around too see if it picks up anything and, if so, whether you can use it to trace the source?
If you do use the AM radio, just be aware that much interference is essentially mains-borne, and holding the radio close to any mains wiring can make it louder, which can be misleading. I recently adopted a tactic of tuning in the radio, leaving it on one place, and then switching off each circuit in turn at the consumer unit until it stopped. It turned out I've an electrically noisy SMPU in the ceiling that powers some halogen lights in the kitchen, and it's costing me a couple of dB margin. A couple of dB wasn't enough incentive to tear down a ceiling to fix it, but at least that particular mystery was solved.
BTW rechecking my own contribution from (late!) last night, I didn't mean to contradict coolsnakesman, it may well be a good idea to ask Sky for help. I only meant that there may be no point complaining about the fixed-rate until the problem's resolved.
- 7LM
edit: changed 'most interference' to 'much interference', as it probably often isn't.
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Every little helps thats the way i see it so no offense has been taken:). Sky could very well re-configure the line for you and increase the speed but if there is a problem there with interference then that configuration will be short lived. Maybe the AM radio would be a good idea but at the same time you could get an SFI sent out to identify REIN and then you will be tasked a REIN engineer to do the job for you if you want to go the lazy way around it lol. I guess if it was me i would go into the test port then contact sky after a couple of days to advise what is happening and let them do the leg work after all that is what they are there for. You mentioned you changed the router did you flash your originally router from sky to get the username and password cause if you did don't mention this at all as you won't be helped due to be in breach of T&C so keep that hush hush if your talking to there tech support. Good luck with this i am sure you will come to a conclusion soon enough but remember these type of issues are by far the worse and also the longest to take to resolve.
Regards
Gary
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Thanks both, dug out an old portable radio last night but didn't get round to a full check of the neighbourhood (presumably this interference could be anywhere between my house and the exchange?)
Mostly I just got radio 4 :D
@Gary I didn't "flash" the old router in the sense of messing with the firmware, I think it was a html thing off Sky User website that pulled out the details. Regardless, I'll keep quiet about that since, as you say, Sky don't like it.
Will try to have a walkabout and post my findings (if any) in a couple of days.
Cheers
Wildy
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this interference could be anywhere between my house and the exchange?)
In principle that's true, so certainly keep an open mind.
But (others may disagree here... I'm by no means the forum's REIN expert ) I'd argue it's more likely be to be closer to your home, and possibly even within it. The router will be more vulnerable to interference that is generated nearby , simply because the interference signal decays with distance. It's also possible that the interference is being injected into your phone line remotely and overwhelming the DSL signal before it reaches your home, but that would also be more likely closer to your home than the exchange, since it's easier to overwhelm a DSL signal that's already attenuated, rather than a nice strong signal where it leaves the exchange.
Routerstats should be able to draw 'bit-loading' graphs, which can be useful. If you see an obvious dip in the graph, it can give you a clue what frequency to tune on the radio, though in many cases it may just be general noise over many frequencies. See link for a calculator that converts dsl tone numbers numbers to frequency... http://www.kitz.co.uk/adsl/adsl_technology.htm
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Have had a look through the bumf about bitloading, and found the facility in RS (pic attached). Would I be right in thinking I'm having real problems with tones 113 - 130?
As an aside, we got a letter from Sky today saying they're winding up the Everyday package and we're being upgraded to the ADSL2 unlimited package. I daren't even guess what will happen to our connection then.
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Hi Wildy,
With the exception of the pilot tone 64 you have noise problems wherever there are no blue "pencils" or short ones too.
ADSL2 should give you slightly better performance but more if your noise problems were cured.
Kind regards,
Walter
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Hi
@wildy: RS provides the option to display bits and tone /SNR margin . See button next to SNR button . The advantage you can see the actual Margin /tone ,rather than having to calculate it from the bit loading and SNR.
Regards Jeff
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Have had a look through the bumf about bitloading, and found the facility in RS (pic attached). Would I be right in thinking I'm having real problems with tones 113 - 130?
IMHO, in addition to the Jeff an Walter's comments, it certainly looks a bit suspect and it'd be well worth tuning your radio into that area, around 500-550 kHz. If there's a powerful AM transmitter then that would explain the big gap, but if you mainly hear buzzes and crackles then you'd probably be onto something.
Radio 5 live does cause problems in many parts of the country, at the lower frequency end (upper wavelength) of the old MW band. But I'm not sure if these are the frequencies typically used. I hope not.
I do get a gap for radio 5 myself, but it's not as pronounced, or as clean-cut, as the gap you've posted. Sorry I can't show you, my router died a few weeks ago and I'm using a temporary one, and haven't bothered setting it up for RS.
I don't suppose there's a huge BBC Radio tower overshadowing the end of your garden ? :o
- 7LM
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Just reposting bitloading graph changed as per Jeff's comment. I've got no idea what this one means I'm afraid :-[
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I don't suppose there's a huge BBC Radio tower overshadowing the end of your garden ? :o
Nowt round here but speed bumps, do they work on adsl signals?
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[Nowt round here but speed bumps, do they work on adsl signals?
:lol: Nice idea, but don't say it too loud or you might find some of the Indian ISP support centres take it seriously and add the topic to their scripts. :D
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Hi
List of mw radio stations (http://www.mediumwaveradio.com/uk.php) in UK
Something very odd about your Bits tone /snr margin graph. Even where the SNR margin is very high the bit loading does not appear to be optimised .As an example around tone 133 where there is no bits allocated the snr margin is 17,18,19, 17 db ??
Never seen such a spiky snr margin tone .
Regards Jeff
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List of mw radio stations (http://www.mediumwaveradio.com/uk.php) in UK
@Jeff That's a useful link Jeff. It does seem to indicate there's no high power transmitters around 500 to 550, which renders radio interference an unlikely explanation, unless Wildy happens to live next door to one of the few low-power transmitters. Correct me if I'm wrong, but wouldn't the high margin on these tones just be consistent with the fact that they had been unavailable in the past, and the router hadn't got around to swapping them back - or for that matter, the router hadn't bothered to swap them back as it had nothing to gain, since it could easily maintain its connection speed without swapping? What do you think, Jeff?
@Wildy, in addition to Jeff's comments, do you hear any marked buzzes/crackles on the radio - perhaps intermittent - in the region I mentioned...? It's probably near the end of the dial (lower freq/upper wavelength) on the MW band?
BTW, RS is clearly incredibly useful but it's not very responsive in real-time. If you think there's an intermittent problem, I personally find the native Netgear HTML interface is often better as it reports the SNRM with a refresh rate that's configurable right down to 1 second. If you have access to something like a small laptop, or better still an Ipod Touch or the likes, you can either listen to a radio, and/or wander around the house switching things on/off, and see an almost instant change in SNRM when the problem strikes.
- 7LM
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@ 7LM,
The reason that I'd mentioned faulty ADSL equipment in the other noise-related thread was that I know BT O stipulate power output to reduce cross-talk, although I believe a larger problem exists when VDSL is deployed in the same cable. However that doesn't preclude any high-power capable device from causing difficulties in the same bundle.
A year or so back I came across a faulty analogue wireless phone which played mayhem with ADSL2+ signals whenever a call was made. The offending device was replaced with a modern DECT phone and everything returned to peaceful normality.
Kind regards,
Walter
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The reason that I'd mentioned faulty ADSL equipment in the other noise-related thread was that I know BT O stipulate power output to reduce cross-talk, although I believe a larger problem exists when VDSL is deployed in the same cable. However that doesn't preclude any high-power capable device from causing difficulties in the same bundle.
Agreed, anything's possible. That train of thought is particulary relevant as Wildy earlier mentioned that others in the street have similar connection speeds.
A year or so back I came across a faulty analogue wireless phone which played mayhem with ADSL2+ signals whenever a call was made. The offending device was replaced with a modern DECT phone and everything returned to peaceful normality.
I'm not surprised by that, the old analogue cordless base stations used to TX just off bottom of the MW radio band, about 1.6MHz I think. That's not so far from ADSL frequencies, and well within ADSL2+ frequencies. I think opinions still vary as to whether DECT ever spells trouble for ADSL but, personally, I'd take it as a forgone conclusion for old analogue cordless.
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unless Wildy happens to live next door to one of the few low-power transmitters.
Nope, only one on that map within about 50 miles of us is the Virgin 1242 one, I guess I can stop looking for cunningly painted masts now.
Will try and supply better answers/comments later, as I'm supposed to be working at the moment :)
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Is your phone line overhead or underground? There is alot of spikes going on there from what i am reading on that graph but excuse me for my lack of experience on those graphs i haven't really used them before so please do correct me if i am wrong. If you have overhead cabling and live somewhat out in the sticks there is still that possible chance of perhaps a tree branch knocking of your cable which wouldn't be caused by powerful winds just the slightest of wind can cause the branch to move and scratch of the cable this can cause noise spikes causing your BB connection to do these type of things i have seen this as a problem in the past for BB users that live out in the sticks. Off course underground cabling wouldn't be getting effected by such a thing however if it is underground do you live near a busy/main road or dual carriageway as the likes of lorries and cars and basically any vehicle type going over the road can cause vibrations which can also cause these spikes. There is a way OR can fix that sort of thing to reduce the amount of vibration going through the cables they will just put that down as an underground cabling fault. Try not to just look at REIN but look at the bigger picture cause there is other types of interference out there. If this is something beyond your premises then leave this to your SP to contact BTW to deal with this as long as you have eliminated your own domain and find no faults there then your job is done the rest is down to who you pay for the service cause at the end of the day thats what your paying for:)
Regards
Gary
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To the best of my knowledge the cables are underground the whole way here from the exchange, so I think tree-spotting is out for now. We're on the edge of town, though the exchange here also serves the next town over, a couple of miles down the road, and if BT's availability checker is to be believed can supply them with the same speeds as we're getting. It appears to be raining now but I'm off work tomorrow so will try and get busy with the radio and see if that sheds any light.
I'm also no expert on the bitloading malarky but I'll try restarting the router during quiet time tomorrow and see if that gets any improvement.
If nothing comes of that it looks like another call to India's on the cards. Thank God the calls are free ;)
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if BT's availability checker is to be believed
It's not. It gives the impression of being based on something scientific but in reality, in many instances, it seems to simply adjust itself to show the actual speed achieved by each line over a long-term average. For example, mine currently shows 4Mbps, whereas my closest neighbour shows 1Mbps, yet both are fed from the same manhole just outside my kitchen door. Before I sorted out my wiring, mine also used to vary from 1 to about 1.5 Mbps. My neighbour's internal wiring is very badly broken, with some extensions that don't work at all, which explains his results. One of these days, he'll let me fix it for him :)
If you know your neighbours' phone numbers, the BT checker is actually a useful way to snoop on their connection (long term average) speeds.
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hi
@7LM quote Correct me if I'm wrong, but wouldn't the high margin on these tones just be consistent with the fact that they had been unavailable in the past, and the router hadn't got around to swapping them back - or for that matter, the router hadn't bothered to swap them back as it had nothing to gain, since it could easily maintain its connection speed without swapping? What do you think, Jeff?
Bit swap will only operate on the tones that were recognised as available during the synchronisation process ,when the bit allocation table is created .So it is possible that those tones were not allocated any data bits at that time because the SNR was too small to enable the minimum 2 data bits (6db) + the target SNR . This then suggests that there is some big changes in SNR (noise) .
If we look at the graph we can see that there quite a few channels that could have at least 2 data bits or more available/added if the target was the normal 6db .
@ Wildy: quote I believe, also had the same problems when going straight through the test socket behind the faceplate.
Believe ? Have you confirmed THIS ? (1)
Have you tried to improve your connection (http://www.kitz.co.uk/adsl/socket.htm) ? (2)
Until Your target snr margin drops ,which is dependant on the line quality it seems you may be stuck with this connection speed . to have a chance of this happening : 1,2 above are relevant .
Regards Jeff
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@Jeff,
It might be a mistake to be thinking in terms of target margins, here.
It seems Sky have their own version of DLM and, whereas BT's DLM normally makes it's adjustments via target margin, Sky's operates - sometimes at least - by imposing fixed line rates. Since it seems that Wildy always connects at exactly the same rate (1088 DS), it seems fair to assume that Sky's DLM has put him on such a fixed rate. See also posts earlier in the thread, from coolsnakesman and kitz.
- 7LM
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@Jeff Sorry, looking back it wasn't very clear but at that point I was thinking about the disconnections/resyncs which I'd also been suffering (but which seem to have cleared up after replacing the Sky router with a different one). Everything else is the same through the test socket. Bitloading graphs attached, first one after a restart this morning, second through the test socket just for completeness.
Edit: I have the attention span of a goldfish
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Hmm, possible schoolboy error here, took another look at the wires following Jeff's comments, seems the 2 wires I took to be 1 orange/white and 1 white/orange are in fact both white/orange and the 2 orange/white ones are still connected. Can/should I pull these out?
:-[
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Hi Wildy,
Never mind the colours; you need to have wires for every extension cable ONLY in pins 2 & 5 as shown here:-
http://www.kitz.co.uk/adsl/socket.htm
Kind regards,
Walter
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Hi
quote from Wildy To fully answer Jeff's question, I'm on sky's medium package (up to 8 meg, some download limit I don't think we've ever come near to hitting)
Have you confirmed this with your ISP?
Regards Jeff
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Yeah agree with jeff check with sky to make sure you have not gone over your download limit cause i do know before i left sky broadband as a level 2 agent they where starting to crack down on there LLU customers who where taking the pee basically and starting to cap them.
Regards
Gary
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Perhaps Jeff is a little bit psychic, but looking yesterday Sky have decided (as of May 1st) we have in fact gone over the limit twice in the last 6 months but rather than cap us they've 'upgraded' us to the Unlimited package.
Bloody cheeky seen as we've had neither of the 2 emails we're supposed to get before this happens >:(
So we're now on "up to 20meg". This morning we were syncing at 760k, after a morning wasted on the phone to various Sky people we now have a whopping 1155k.
I hope we're still in some kind of training phase as this is just pathetic to be honest.
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@ Wildy,
I wouldn't raise your hopes too much. I suspect that any training would be unlikely to increase you speed to any great extent.
Sadly I suspect you'll need more patience and even more phone calls.
Kind regards,
Walter
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Stick it out with a level 1 agent on the phone. All you really need to do is tell the level 1 agent you are in the test socket with a new router and filter and to get you passed to CST. Your line should not be syncing in at this speed there is something wrong with it and your 10 days has past for DLM. Your line may go back onto DLM because of the regrade however this does not make an ounce of difference cause your still not syncing higher on ADSL2+! Not to mention you are started on 4096Kbps downstream and 512Kbps upstream on the unlimited package then it determines your speed after the 10 days. Your not even getting that! Get on the phone to sky and get them to fix it.
Regards
Gary
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Another day, another call to Sky. Today our connection had dropped back below what we were getting prior to the 'upgrade'. Called up today, they have at least given me a reference number which seems to be an express ticket to talking to CST. They've managed to bump it up to 1.3 meg** now (by putting us back on g.dmt by the looks of it, and they're going to call back tomorrow to see how it's going.
A few questions in the meantime if I may:
1) They keep quoting a distance of 4.7km and max speed of 1.5M, this doesn't tally with either the attenuation quoted by 2 routers or the opinion of a BT engineer I asked (They both come to about 3.7km) so where are they getting this from? I get the impression they see this and decide immediately there's not much they can do.
2) Power figure on routerstats is all over the place, varying anywhere between 0 and 26db. User cock-up (not unlikely I must admit) or something happening with my connection.
3) Bitloading graph attached - should the margin at higher tones vanish like that? it was there in the earlier (when we were on ADSL1) graphs
Thanks again for your time all, much appreciated
Wildy
**Edit: while typing this the router DC'd and resynced at ~800k
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Hi again Wildy, I've been keeping quiet this past few days, but hope you don't mind if I chip in again...
While trying to sort what seems to be a REIN issue with my connection, I have come across something else which is puzzling me. At good times I can have a noise margin of 10-11 db, (I guess from that the target is 12), and a sync speed of 1088kbps. Then when the noise problems kick in on a night, noise margin plunges down to 2 or 3 db, frequently causing disconnections too, but after these it still always resyncs at 1088 kbps.
That quote is from your opening post on this thread.
The fact that your margin sometimes drops that low, at a speed of 1088, suggests you're unlikely to sustain a connection speed much greater than that, no matter what package they put you on.
In contrast, your attenuation of 55dB suggests (doesn't guarantee) that something like 3 Mbit or more (maybe even 4 to 5) ought to be within your reach, but only if you (or Sky) can identify a physical wiring fault, or a source of REIN, that explains your current predicament, and rectify it. Meanwhile, switching between different packages seem a bit pointless to me.
Personally, I'd focus on looking for REIN issues, or try to force SKY to do so, and avoid any 'upgrades' until that's been done.
Don't worry too much about actual distance from the exchange. The parameter that primarily dictates the line's potential speed is it's attenuation, and that is freely available for all see, 55dB from your initial post. 55dB would usually equate to about 4km, though it can vary (for example, aluminium wire would attenuate 55dB in a shorter distance). The point is that it's the '55dB' that matters most, not the '4km'.
- 7LM
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hope you don't mind if I chip in again...
Of course not, that's why I keep posting this rubbish up here :)
The upgrade wasn't at our request, Sky decided we'd gone over our d/l limit twice in 6 months and 'upgraded' us automatically, despite failing to send either of the 2 emails that are supposed to come warning that this is coming.
I'm entirely with you that there's a fault that should be sorted before anything else, but this 'upgrade' being foisted on us has well and truly muddied the waters, I'm afraid ???
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Fair enough, it sound like you're doing the best you can. Just stick with it.
As I said in another post today, if ISPs don't like what you're asking for, they often seem to pretend you've requested something different, and respond to that imaginary request instead. :)
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Hey wildy. Yeah that is a ticket id for CST be sure to keep that safe and don't loose it. I could of helped you a bit more if CST had of still been in belfast but they shifted it back out again a couple of days ago so you will be dealing with shepton. The estimated line distance is wrong they got mine wrong when i was with them saying i was 1.7Km when in actually fact i am 3.8Km! Stick with the results you have got. Keep pushing them for an SFI engineer and be sure to tell them EVERYTHING you have done and don't miss one bit of detail cause that small bit of detail can throw them off making them think of a different scenario. Good luck and keep us posted.
Regards
Gary
P.S I have actually got a contact in shepton i could kindly ask to check your ticket id for you and see what he can do.
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Just had my call-back from Sky, since a restart this morning the line has been ok (at least by Sky's standards, they don't want to accept this line can go faster than 1.5 meg). I mentioned that last night had been much worse, with disconnects and slow speeds, and after looking at it the guy said there was some build up of errors on the line.
So I am now awaiting a new Sky router, not sure that this will help anything but at least if the problem persists it's another thing ruled out and another step closer to getting sorted.
@Gary Thanks for the kind offer but I reckon there's not much else to do but wait for now :)
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They should beable to see from your SNRM thats your line should beable to acheive faster as it is high enough for more room but sometimes those guys don't think of it that way they look at a high attenuation and automatically think "slow speed" lol. Have you not already tried with another router? You can plug a 3rd party router in just to see if it syncs any higher but it won't log in sky don't mind you doing that as long as your not flashing the router to obtain the username and password. You should get back onto the phone to them and tell them you have already connected a 3rd party router and found it is still not syncing any higher and demonstrate it to them over the phone by plugging 1 router in at a time so they can see for themselves that replacing your router was a waste of time.
Regards
Gary
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Yeah they already know I've used a 2nd router, but because it's from before we had Sky, they reckon it's old and want me to try with a new one.
Just to add a bit more confusion to the story, Dad had asked my uncle who works for BT if he could find the line length for our house. I know this is a bit vague because I got the info second hand but he came back with a line length of 5.7km. I suppose that's possible if they went through the next town over then back to us, but then I can't understand how we've got such low attenuation. Is there any way of finding out for sure the actual route of my phone line?
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Wildy,
Correct me if I'm wrong but, judging from recent posts, your connection speed is no longer fixed, it seems to vary with each reconnect? That would indicate you are back on an adaptive rate.
I assume Sky's DLM will still use a 'target margin' feature similar to BT's DLM, in which case it would be nice to know what your target margin is set to. The interesting parameters would be the connection speed, and the SNRM, immediately after a reconnect.
As for line length & attenuation, different routers will report different figures for attenuation, it's only approximate, and that's normal. However, there usually within a couple of dB difference one to another, and not nearly enough to explain a 5.7km line being reported as 55dB. A 5.7km line would normally equate to nearly 80dB and you'd be lucky to get any DSL at all. It'll be interesting to see if the new router also reports 55dB but, if it does, I'd just disregard that 5.7km figure.
- 7LM
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OK, restarted this morning, can't remember the exact sync rate but it was low 1200's noise margin 9db.
Tonight has been a bad one but at least proves I'm not on a fixed rate anymore (I think), as you can see from the attached graphs the noise knocked me off a couple of times but resynced at a lower rate each time. Made a right mess of my bitloading graph too :(
[attachment deleted by admin]
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Hi Wildy,
Yes - it proves you're not on a fixed rate.
What also worries me is that the line is connecting circa 1200 with a 9dB margin. With a 6dB margin instead of 9, you would only gain maybe another 400-800 kbps, so that may the basis of Sky's argument for saying that your line's only good for 1500. They're being slightly pessimistic, but not hugely so.
That leaves the interesting question of why your line, with 55dB attenuation, behaves so much more less good than most similar lines. I think you already said the test socket didn't improve things, which seems to suggest three possibilities (1) the router knackered, or (2) an external wiring fault, or (3) very strong interference.
I know that only repeats what's been said already and doesn't maybe help you a lot. I guess the next step is to try that new router, you never know - there's an outside chance it'll improve things massively, but don't pin you hopes on that. Otherwise, it'll at least confirm (or not) that the attenuation is 55dB-ish, which would give you more ammo' to plead with Sky to look at it more closely.
I don't know if anybody else may have comments on the latest routerstats graphs... it's interesting the way there seems to a a progressive SNRM decay after each rescyn?
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Just so you know sky have 3 target SNRM's. They are as follows: 7db, 9db and 12db. However they are able to use another system for lower SNRM targets such as 3db but its very rare they do this. If the new router doesn't make an such improvements then you are entitled to request an engineer to come out. Your 55db attenuation means your line must be pretty good for the length of line you have as this figure is measured with quality and distance and i am sure a few other things that i don't know about lol. Best of luck with that and i hope those details help the rest of you guys.
Regards
Gary
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Hi
quote sky have 3 target SNRM's. They are as follows: 7db, 9db and 12db.
Looking at the SNR margin it looks as after each disconnection the Target has gone up so each time the synch rate has paid the penalty .
Starting with target 7db , best it achieved ~8db synched ~920Kbps
then noise on the line increased to a point where it lost synch
resynch with 9db target so synch rate now 700 Kbps noise still getting worse until synch lost even with higher Target .
resynch with 12db target with ever increasing noise synch rate now 300 Kbps . Even with a target SNRM ~4 times higher the noise is still getting worse and the noise spikes cover about 4db that is +-2db around the mean.
this noise source has 2 characteristics
1 is that the general noise over about an hour is increasing quite rapidly.
2 the noise source is very spiky and seems to be much worse as time goes on . Normally you would expect the spikes to be smaller with the higher target SNR margin ,remembering that the actual target SNR scale is logarithmic .
There must be some very strong spiky interference(REIN) .
Regards Jeff
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Hi all, me again.
New router made no difference (as expected). Called back and BTO blokey is coming out Tuesday morning. Will let you know how it goes after that.
(Unless I've done something stupid and got charged 140 quid, I'll say nothing then ;D)
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:fingers:
I've heard it said that jaffa cakes and tea are a good investment when BT come to call. Some folks have even gone as far as a bacon sandwich. :)
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Tea and biscuits should be doable, bacon sarnie reserved for if it gets fixed.
If he turns up at 8am as threatened all he's gonna get is an annoyed-looking fat man in a dressing gown.
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lolll that doesn't sound nice to look at lol. You won't be charged for the engineer visit sky will cover the charge for you unless they decide to redirect the charge to you which they won't. BB engineers are usually free of charge. What happens is BTW will charge sky for the engineer if it turns out to be a fault in your domain and not on BTW's network and if sky feel its fair for you to be charged they will then redirect the charge to you. I work for sky BB tech support for 3 and a half years they don't redirect any of there charges they cover them all even if your router turns out to be faulty or ur filter sky still cover the charge so don't worry about it:)
Regards
Gary
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This may be a silly question but are there 'proper' broadband engineers or are they all just BTO guys who do whatever jobs they're given?
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Hi Wildy,
My experience with many poor to horrible lines around Ewhurst is that, like any organisation, BT do have specialists and they can escalate a fault.
However there are quite a few, even some engineers that I observe as being very helpful, who are not aware of the intricacies of what can be a difficult subject.
There is also an inbuilt constrictive mechanism which I believe is designed to reduce BT's activities to the minimum.
The major hurdle with a difficult fault is to get beyond the first line and to be able to define a specific fault that BT feel they are obliged to fix.
It's much better if the fault can be classed as a telephone fault rather than a broadband one.
The worst situation is to force BT into declaring a line as a "false green" so that, without the Universal Service Obligation, BT can just leave you to rot.
Thankfully those occasions are rare and should drop even more with FTTC solutions installed.
At the first level BT Engineers sometimes seem to be strongly discouraged from attempting to investigate matters in detail. It must be very frustrating for the keen ones knowing they have to leave a fault and, unless they are lucky, will have the fault re-investigated by someone else without knowing in detail what has been attempted. The engineers do usually fill in a job sheet with details of their findings, but it depends upon their thoroughness whether this is sufficient.
That said, there must be many faults which are simple to cure and are successfully dealt with quite efficiently.
On the other hand I have had some which go on for over 6 months as they are intermittent and BT's system just can't cope with them.
In those situations it is vital to have an ISP who will go the extra mile and can take note of Routerstats and the other long-term diagnostics we have available here.
BT can log some data but, in normal circumstances, it falls far short of our capabilities here. The trick is to harness all these resources in the most efficient manner.
BT do not like publishing their network difficulties so knowing what performance is achieved locally can be a great help; as can a knowledge of the states of the lines especially aluminum ones which can be a nightmare.
Please note these are the observations of a local helper not linked in any way to BT. Perhaps some ISPs and / or anonymous BT staff might like to add their comments?
Kind regards,
Walter
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There are several different types of engineers within OR that qualify for certain types of jobs. The type of engineer you are having sent out is an SFI engineer (special faults investigater) who can do pretty much everything for example lift and shifts, request for line cards to be reset and can also deal with the local network if there is any underground cabling faults or any faults at the DP or MDF or the PCP or SCP. They can also identify REIN issues but that requires a REIN engineer to find the source using a wee special tool and this can take a while to identify. There is also frames engineers who only deal with the likes of jumpering (cabling at the MDF) and also they can identify faulty equipment so they can take your BB equipment out of the MDF if this is causing an issue with your PSTN. Then you have transmission engineers these guys deal with certain aspects of the equipment also at the MDF so if your issue is something along the lines of noise on your line when the router is connected thats when a transmissions engineer will be sent to the exchange to check the likes of the splitter (big microfilter) at the exchange which seperates the phone service from the broadband service. The SFI being sent out to you will beable to identify any of these issues on the local network, exchange equipment and your own domain by fault finding. Don't be afraid to ask the engineer to explain what he is doing and ask what his findings are aswell. Make sure he demonstrates to you and explains to you in simple terms you can understand what he believes he has found and how he has fixed the issue.
Regards
Gary
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BT guy has been out tinkering today. He started off doing some tests on a laptop through the phone socket, then disappeared for a couple of hours. When he came back he said there were 3 lines up to where we live and we were on the poorest one. He's now swapped us over to the better one.
Stats tonight as follows:
Noise Margin: 8.6 dB
Connection Rate: 2016 Kbps
Line Attenuation: 47.0 dB
Power: 17.6 dBm
Max Rate: 2336 Kbps
SF: 14275
SF Errors: 21
Reed Solomon: 485382
RS Corrected: 258846
RS Un-Corrected: 486
HEC: 14
Errored Seconds: 3
Severe ES: 0
Interleave Depth: 64
Bitswaps: 0
It's certainly an improvement (pretty much a 100% speed increase) but I still think we should be doing better :(
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@Wildy,
Did you ever get Sky or BT to take any more interest?
I see your attenuation now shows 47dB, whereas it used to be 55dB, is that correct and consistent? I guess it's theoretically possible that your new line could take a much more direct route to the exchange, but it doesn't seem likely. Normally, line attenuation shouldn't change much, except that different routers can report different figures (a couple of dB or so either way). Large changes in attenuation can suggest an intermittent line fault, so it's possible your old line had a fault, and your new one doesn't, which would explain you speed gain.
Regardless of why the attenuation has improved, I still think you're right, 2016 is disappointing even for a 55dB (as it used to be) line. For a 47dB line it's downright pathetic - the kitz calculator predicts over 5500. The 8.6dB noise margin is high, but nowhere near enough to explain that discrepancy.
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Hi again.
I'd left it after Tuesday as there was a marked improvement in speed, a stable 2 meg connection would be ok for us and I wanted to see how it went. Unfortunately we've had the same noise issues and disconnections as before, guess I'll be ringing them back again tomorrow to look for more help.
I know I'm massively unobservant, but Dad has just pointed out there's a (very) small electricity substation close to the cabinet that serves the houses here. Could that be a likely culprit? and if so, is there likely nothing that can be done about it?
Cheers once more
Wildy
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@Wildy,
Whilst any electrical device can cause problems, substations are usually quiet. If they're not you should probably hear some strange audible noises and if so I suggest you call the number on the identification plate. As they are heavy current devices you might expect things to get hot and possibly start smoking or at least smelling hot, if there is a fault.
I suggest you run Routerstats Lite and record your findings for us to look at.
http://www.kitz.co.uk/routers/log_routerstats.htm
Kind regards,
Walter
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Thanks Walter, have added some pages from RS this afternoon, looks like a pretty typical example of what goes on. I'm not sure if there's anything else I should be watching other than moise margin and sync speed. Have included the stats page as there seem to be a lot of errors (hopefully someone can suggest if those are excessive or normal).
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[attachment deleted by admin]
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Hi again Wildy,
The noise margin graphs do look quite horrible. There's little doubt that you are suffering from some form of noise injection, but quite different characteristics before and after the second probable re-sync.
You'll see at
http://www.kitz.co.uk/adsl/max_speed_calc.php
that you are under half the sync speed you should be achieving probably because of the state of the line.
Have you removed all ring wires and connected the modem to the master socket ?
Have you tried wandering around with a de-tuned AM radio ?
Is there any heavy plant near you, or perhaps old refrigerators or air-conditioning units etc. etc.
Kind regards,
Walter