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[sevenlayermuddle]

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.

[jeffbb]

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 ? (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

[sevenlayermuddle]

@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

[Wildy]

@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

[attachment deleted by admin]

[Wildy]

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?

 

[waltergmw]

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

[jeffbb]

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

[coolsnakeman]

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

[Wildy]

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.

[waltergmw]

@ 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

[coolsnakeman]

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

[Wildy]

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

[attachment deleted by admin]

[sevenlayermuddle]

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

[Wildy]

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 

[sevenlayermuddle]

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.