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Sync speed & Noise margin
This is a discussion on Sync speed & Noise margin within the Sky Broadband help forums, part of the Sky Broadband help and support category; So it's normal to have to disconnect or reboot the router then? EVERY DAY! surely it should be set up ...
- 20-09-06, 08:34 PM #111
So it's normal to have to disconnect or reboot the router then? EVERY DAY! surely it should be set up to automatically re-sync when the connection gets crappy? I've had to reboot twice tonight already..
- 20-09-06, 08:36 PM #112
I haven't got a filtered faceplate. I would like to order one but I can't find any made by BT - where did you find yours from?
The microfilter that I am using is including in the Sky Broadband package. I only need one of them (3 included).
I've also had to reboot twice due to no connection.
- 20-09-06, 08:49 PM #113
Since reporting such bad noise margins I have had a steady connection for 40 hours (a new record!) and a more or less constant noise margin of 19db, even at 6-7 a.m when I was getting a low one. I've done nothing whatsoever to achieve this so I've no idea why it's improved so much; maybe there was a problem at the exchange that's now been fixed.
As you say, Tadunne, you should not have to reboot the router to reconnect - it never happened on my previous DG834 (not T) and ADSL MAX connection - it would always automatically reconnect. It's a real pain that you seem to have to take manual action to get it online again.
- 21-09-06, 01:05 PM #114
If I still have to keep rebooting my router I wonder if there is any timer device I could buy to switch the router off and back on again so I don't have to keep messing around lol
- 21-09-06, 01:41 PM #115
What I find irritating is that there are two issues going on, neither of which show signs of resolution.
1. The ADSL2 protocol supports re-training when the SNR drops below a threshold, with the aim of keeping the SNR high (and vice versa to get the speed back again). Clearly, this isn't working.
2. Why does the SNR plummet anyway for most users around late afternoon / early evening. Some small SNR is acceptable, but not the 7 to 0.1s that some are getting. Again, this shouldn't happen and there is no indication of a resolution.
Not good.IQ album "Dark Matter" artwork reproduced with permission. See www.gep.co.uk/iq for more information.
- 21-09-06, 05:35 PM #116
Two good questions - neither of which have I seen any answer to.
Re. the retraining, presumably this is firmware related or it it somehow triggered at the exchange level (unlikely I'd have thought)? Does vanilla Netgear firmware support this - maybe someone who has reflashed their router can say. If so then that's another black mark for Sky's *******ised version.
Re. the noise margin plummeting in the evening, I'm now thinking that this might be a complex problem. When I first got SkyBB I synced at a bit above 9000kbps with a margin of about 7.5 (attenuation of 40.5). However by late evening the noise margin would plummet down to about 2.5 and when rebooted the router would resync at about 6800kbps with noise margin a little over 7.0.
Having an old mastersocket and not liking the microfilter dongles I got a friendly BT engineer in to fit a new filtered faceplate and clean up the connections a bit. I was chuffed to say the least that when I reconnected the router resynced at 14500kbps (again at about 7.0 noise margin but with an improved attenuation of 38.5). However, what I found really surprising and don't have an answer for is that the normal evening plummet has been replaced by a more manageable dip of 2.0 in the noise margin (which I understand is perfectly normal).
Unless the reduction in severity is just a coincidence then it seems to me that the problem may lie in the router firmware not dealing with a noisy line very well and this being compounded by something at exchange level which exaggerates the required noise margin? Isn't it supposed to block out and adapt to certain frequencies? If it's blocking but not adapting would this give this problem?
Last edited by Saturday; 21-09-06 at 05:37 PM.
- 21-09-06, 08:22 PM #117
While I was on the phone about switching interleaving off (which they did!) the tier 3 support guy also tinkered with my connection:
ADSL Link Downstream Upstream
Connection Speed 6719 kbps 983 kbps
Line Attenuation 43.0 db 26.2 db
Noise Margin 4.3 db 6.5 db
DSL Link Downstream Upstream
Connection Speed 6182 kbps 764 kbps
Line Attenuation 43.0 db 26.2 db
Noise Margin 9.1 db 12.5 db
I seem to have gained a bigger upload, not sure what he did about the downstream. I have ordered a ADSL Nation faceplate so I will see how it goes.
Is it worth asking BT if they can do anything about my high line attuenation? Or would they just turn on interleaving and thus ruining my much waited for feature to disabled!!
- 21-09-06, 09:10 PM #118
That's interesting - my router would drop its connection with a noise margin that low.
No not much BT could do about your attenuation. This is largely a measure of the length of your line. I found a filtered faceplate and a clean up of the connections made a small difference (from 40 down to 38.5). However my connection speed increased enormously!
- 21-09-06, 09:15 PM #119
My downstream SNR is only 5.6 db atm. I think he set it too low (he called it 7,7,0,0) or something, but I had a hard time getting him to explain.
The extra upload is welcome, as is the lack of interleaving. I've just rebooted it now as my connection was just dying (it seems to happen at night 3 times!). Its so annoying.
What exactly did you clean and what with?
Update: it seems to go as low as 1.8 db. The only way I can think of how he increased the downstream is by lowering the SNR margin. But it's already 6 db before he did it. I am getting ping requests timing out, and slow browsing speeds.
Last edited by LuckyKnight; 21-09-06 at 09:23 PM.
- 21-09-06, 09:48 PM #120
is interleaving turned on by default? how did you get through to tier 3? I've tried a few times at the moment I'm waiting for BT to test my line for them. I've never actually spoke to a tier 3 person tho? I think all my connection needs is some tweaking..