Re: Sky BB speed issues - improving a poor noise margin
 

Sky appear to put many people on G.DMT/Interleave, with a capped max speed, rather than ADSL2+/FastPath.

They do this if they feel that your line is too poor for ADSL2+, too noisy.

Sky's G.DMT can AFAIK go up to around 12mbps I think, while Sky's ADSL2+ currently tops out at 16mbps.




When I first connected, I only squeezed a bit over 5mbps out of it, because of my high attenuation, & my low noise margin.

After removing the ring wire, my noise margin increased, enabling me to connect at a higher speed - although it topped out at 8096kbps, as it had been capped by Sky at 8096 & was on G.DMT.


"Tier 3" is the 3rd level of Sky BB tech support...... they can, if you badger them enough, & jump through hoops with Tier 1 & Tier 2 first, switch you from speed capped G.DMT to ADSL2+.

However, if your speed sucks anyway there is little point.

Re: Sky BB speed issues - improving a poor noise margin
 

adsl2+ has many advantages over adsl1. Greater efficency is one of them. Adsl2 is Adsl2+ but with only the Adsl1 range and without the extra frequencies it can still supply speeds upto 12mbit instead of 8mbit, I think the default sky is Adsl1 matt which would be a 8mbit limit.

https://www.cableforum.co.uk/images/...2007/03/18.png

If I use my line as a example I would gain from adsl2+ over adsl1, the frequency between 794mhz and 932mhz would be used since adsl2 allows single bit tones and is less wasteful, and as you can see my useable SNR looks to carry on past beyond the 1.1mhz mark, speedwise I reckon I would gain around a mbit, which to me is good but an isp would probably think not worth bothering with and since I have a 48db attenuation I expect I would be one of those people denied adsl2+.

Adsl2+ also increases reliability and reduces crosstalk so there is really no reason other then old hardware compatability to use Adsl1 instead.

Re: Sky BB speed issues - improving a poor noise margin
 

Interesting :tu:

Re: Sky BB speed issues - improving a poor noise margin
 

Can anyone gives these stats a look over?

Re: Sky BB speed issues - improving a poor noise margin
 

Oh, for a nice error-free line with low attenuation :(



You're on ADSL2+ & FastPath, rather than G.DMT & Interleave :tu:

Your attenuation is low enough that you could potentially connect at the full 16Mbps.

But, due to the noise margin, you're actually connecting at around 13Mbps.


Have you tried the suggestions Chrysalis gave me earlier in this thread & the other Sky BB thread? i.e. try the test socket on the BT Master (behind the faceplate) to rule in/out any local wiring issues, & try disconnecting the ring wire?


From your brief bit of uptime, you've had no Error Seconds (ES) [apart from a single one going upstream], no Serious Error Seconds (SES), no Loss of Signal (LOS), & no CRC errors (CRC) :tu: [although a better test would be a few hours of up time at least, while using the connection]



You may find these handy:

http://www.skyuser.co.uk/forum/speed...explained.html

http://www.skyuser.co.uk/forum/route...ter-stats.html

Re: Sky BB speed issues - improving a poor noise margin
 

Seem to have an issue with the connection going slow till router reboot about one a day, posted on the sky user forum too. Will try the master socket later to see if that resolves it

Here are the stats from the morning after the problem believed to have occured:

Re: Sky BB speed issues - improving a poor noise margin
 

Using the test socket behind the master gives

Re: Sky BB speed issues - improving a poor noise margin
 

2nd stats...

Loads of errors! More than me, even.


3rd stats...

Seems a lot of errors, for only 8mins uptime.

Much better noise margin & synch speed using the test socket though :tu:

Have you considered removing the ringwire, getting an ADSL faceplate, improving extension wiring, etc. etc.?


http://www.skyuser.co.uk/forum/cabling-faceplate-help/

http://www.cableforum.co.uk/board/34254181-post2.html



For a proper look at your stats, I'd wait for Mossywell or Saturday at Skyuser to comment on them...they're the router gurus over there.




Noise margin varies through the day. When it gets really low, the connection can drop. However the Sky router does not always seem to realise when the connection has gone down, & so doesn't then reconnect. A reboot sorts it, as the router then reconnects at a better speed for the current noise margin. Maybe that's your problem, or part of it.

Mossywell at Skyuser has created "Bounce Sky Router", a little system tray app which monitors the internet connection & automatically reboots the router when the connections drops. You can also use it to issue custom commands, such as telling the router to resynch at a particular noise margin.

http://www.skyuser.co.uk/forum/techn...matically.html

Re: Sky BB speed issues - improving a poor noise margin
 

Another thing, shortly after reconnecting my router i got the normal noise margin then got this thing.

Rebooting restored it to normal.

Rewiring is out of the question and I don't think it will help much by the looks.

Will look at getting the ring wire out.

Re: Sky BB speed issues - improving a poor noise margin
 

There's a bug apparently which makes it report crazy noise margins sometimes.



Re-wiring is always worth it, if possible.


Removing the ring wire should at least make an improvement.


Also, even if you can't re-wire the extensions completely, it is still very easy, & definitely worthwhile, putting an ADSL faceplate on the master (depending on how your extensions are wired & used), or at least replacing the bog standard microfilters with decent ADSL Nation filters (either dangly ones, or complete replacement extension sockets with built-in filters).

Re: Sky BB speed issues - improving a poor noise margin
 

It is a brand new renovated house, I don't think rewiring something 3 months old would go down well.

Re: Sky BB speed issues - improving a poor noise margin
 

LOL, probably not.


Still cheap, quick, & easy to remove the ringwire, change the faceplate, put filtered extension sockets on in place of "normal extension socket plus cheapo dangly filter" etc.

Also easily reversible.

I rent with my fiancée. Can't go running new extensions everywhere in place of the existing "behind the walls" cables, but have at least done the ringwire, faceplate, & extension sockets. If/when we move, it won't take long to change back.

Re: Sky BB speed issues - improving a poor noise margin
 

OK. I've installed an adslnation XTE-2005. The only phone line extension is filtered at the master faceplate and the I have a short adsl extension unfiltered for the adsl modem. Removed ringwire.

So far stats are:

but the real test will come weekday nights.

Re: Sky BB speed issues - improving a poor noise margin
 

Looks like no dice. The noise margin stay relatively high but around 20:00 crc errors surge