adsl2 from max Is 9.5dB downstream attenuation increase ok

Hi, a little advise please, i was with plusnet for 6 years on adsl max getting around 8000 sync with a down attenuation of 19dB, last few weeks lots of drops and sync down to 6000, I have now moved to sky llu unlimited and the downstream attenuation has increased to 28.5dB
i am in the 10 day line training second day.stats below. i fear that with the increase in attenuation and reduced noise margin it will not get much better.

Port Status TxPkts RxPkts Collision Pkts Tx b/s Rx b/s Up Time
WAN MER 80988 99746 0 0 0 05:48:02
LAN Down 0 0 0 0 0 00:00:00
WLAN Up 3096588 2049470 0 0 4032 37:19:41
Broadband Link Downstream Upstream
Connection Speed 7002 kbps 796 kbps
Line Attenuation 28.5 dB 16.5 dB
Noise Margin 9.9 dB 15.15 dB

I can't see if that's ADSL2 or 2+ or what ?

With a sub 30 attenuation you should see over 8M sync even with a 9 dB margin

In reply to a post by frffrf:

i am in the 10 day line training second day.stats below. i fear that with the increase in attenuation and reduced noise margin it will not get much better.

Sky LLU DLM doesn't work the way other ISPs do it. Sky change the sync speed and watch the error counts. Just wait until the line testing is complete as you've only just connected.

thanks for reply phil
you said
I can't see if that's ADSL2 or 2+ or what ?

I believe its adsl2+ with MER

is a 9.5dB increase in down attenuation reasonable when migrating from adsl max to adsl2+?
I was expecting a much smaller increase
as has been stated the line training will need to complete but with such a low noise margin the increase will be small

In reply to a post by frffrf:

is a 9.5dB increase in down attenuation reasonable when migrating from adsl max to adsl2+?

No, usually about +3dB.

Can you confirm ADSL2+ or what using the TELNET interface of your Netgear?

You should get about 16 Meg on ADSL2+.

Edited by XRaySpeX (Sun 07-Apr-13 01:39:53)

hi, thanks for advise, router is new sr101 sky manufactured , no telnet available
below is the latest stats, this speed is ok for me.

WAN
MER 91926 120374 0 0 0 06:29:00

LAN
Down 0 0 0 0 0 00:00:00

WLAN
Up 3327340 2230596 0 0 4281 60:50:08


Broadband Link

Downstream

Upstream


Connection Speed
10237 kbps 1117 kbps

Line Attenuation
28.5 dB 16.6 dB

Noise Margin
6.9 dB 8.8 dB

The should be little increase in signal attenuation from changing ADSL standards, some routers report "line attenuation" rather than "signal attenuation" so it's all a bit ambiguous. 9 dB means 1/8th of the signal power so it is a significant change.

It can go up as a result of rewiring to the LLU DSLAM or because the new DSLAM and router combination interpret standards differently too.

In reply to a post by frffrf:

below is the latest stats, this speed is ok for me.

Connection Speed
10237 kbps 1117 kbps

Line Attenuation
28.5 dB 16.6 dB

Noise Margin
6.9 dB 8.8 dB

With an almost identical downstream attenuation & noise margin, i'm getting ~ 18 meg sync on a TalkTalk ADSL2+ line. There is something seriously wrong with your line. Have you tried changing your filters, connecting to the test socket etc?

Edited by deleted (Wed 10-Apr-13 13:23:07)

Sky caps speeds in a way that means no excess spare noise margin so line may be fine, just the cap Sky applies is a little low. A call to support and polite chat can usually fix it

update after line training period completed see below
Broadband Link Downstream Upstream
Connection Speed 15587 kbps 1117 kbps
Line Attenuation 28.0 dB 16.4 dB
Noise Margin 5.8 dB 8.8 dB

it backs up what others have said that sky use a different method of calculating attenuation.
i always thought it was the physical ohmic resistance of the line being measured and as it is logarithmic large increases have a marked effect on performance.
sky system seems to be able to increase sync speed and raise the noise margin, the opposite to my understanding.
thanks all for the advise