once and for all... what are 'ideal' SNR and Attenuation figures?

[#1]

Yes - and a reduced speed reduces your profile almost immediately but an increased speed takes 3 days plus for it to go back up again

[#2]

Looking again your stats are a bit odd. I have a much higher attenuation than you but always sync at full speed with no disconnections. Here's my stats:
Connection Speed   8128 kbps   832 kbps
Line Attenuation 20 db 6.5 db
Noise Margin 9 db 13 db

[#3]

yes interleaved is turned on... not sure why. I'll do some daily reconnects to try and improve the IP profile
Will plusnet adjust this for me or is it BTs perogative?

[#4]

You won't do better while interleaving is on!

[#5]

Quote

yes interleaved is turned on... not sure why

It sometimes just gets turned on for no apparent reason. Raise a ticket and request it turned off, there's no reason why it should be on for a line with that little attenuation. If you're lucky James might spot this thread tomorrow and do it for you.

[#6]

Getting back to your original question about ideal figures, your ideal attenuation in dB is 13.8 dB/km times your distance from the telephone exchange measured in km as the crow flies.  It is very unlikely your telephone line takes the most direct possible route to your house so it is very unlikely you will achieve this ideal attenuation.
Your ideal SNR is 6 dB because that is as low as the BT equipment will allow it to be set.  Anything around 6 is okay but [on a long line] 9 dB would indicate that the BT equipment has concluded your line cannot sustain 6 dB, 12 dB would indicate that BT's equipment has concluded your line cannot sustain 9 dB etc.  [On a long line] Increasing the SNR goes hand-in-hand with a decrease in the maximum line sync rate. 
Edit:  Added text in [ ] .     

[#7]

Quote from: ReedRichards

9 dB would indicate that the BT equipment has concluded your line cannot sustain 6 dB

Probably not at that short distance as I said earlier.

[#8]

Quote from: ReedRichards

but 9 dB would indicate that the BT equipment has concluded your line cannot sustain 6 dB, 12 dB would indicate that BT's equipment has concluded your line cannot sustain 9 dB etc.

Not if it's already syncing at 8M on an ADSL1 line. In that case the margin could be much higher (in fact the higher the better).

[#9]

What Jelv said.

[#10]

Thanks for everyones input.
Can PN staff do anything about my IP profile their end or is the ball firmly in BTs court?

[#11]

Hi there,
I've placed the order to remove it for you, that should allow you to sync at the full 8128kb/s. I'd agree with the others in that it's most likely interleaving that's causing the difference.

[#12]

Thanks James,
My line synced at the full 8128kb this morning and has been rock solid ever since (no packets dropped or errors)
My SNR and attenuation are the same as before (i.e. fine)
However my BT IP profile is still 6500k - having been like that for 5 days now i was wondering whether there is anything anyone can say to BT to get them to increase it to the full 7150k?
Can you do anything your end?

[#13]

I don't think there is anything James can do until you've been syncing at the higher speed for at least three days without BT changing the IP Profile.

[#14]

thanks for the heads up jelv... i'll keep and eye on it for a few days

[#15]

Quote from: HPsauce

Quote from: nolluwhereilive is there anything i can do to improve my noise margin? No, and why would you? The noise margin is what it is because you are so close. The signal power is probably reduced anyway due to the very short cable. ADSL2+ would be good.

Sorry, don't agree. For that attenuation I would expect the SNRM to be higher than it is which suggests maybe undue noise on the line or an equipment problem. If you later go to ADSL2+ this will keep your speeds down.
If you haven't already, do as has been suggested, plug into the Test socket (behind the Master front plate) with no phones plugged in and any cordless switched off, and see what figures you get then. If no or very small change, try another (decent quality) filter. If still no change try another modem/router for comparison.