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[MrBelter]

There is 75m of copper from me to the cab and in previous ADSL days an engineer placed a new single piece of copper from the pole top to the back of a new NTE5 when a fault occurred as it turned out the last 15 meters had more joints than a stoner on lets get stoned day.

Moving on to 2011 and getting FTTC my max attainable were after rounding up 135Mbit'ish down and 35Mbit'ish up, this of course dropped slowly as the cab filled up and over the course of time faults raised the noise margin etc to compensate and my line seemed to be living happily at 105Mbit'ish down and 32Mbit'ish up with a slightly elevated noise margin.

G.INP and ECI, or coincidently at the same time something happened and my down went up to 110Mbit'ish and my up went down to 28Mbit'ish

Moving on to now and a resync (which actually raised the up a bit) and 3 reboots which were nothing to do with me later (which kicked it in the teeth) my stats show the following:

6.   Data Rate:   19993 / 79999
7.   Maximum Data Rate:   22247 / 109593
8.   Noise Margin:   6.8 / 13.9
9.   Line Attenuation:   5.3 / 6.4

Now i am no expert but that max up data rate is getting dangerously close to knackering my actual upload speeds up and the noise margin clearly isnt right for 75M of copper with an attenuation of 5.3db.

Currently got a MKIII filter on thats been on for a month or so (i've got my MKII to put back on if anyone thinks that will help). Done a quiet line test using a BT branded (not that that matters i guess) corded phone and the line was crackle free.

[MrBelter]

I've put the MKII filter on and unsurprisingly not much in the way of change

6.   Data Rate:   19993 / 79999
7.   Maximum Data Rate:   22071 / 109955
8.   Noise Margin:   6.7 / 14.1
9.   Line Attenuation:   5.3 / 6.5

[Ronski]

I've had FTTC for nearly three years now, I've seen my upload slip from 12 to around 6, with an attainable of less than that. It's not all cross talk related, as during a recent power cut my upstream attainable showed around 8, unless my main disturber also has a UPS which is unlikely.

[MrBelter]

Maybe so but 22,000 on a 5.3db line attenuation clearly isn't right and the sudden drop has me worried it is going to do it again and then clearly i am going to have problems.

[broadstairs]

It does seem strange. On my line currently due to DLM interference my up is 14993kbps with attainable of 23739 on an SNRM of around 12db. Prior to all my recent problems I had a solid 19995kbps up on a lower SNRM around 9db.

Stuart

[PhilipD]

Hi

It may also be the case, because your connection is good and you are close to the cabinet, a change at some point has reduced your upstream power, so your modem is not shouting so loud, so your signal to noise is lower and your max attainable rate reduces (based on the lower power) and is showing as a bit above 20.  This is probably completely by design by the DLM and your modem, in that you only "shout" as loud as is needed, which has the benefit for other users (on longer lines) as it reduces cross-talk so those users achieve a better speed.

Do you know what the power output was then and now?

Regards

Phil

[MrBelter]

I have no idea on the power sorry but your explanation does sound really plausible and to be honest i would be happy if that was the case even though i did like having a 9db noise margin, i always felt it gave you some room to breathe if owt went wrong.

Hopefully you are right, thanks for the info

[MrBelter]

I'm not sure it is of any interest but 8 days later and not a lot has happened, i guess i'll see if there is a change when the BT enforced 14 day reboot/resync happens.

5.   VDSL uptime:   8 days, 02:36:00
6.   Data Rate:   19993 / 79999
7.   Maximum Data Rate:   21930 / 110281
8.   Noise Margin:   6.6 / 14.1
9.   Line Attenuation:   5.1 / 6.4