How to raise IP Profile

[#1]

For several years I have been synced at 5500 and getting dl speeds of 4.5mbps.  More recently I requested that my upload speed was uncapped and upload speeds increased from 368kbps to 800kbps.  This didn't seem to have any adverse effects to the dl speed.
However, for the past month I can't sync above 3744kbps and am therefore only getting 3mbps dl.  I have run the BT speed test thing that has confirmed my dl sync is reduced. 
I have monitored my modem and it was connected without drops for over a week but still my speed has not increased.
How can I get back to the speeds I used to have?
As an aside, I was thinking of swapping to fibre.  BT are a total joke, they set a date my cabinet is to be upgraded and then when the date arrives, shift it forward another 3 months.  This has been happening for a year now

[#2]

Please post the stats from your router - noise margin, speeds and attenuation

[#3]

Connection Status   Connected
Us Rate (Kbps)   1064
Ds Rate (Kbps)   3744
US Margin   6
DS Margin   15
Trained Modulation   ADSL2Plus
LOS Errors   0
DS Line Attenuation   50
US Line Attenuation   29
Peak Cell Rate   2509 cells per sec
CRC Rx Fast   0
CRC Tx Fast   0
CRC Rx Interleaved   15
CRC Tx Interleaved   0
Path Mode   Fast Path
BT speedtest reports my IP Profile to be 3.3Mbps
I know the DS margin is low, but like I said the modem has been stable and connected for over a week until I switch it off by accident on Sunday.
Cheers

[#4]

At 15dB, the DS margin is, in fact, high, not low.  It's possible that the exchange thinks your line has been unstable and has increased the target SNR margin and this would accound for a reduction in DS sync (Rate).

[#5]

By low, I mean a bit crap.  But it is a constant and stable crap.  I changed the microfilter  a week ago and like I say it was connected without dropping for more than 7 days, what triggers an increase in the profile? 
I know why the profile can be reduced but my question is how to get it increased.
Thanks

[#6]

Since when does carp need to be censored?  This forum is obviously frequented by lots of under 7's

[#7]

A constant and steady connection (with low error rate) should, in theory, eventually get the margin back to where it should be.
Lots of disconnects OR excessive error counts will force the margin higher (speed lower).
You can either sit back and cross your fingers (maybe there was a brief spell of 'interference' that caused the raised margin / lowered speed) or, if you're lucky a staff member may be able to check the connection logs and, possibly, do a reset (if all looks well from their end).  The only worry is how to explain why the DLM seems to have thought your line was unstable.

[#8]

I'll try waving my arms to catch the attention of  a staff member then. 

[#9]

Hi cossack101,
The line may not necessarily be stable below 15dB, in which case the DLM has done its job. Can you tell me if you're using any extension cables/sockets? Do you have a test socket you can plug into?
Jojo

[#10]

Hi Jo,
I'm not using any extensions and am plugged into the only socket in the house.  It doesnt have a test socket, but is using a brand new microfilter.  I fitted the new filter last week after having the slower speeds for a while.
Cheers

[#11]

HI cossack101,
I could reset the SNR to 6dB, which would bring your sync rate back up. The downside to this is that it could still go back up to 15dB as we've no idea what caused it. If that happened then we couldn't do anything about it for a further 10 days. The main problem we face when it comes to raising a fault is that currently, although lower than it has been, your sync rate falls within expected limits. I can try it, but just wanted you to be aware of the possibilities.
Jojo

[#12]

Has the fact that my download has been uncapped had any effect on the situation?  I'd rather than the increased download speed over the marginal upload speed gain.  These problems did start after my upload was increased but not precisely at the same time.
Cheers

[#13]

I doubt that, to be honest.

[#14]

Well I've left it a month and my speed has not improved by itself.  Would somebody be able to reset my SNR to 6db as suggested above by JoJo, so I can see if I can get back to the speed I used to have?
It occurs to me that my speed drop coincided with my local cabinet upgrade to fibre. Any chance an engineer tweaked something in error? I've not changed my hardware or wiring in years.
Cheers

[#15]

No Plusnet Digital Care staff on at a weekend, but if you can post your current ADSL LIne stats from your modem/router, the results of a BT Speedtest (Diagnostic) and post your Current Line speed we can see what's been happening. Has your modem/router been on 24/7 and have there been any re-boots or sync drops?