'Normal' evening SNRM drop/flat twisted pair RJ11 cable.

[#1]

3 non-requested resyncs this morning - 0915, 1037 and 1245, each time reconnecting at around 12Mbps/3dB.
Are these CRT-initiated drops as a response to this thread (daylight hours are when I reckon not to be at risk of connection drops at the moment?  :()

[#2]

As Anotherone has said, there isn't much we can add from here that you haven't already either worked out or already know about your line!
We've not performed any testing on your line (there isn't actually a fault ticket open), so the drops shouldn't be caused by us.

[#3]

OK, thanks Chris - at this rate it won't be long before there is a fault ticket opened! 

[#4]

Might always be work in the local exchange or your Cab, possibly disturbed things, particularly is there's any work going on to install a Fibre Cab anywhere near you. If it were intrusive line testing (unlikely as Chris has already mentioned) it would be just under 3 minutes each time, around 2m45).  Do the Quiet Line Test 17070 option 2 and check you don't have any crackles or other noises.
Have you reported that street light yet?

[#5]

Complete silence on quiet line test, am in process of finding an alternative contact addy for reporting street lamp malfunctions because the 'official' sheff.gov.uk site for fault reporting takes you so far and then stops (nothing to do with broadband, more to do with the number of half-finished, half,working street lamps in Sheffield at the moment I suspect.)
Some days is good days.............

[#6]

Relative stability has broken out since the DLM decided (again) that 6dB was a more appropriate SNRM target for my connection a few days ago - a couple of unexpected daytime drops even at this margin since then which may be due to BTOR playing around somewhere in the area, but currently up for 24 hours, and HEC errors back to thousands rather than hundreds of thousands during evening hours (very few during daylight hours.)
Decided to check for possible sources of interference using a MW radio tuned to around 600KHz :
Permanently lit street lamp : NIL (just hope my neighbours didn't spot me!  :D)
Old multi-voltage output PSU used to power home weather station: NIL
Mobile phone charger: NIL
Electric shaver charger: NIL
Cordless phone/answering machine base station: NIL
PSU for old Netgear router: Slight humming
PSU for DAB radio/alarm clock: LOUD INTERFERENCE
New Hudl 2 charger: LOUD INTERFERENCE
TG582n router: TICKING, presumably from WiFI
TG582n PSU: LOUD INTERFERENCE.
The last is of most concern, partly because it's new, but also because it's on 24/7 and only a couple of feet away from the router..
In each case the interference was only picked up with the radio a couple of inches or less away from the device - does anyone have a view as to whether this constitutes a fault which is likely to be causing problems, or merely a characteristic of some modern lightweight PSU's which just has to be lived with?

[#7]

I wouldn't worry, a couple of inches away you'll always pick up something as they'll all be Switched Mode PSUs except possibly the old Netgear one which is why you only got a slight hum.
As long as it's not radiating from devices like the DAB radio and HUDL when you are further away, shouldn't be an issue.

Quote

Permanently lit street lamp : NIL (just hope my neighbours didn't spot me!

That's always a good one, I have been known to be wandering up and down the road after dark in the past and stood by telephone/power poles with a radio emitting loud buzzing noises (who is that loony?)

[#8]

Thanks Anotherone - I'll lay the old radio back to rest in the drawer full of old bits of kit from whence it came! 
(Regarding holding up hissing small rectangular black objects up against street lamps, I did ponder whether it would look more suspicious at night rather than during daylight hours - chose the latter, and so far not seen any scary looking folk in white coats..... :-\)

[#9]

It's could be the one's in blue pointy hats you might really have to worry about 

[#10]

Oh dear, the new cable/new TG582n arrangement has gone from slightly perplexing to very worrying - a couple of days ago the target SNRM increased from 6 to 9dB, and after another drop about an hour ago it is now 12dB, with corresponding drops in sync speeds.
Router stats as of now:
Uptime: 0 days, 0:58:26   
DSL Type: ITU-T G.992.5   
Bandwidth (Up/Down) [kbps/kbps]: 1,217 / 8,242   
Data Transferred (Sent/Received) [MB/MB]: 35.43 / 640.36   
Output Power (Up/Down) [dBm]: 12.8 / 0.0   
Line Attenuation (Up/Down) [dB]: 16.8 / 37.0   
SN Margin (Up/Down) [dB]: 5.9 / 13.3   
System Vendor ID (Local/Remote): TMMB / ----   
Chipset Vendor ID (Local/Remote): BDCM / IFTN   
Loss of Framing (Local/Remote): 44 / 0   
Loss of Signal (Local/Remote): 5 / 0   
Loss of Power (Local/Remote): 0 / 0   
Loss of Link (Remote): -   
Error Seconds (Local/Remote): 180 / 0   
FEC Errors (Up/Down): 0 / 1,187 
CRC Errors (Up/Down): 1 / 5   
HEC Errors (Up/Down): 3 / 23
Quiet line test still silent, errors seemed to be very low during the day at 6dB, and not unreasonable during the evening, but the DLM clearly sees it differently.
Will change the router back to the old Netgear this morning, and the extension cable back to the old untwisted pair cable 24 hours later - I'll then have restored the exact arrangement which worked so reliably for years (with the margin tweaked from 3 to 5), although I won't of course be able to use my Wifi device. Both of my disconnections will be of the 'graceful' variety.
Does anyone have any idea how long the DLM is likely to take to respond favourably if these changes do actually rectify the problems I now have with my connection?

[#11]

There must be something going on with your connection that you are so far unaware of. I wouldn't swap modem/routers just yet.
Download and install RouterStatsLite.
Install it in C:\. I'll post some setup notes in a moment. But also login to your TG582n and have a look at the logs and post any entries that refer to xDSL.

[#12]

I do have Routerstats installed, and capturing some data in text files, but the PC is shut down overnight so I've not got anything relating to this morning's events. The following is the router's event log:
Info  Nov 26 09:54:12 LOGIN User admin logged in on [HTTP] (from 192.168.1.64)

Info  Nov 26 09:51:43 LOGIN User admin logged in on [HTTP] (from 192.168.1.64)

Info  Nov 26 09:02:22 SNTP Synchronised to server: 212.159.6.10

Info  Nov 26 09:00:36 LOGIN User admin logged in on [HTTP] (from 192.168.1.64)

Info  Nov 26 08:32:11 LOGIN User admin logged in on [HTTP] (from 192.168.1.64)

Error  Nov 26 08:23:12 FIREWALL icmp check (1 of 1): Protocol: ICMP Src ip: 123.205.159.146 Dst ip: 146.90.58.49 Type: Destination Unreachable Code: Port Unreacheable

Info  Nov 26 08:13:16 LOGIN User admin logged in on TELNET (192.168.1.64)

Info  Nov 26 08:12:55 LOGOUT User admin logged out on TELNET (192.168.1.64)

Info  Nov 26 08:09:23 CONFIGURATION saved by TR69

Info  Nov 26 08:08:38 FIREWALL event (1 of 1): modified rules

Info  Nov 26 08:08:38 FIREWALL event (1 of 1): created rules

Warning  Nov 26 08:08:38 PPP link up (Internet) [146.90.58.49

Info  Nov 26 08:08:38 FIREWALL event (1 of 2): deleted rules

Info  Nov 26 08:08:38 PPP CHAP Receive success (Internet)

Info  Nov 26 08:08:38 PPP CHAP Receive challenge from rhost PTW-AG01 (Internet)

Info  Nov 26 08:08:37 PPP CHAP Receive challenge from rhost bras-red9.sf (Internet)

Info  Nov 26 08:08:34 xDSL linestate up (ITU-T G.992.5; downstream: 8242 kbit/s, upstream: 1217 kbit/s; output Power Down: 20.4 dBm, Up: 12.8 dBm; line Attenuation Down: 37.0 dB, Up: 16.8 dB; snr Margin Down: 12.1 dB, Up: 6.3 dB)

Warning  Nov 26 08:08:18 PPP link down (Internet) [46.208.84.79]

Info  Nov 26 08:08:08 xDSL linestate down

Info  Nov 26 08:07:38 xDSL linestate down

Info  Nov 26 08:07:20 FIREWALL event (1 of 1): modified rules

Info  Nov 26 08:07:20 FIREWALL event (1 of 1): created rules

Info  Nov 26 08:07:20 xDSL linestate down

Info  Nov 26 08:02:22 SNTP Synchronised again to server: 212.159.6.9

Error  Nov 26 07:41:10 FIREWALL icmp check (1 of 1): Protocol: ICMP Src ip: 115.201.38.195 Dst ip: 46.208.84.79 Type: Destination Unreachable Code: Port Unreacheable

Info  Nov 26 07:02:22 SNTP Synchronised to server: 212.159.6.9

Error  Nov 26 07:01:20 FIREWALL icmp check (1 of 1): Protocol: ICMP Src ip: 82.73.19.204 Dst ip: 46.208.84.79 Type: Destination Unreachable Code: Port Unreacheable

Error  Nov 26 06:55:53 FIREWALL icmp check (1 of 1): Protocol: ICMP Src ip: 123.25.39.83 Dst ip: 46.208.84.79 Type: Destination Unreachable Code: Port Unreacheable

Error  Nov 26 06:43:43 FIREWALL icmp check (1 of 1): Protocol: ICMP Src ip: 125.72.251.244 Dst ip: 46.208.84.79 Type: Destination Unreachable Code: Port Unreacheable

Error  Nov 26 06:37:18 FIREWALL icmp check (1 of 1): Protocol: ICMP Src ip: 182.129.227.240 Dst ip: 46.208.84.79 Type: Destination Unreachable Code: Port Unreacheable

Error  Nov 26 06:33:44 FIREWALL icmp check (1 of 2): Protocol: ICMP Src ip: 91.192.152.20 Dst ip: 46.208.84.79 Type: Time Exceeded Code: Time to Live exceeded in Transit

Error  Nov 26 06:04:11 FIREWALL icmp check (1 of 1): Protocol: ICMP Src ip: 176.123.216.43 Dst ip: 46.208.84.79 Type: Destination Unreachable Code: Port Unreacheable

[#13]

Is that the full version of RouterStats? That is a bit painful to set up properly, I can give you notes for that if you want. The Lite version does most of what is needed unless a fault is more complex, but this does sound like rather a bad connection problem or one that is getting disturbed when BT are doing work.
The web based log doesn't give as much data as can be got via Telnet, I'll post some info on that next then.

[#14]

Yes, full version, and yes, pure guesswork was used to decide what and how to capture! 

[#15]

I assume you know how to open a cmd window/prompt (I don't know which Windows version you are using). It may open in your Documents & Settings folder, or some seem to open in the system32 folder. Neither is a good place to go cluttering up with random files.
If you are familiar with moving around directories in a command prompt, go wherever is easiest/suitable for you, otherwise save the stuff in root, it's is easier to get at and not so much of an issue there. You can get to C:\ in My Computer or Windows Explorer easily to open the file afterwards.
Use the command......    cd C:\     to go there.
Use the following telnet command......   telnet -f events##.log 192.168.1.254
This copies the telnet output direct to the file events##.log
You can substitute the ## for a number, I usually do it after the file has been completed by doing a rename. I can then use the same command everytime which I have saved in a text file along with some other commands, I just do a copy and paste of the one I want.
Login using your default username and password (or customised one if you have created one)
At the prompt  enter.....     syslog msgbuf show hist=enabled
At the prompt type...      exit
Depending on the timeouts, you may only have a short time before the telnet connection times out. If so, just log in again.
You can open the log file in a text file reader (Notepad) and just copy and paste into a post.
If you are struggling with any of the above, ask away.