"Bursts" of sync loss

[#1]

For a 62dB attenuation, my line is relatively stable but it suffers bursts of sync loss at the moment (since 15 March, which coincided with street light replacement along the last half-mile stretch to my cabinet ). There was some noise on a quiet line test, if you waited long enough , and two OR visits found nothing - though the second engineer insisted on fitting a new filter, then crimped a couple of bits of wire to the extension for my modem as it would no longer reach.
The latest burst was yesterday and my IP monitoring (check at 5min intervals - for opendns lookup monitoring) shows:
May  4 2014 @ 10:30:00  -  IP address set to 87.112.159.227
May  8 2014 @ 01:51:23  -  IP address set to 146.90.160.247
May  8 2014 @ 02:21:28  -  IP address set to 87.112.189.79
May  8 2014 @ 02:51:36  -  IP address set to 87.114.5.27
May  8 2014 @ 03:21:44  -  IP address set to 87.115.19.84
May  8 2014 @ 04:21:59  -  IP address set to 146.200.172.72
May  8 2014 @ 04:42:03  -  IP address set to 91.125.97.3
May  8 2014 @ 04:52:09  -  IP address set to 87.114.97.111
May  8 2014 @ 05:22:16  -  IP address set to 87.112.34.214
May  8 2014 @ 05:52:24  -  IP address set to 46.208.130.187
May  8 2014 @ 06:22:34  -  IP address set to 87.113.28.158
May  8 2014 @ 06:52:42  -  IP address set to 87.113.85.47
May  8 2014 @ 07:22:51  -  IP address set to 87.112.19.252
May  8 2014 @ 07:52:58  -  IP address set to 87.113.19.97
May  8 2014 @ 08:23:04  -  IP address set to 87.113.143.167
May  8 2014 @ 08:53:11  -  IP address set to 87.115.167.42
May  8 2014 @ 09:23:20  -  IP address set to x.x.x.x  - this is still active
So, after 3d 15h 21m, there is a drop at 30 minute intervals (with 2 exceptions!). I know the trigger for this periodic drop - a 1571 phone that goes "off-hook" at 30min intervals to detect the interrupted dial-tone which can result in a >4dB drop - but this was not disconnected during the 87hr gap (only the uplink is affected, btw) and I cannot yet get routerstats to work with wine/mint  . When unstable, making/answering calls while the 1571 phone is disconnected causes the sync to drop, but ringing is not consistent.
I also log filtered modem stats at hourly intervals (tones above 153 are infrequently used) and the latest was:
**** 9 May 2014 at 09:00:01 ****
near-end interleaved channel bit rate: 2926 kbps
far-end interleaved channel bit rate: 539 kbps
near-end FEC error interleaved: 3909
near-end CRC error interleaved: 60
near-end HEC error interleaved: 338
far-end FEC error interleaved: 61568
far-end CRC error interleaved: 65504
far-end HEC error interleaved: 0
ADSL uptime    23:41:18
noise margin downstream: 7.6 db
attenuation downstream: 61.8 db
noise margin upstream: 8.0 db
attenuation upstream: 37.9 db
carrier load: number of bits per symbol(tone)
tone  0- 31: 00 00 00 03 56 88 99 99 99 99 98 88 77 66 44 32
tone  32- 63: 06 89 aa aa ba 9b b5 3a bb bb cc ab bc bb ba bc
tone  64- 95: ac bb bb a0 9b bb bb 8a aa a9 8a aa 89 89 69 79
tone  96-127: 99 88 88 66 77 74 67 67 66 65 55 66 44 55 56 55
tone 128-159: 00 05 50 33 55 55 04 40 00 00 00 00 00 00 00 00
tone 160-191: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Unfortunately, connecting the modem-router to the master socket involves laying a "trip hazard" of a mains extension lead and a 15m long ethernet cable across and along the main "pathways" through the house to provide normal computer usage.
I have tried plugging the TD8816 modem-router cables into a 585v7 for a while and the drops stopped ....... and didn't restart when returning to the (still powered) TD8816 an hour or so later .
Any suggestions on how to progress?
Phil

[#2]

Quote

I have tried plugging the TD8816 modem-router cables into a 585v7 for a while and the drops stopped ....... and didn't restart when returning to the (still powered) TD8816 an hour or so later Huh? . Any suggestions on how to progress?

That would suggest the router was at fault there.
It looks like the connection is stable again now, which router do have connected up at the moment?
<img src="http://community.plus.net/visualradius/generated/image13996257612444.png"/>

[#3]

Adam,
My first thought, also, as it is a warranty replacement for the one I bought, which failed after a few months (suffered SNRM droop!). However, it is the phone that triggers the SNRM drops that cause the re-sync - plugged directly into the master socket "openreach" filter.
The "graph" looks to match the data I have .
Currently, I'm using the TD8816 and this has been up from before 28th April (my modem stats logs start then), so it's been quite good.
April 24th was also a bad day, though there are a couple of  "forced" changes to get a decent upload sync (from 120kbps, I think):
Apr 24 2014 @ 16:52:07  -  IP address set to 87.114.126.95
Apr 24 2014 @ 17:22:20  -  IP address set to 87.112.31.200
Apr 24 2014 @ 17:42:23  -  IP address set to 91.125.227.247
Apr 24 2014 @ 18:38:20  -  IP address set to 91.125.138.176
Apr 24 2014 @ 18:48:23  -  IP address set to 91.125.113.110
Apr 24 2014 @ 19:33:31  -  IP address set to 87.112.202.12
Apr 24 2014 @ 19:43:33  -  IP address set to 46.208.115.246
Apr 24 2014 @ 19:53:39  -  IP address set to 146.90.173.163
Apr 24 2014 @ 20:03:42  -  IP address set to 46.208.132.42
Apr 24 2014 @ 20:33:47  -  IP address set to 87.115.84.232
Apr 24 2014 @ 20:54:00  -  IP address set to 46.208.213.233
Apr 24 2014 @ 21:04:02  -  IP address set to 31.185.159.58
Apr 24 2014 @ 22:34:16  -  IP address set to 87.112.76.224
Apr 24 2014 @ 23:04:23  -  IP address set to 87.112.33.229
Apr 24 2014 @ 23:39:33  -  IP address set to 31.185.232.20
I will experiment with the 585 and see if I can log similar IP and modem data, then try that for a few weeks.
Phil
Edit: as of Midday, the 585 is now in service.

[#4]

Not much change going from TD8816 to 585. The 585 ran fairly well until 0600, then a series of resyncs until 0950.The other problem with the 585 is that it is more "aggressive" with the uplink, so attempts to run at 700kbps, stealing capacity from the downlink and that makes it less reliable. Currently running at 2179/515kbps and 10/12db SNRM with large negative spikes on the uplink SNRM (up to 4.5dB, graph attached); the downlink variance is 0.5dB.
As the TD8816 appears to be better, I'm going back to see how that performs under the current conditions.
Phil
TD8816 sync at 3062/587kbps and 8.6/7.2dB SNRM 

[#5]

Shortly after the previous post there were 5 re-syncs before midnight, then stability for 1.5 days and it has now been running with little SNRM variation (approx 0.5dB) for over 8 days at 3/0.53Mbps - so I'm happy again
Phil

[#6]

Looks like it's been stable since the re-connect on the 13th
As shown below:
<img src="http://community.plus.net/visualradius/generated/image14006897208334.png"/>
If there are any further issues just let us know!