Please may I have an explanation of how the SNR affects broadband delivery?

[#1]

An excellent set of data there Richard (keep it coming), interesting that there's been no repeats of the odd behaviour we saw Thursday night/Friday.
There are three or four spikes on the Tx noise, which may be related to phone use, but I can't see how low they go on all the graphs because of the minimum value on the scale which may be of no consequence. Whilst errors are still high, at least the connection seems stable at present.
There is an overall trend of normal day/night changes in SNRM exacerbated by this non-twisted pair drop-wire but there are some other events I'll list later, which we need to discover more about.

[#2]

Quote from: Anotherone

Whilst errors are still high, at least the connection seems stable at present.

Not needing to frequently reboot the router is a new experience for me... having RouterStats monitoring the connection has been a real eye opener...
Thank you, Anotherone, for your persistence in getting me to this point in the evolution of my understanding about my ADSL connection... you have been very helpful...
Graph no. 50: 18 Nov,06:30-08:30
Graph no. 51: 18 Nov,08:30-10:30
Graph no. 52: 18 Nov,10:30-12:30
Graph no. 53: 18 Nov,12:30-14:30
Uptime: 5 days, 1:35:23
DSL Type: ITU-T G.992.5
Bandwidth (Up/Down) [kbps/kbps]: 447 / 1,657
Data Transferred (Sent/Received) [GB/GB]: 2.65 / 11.64
Output Power (Up/Down) [dBm]: 12.0 / 16.7
Line Attenuation (Up/Down) [dB]: 37.7 / 67.5
SN Margin (Up/Down) [dB]: 9.1 / 9.1
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / TSTC
Loss of Framing (Local/Remote): 18 / 0
Loss of Signal (Local/Remote): 2 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): -
Error Seconds (Local/Remote): 29,711 / 6
FEC Errors (Up/Down): 14,304 / 5,181,343
CRC Errors (Up/Down): 303 / 43,441
HEC Errors (Up/Down): 519 / 43,439

[#3]

Graph no. 54: 18 Nov,14:30-16:30
Graph no. 55: 18 Nov,16:30-18:30
Graph no. 55: 18 Nov,18:30-20:30
Graph no. 56: 18 Nov,20:30-22:30
Graph no. 57: 18 Nov,22:30-00:30
Uptime: 5 days, 10:34:59
DSL Type: ITU-T G.992.5
Bandwidth (Up/Down) [kbps/kbps]: 447 / 1,657
Data Transferred (Sent/Received) [GB/GB]: 2.91 / 12.62
Output Power (Up/Down) [dBm]: 12.0 / 16.7
Line Attenuation (Up/Down) [dB]: 37.7 / 67.5
SN Margin (Up/Down) [dB]: 8.9 / 7.1
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / TSTC
Loss of Framing (Local/Remote): 18 / 0
Loss of Signal (Local/Remote): 2 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): -
Error Seconds (Local/Remote): 32,302 / 9
FEC Errors (Up/Down): 15,301 / 5,511,904
CRC Errors (Up/Down): 381 / 46,644
HEC Errors (Up/Down): 674 / 46,791

[#4]

Quote from: Anotherone

Whilst errors are still high, at least the connection seems stable at present.

Stable it maybe... speed is the limitation... my speedcheck results are appended... pretty disappointing... really... as the OpenReach engineer explained, stability can only be achieved by reducing the speed... or words to that effect...
Graph no. 58: 19 Nov,00:30-02:30
Graph no. 59: 19 Nov,02:30-04:30
Graph no. 60: 19 Nov,04:30-06:30
Graph no. 61: 19 Nov,06:30-08:30
Uptime: 5 days, 18:30:59
DSL Type: ITU-T G.992.5
Bandwidth (Up/Down) [kbps/kbps]: 447 / 1,657
Data Transferred (Sent/Received) [GB/GB]: 3.19 / 13.51
Output Power (Up/Down) [dBm]: 12.0 / 16.7
Line Attenuation (Up/Down) [dB]: 37.7 / 67.5
SN Margin (Up/Down) [dB]: 8.9 / 8.9
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / TSTC
Loss of Framing (Local/Remote): 18 / 0
Loss of Signal (Local/Remote): 2 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): -
Error Seconds (Local/Remote): 33,172 / 9
FEC Errors (Up/Down): 15,659 / 6,343,274
CRC Errors (Up/Down): 382 / 48,588
HEC Errors (Up/Down): 675 / 48,385

[#5]

Well sorry, what the Openreach "engineer" said isn't always true. It depends on the cause on any instability in the first place.
At present, the problem with your download speeds here is that your BT IP profile is still at 0.75 and it should have gone up to 1.46 with that current sync speed. And as your line has been stable for nearly 6 days at this speed (despite the other issues) it distinctly looks like you have a stuck profile. Can you run the BT Diagnostic Speedtest again at around 3.00pm and if there's no change we'll see if we can get it looked at - but I have a trick up my sleeve for maybe getting the drop-wire dealt with as well depending on exactly what's going on here.
If we can address the spikes we are seeing on the Tx SNRM plot -
Are any of these likely to be phones calls (maybe an occasional Quiet Line Test as well  ) -
Friday 14th - ~0850, ~1218, ~1650, ~1709, ~1932.
Monday 17th - ~1449, ~1642
Tuesday 18th - ~0113, ~1153/1154, ~1258, ~1836, ~1853, ~1855, ~2230

[#6]

Quote from: Anotherone

At present, the problem with your download speeds here is that your BT IP profile is still at 0.75 and it should have gone up to 1.46 with that current sync speed. And as your line has been stable for nearly 6 days at this speed (despite the other issues) it distinctly looks like you have a stuck profile.

In my reply #65 on 09/11/2014, I posted the results of a BTW speedtest which indicated that the IP profile was 1.01 Mbps at that time... and I can see no correlation with outgoing phone calls...
Outgoing calls made at:
18/11/2014 08:57:40
18/11/2014 10:20:28
18/11/2014 10:54:18
Possible correlation with two incoming calls from a person on a mobile phone...
Precise times of the spikes on NoiseMargin-2014Nov18-1830.jpg chart are:
12:58:37
18:34:53
18:53:34
18:55:14
Correlated with Incoming calls at:
18/11/2014 12:58 from a landline
18/11/2014 18:34 from a mobile
18/11/2014 18:54 from a mobile (this was an accidental call that left a noisy message on the answer service... explanation added as an 'edit'...)
When I do a quiet test, I can see no effect on the router stats at all...
In another ADSL thread I read about a new Plusnet customer who has moved from TalkTalk and one of the reasons given for his service 'issues' is that Plusnet use BT exchange equipment whereas TalkTalk have their own equipment in his exchange... when I visit the TalkTalk website, it suggests to me that I might receive 1.6 Mbps using their LLU service... I know that my exchange is 21CN enabled and that a new FTTC cabinet has recently been installed close to the cabinet to which I am connected... my question now is, 'Do TalkTalk have a significant advantage over and above what BT Wholesale can provide at this moment in time?'
The reason for asking this question about TalkTalk is that, as a Plusnet customer, I get a small monthly referral fee for each new customer who signs up for a Plusnet service as the result of my recommendation and 'due diligence' means that I need to be ready with an accurate answer, as it applies to my exchange... (a referral might be a neighbour...)
Router Stats @ 12:30
Uptime: 5 days, 22:28:27
DSL Type: ITU-T G.992.5
Bandwidth (Up/Down) [kbps/kbps]: 447 / 1,657
Data Transferred (Sent/Received) [GB/GB]: 3.35 / 14.05
Output Power (Up/Down) [dBm]: 12.0 / 16.7
Line Attenuation (Up/Down) [dB]: 37.7 / 67.5
SN Margin (Up/Down) [dB]: 8.9 / 6.1
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / TSTC
Loss of Framing (Local/Remote): 18 / 0
Loss of Signal (Local/Remote): 2 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): -
Error Seconds (Local/Remote): 34,208 / 9
FEC Errors (Up/Down): 15,915 / 6,384,594
CRC Errors (Up/Down): 387 / 49,886
HEC Errors (Up/Down): 679 / 50,040
Graph no. 62: 19 Nov,08:30-10:30   
Graph no. 63: 19 Nov,10:30-12:30   

[#7]

Shortly after the 9th Nov BT Speedtest you mention, you had a couple of drops in connection and you also briefly tried your DSL-502T, if during any of those events you had a much lower sync speed (~850kbps) then the profile would have gone down. I can't tell if that was when you were using the 585 as you were monitoring Maximum Bandwidth and not the Current Bandwidth (sync speed).
Why it hasn't gone up is unclear which is why I asked you to run another BT Speedtest at ~3.00pm.
The fact that you can correlate some of the spikes with incoming calls is noted, and can you keep an eye on future ones.
With regards to TalkTalk, IMHO they have no significant advantage in relation to BTw 21CN equipment. 20CN equipment is another matter. TalkTalks equipment can go faulty just as easily as BTw's and IMHO you won't get the sort of support over there as you can get here.
It's always a trade-off between the type of service that you want (including extras), the price you are paying, and the type of service and support that you actually get.
Anyone with a line problem, especially when suffering the sort of interference issues that you are getting, will have the same sort of problems whichever ISP you use. The wires to the exchange do not change, and if you want to go to FTTC, any issues need to be resolved before that.
When the Interference is not present, your SNRM is around 9dB. This suggests that if it were around 6dB you would get a higher speed and profile to go with it.

[#8]

Quote from: Anotherone

Why it hasn't gone up is unclear which is why I asked you to run another BT Speedtest at ~3.00pm.

No change at 3pm... I'm on a webinar at the moment... will try again later...
Graph no. 64: 19 Nov,12:30-14:30
Router Stats @ 15:24
Uptime: 6 days, 1:22:09
DSL Type: ITU-T G.992.5
Bandwidth (Up/Down) [kbps/kbps]: 447 / 1,657
Data Transferred (Sent/Received) [GB/GB]: 3.49 / 14.72
Output Power (Up/Down) [dBm]: 12.0 / 16.7
Line Attenuation (Up/Down) [dB]: 37.7 / 67.5
SN Margin (Up/Down) [dB]: 8.8 / 8.1
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / TSTC
Loss of Framing (Local/Remote): 18 / 0
Loss of Signal (Local/Remote): 2 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): -
Error Seconds (Local/Remote): 37,470 / 9
FEC Errors (Up/Down): 17,282 / 6,418,065
CRC Errors (Up/Down): 390 / 53,949
HEC Errors (Up/Down): 686 / 54,859

[#9]

Hopefully Tony will look at this profile problem.

[#10]

Yes, I'm on it.
However, my line tests aren't giving the same IP profile that you see there. I'm doing a few more checks and i'll get back to you ASAP.
Thanks.

[#11]

It's not quite at 1400k, but it has improved. I've checked our side and that matches OK. So, if you please just drop the connection in about ten minutes and let us know if you have further problems, this would be great. We then need to monitor, and see how it performs to see if we can increase it further.
Tony

[#12]

Hang on don't drop it yet, when I looked at the last SNRM graph there was a lot of REIN present. Best to wait until it goes away.
I'm guessing Tony did an intrusive test at one point and the resync would have been at a lower speed because of the reduced SNRM due to the REIN

[#13]

Richard, can you post the latest SNRM graph and stats so we can see what it's doing at the moment?

[#14]

The router rebooted... and the appended speedtests reveal the result...
Graph no. 65: 19 Nov,14:30-16:12
Router Stats @ 17:08
Uptime: 0 days, 0:50:16
DSL Type: ITU-T G.992.5
Bandwidth (Up/Down) [kbps/kbps]: 444 / 1,714
Data Transferred (Sent/Received) [GB/GB]: 3.55 / 15.00
Output Power (Up/Down) [dBm]: 12.0 / 16.6
Line Attenuation (Up/Down) [dB]: 37.6 / 67.5
SN Margin (Up/Down) [dB]: 10.9 / 9.0
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / TSTC
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): 39,051 / 9
FEC Errors (Up/Down): 126 / 15,538
CRC Errors (Up/Down): 0 / 689
HEC Errors (Up/Down): 0 / 588

[#15]

Graph no. 66: 19 Nov,16:30-17:13