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

[#1]

Graph no. 885: 28 Jan,12:00-14:00
Graph no. 886: 28 Jan,14:00-16:00
Graph no. 887: 28 Jan,16:00-18:00
Graph no. 888: 28 Jan,18:00-20:00
Graph no. 889: 28 Jan,20:00-22:00
ThinkBroadband Quality Monitor @2251
Router Stats @2252
Uptime: 11 days, 14:52:19
DSL Type: ITU-T G.992.5
Bandwidth (Up/Down) [kbps/kbps]: 447 / 1,642
Data Transferred (Sent/Received) [GB/GB]: 2.52 / 14.46
Output Power (Up/Down) [dBm]: 12.0 / 16.3
Line Attenuation (Up/Down) [dB]: 37.2 / 66.5
SN Margin (Up/Down) [dB]: 10.5 / 10.4
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / TSTC
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): -
Error Seconds (Local/Remote): 56,139 / 11
FEC Errors (Up/Down): 24,735 / 24,744,473
CRC Errors (Up/Down): 784 / 472,973
HEC Errors (Up/Down): 1,437 / 582,756

[#2]

Graph no. 890: 28 Jan,22:00-00:00
Graph no. 891: 29 Jan,00:00-02:00
Graph no. 892: 29 Jan,02:00-04:00
Graph no. 893: 29 Jan,04:00-06:00
Graph no. 894: 29 Jan,06:00-08:00
BT Broadband Checker and Performance Test @0804
BTW Performance Test @0804
ThinkBroadband Quality Monitor @0819
Router Stats @0825
Uptime: 12 days, 0:25:37
DSL Type: ITU-T G.992.5
Bandwidth (Up/Down) [kbps/kbps]: 447 / 1,642
Data Transferred (Sent/Received) [GB/GB]: 2.57 / 14.73
Output Power (Up/Down) [dBm]: 12.0 / 16.3
Line Attenuation (Up/Down) [dB]: 37.2 / 66.5
SN Margin (Up/Down) [dB]: 11.0 / 11.4
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / TSTC
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): -
Error Seconds (Local/Remote): 58,414 / 11
FEC Errors (Up/Down): 24,906 / 26,170,061
CRC Errors (Up/Down): 786 / 488,372
HEC Errors (Up/Down): 1,439 / 596,241

[#3]

Graph no. 895: 29 Jan,08:00-10:00
Graph no. 896: 29 Jan,10:00-12:00
Graph no. 897: 29 Jan,12:00-14:00
Graph no. 898: 29 Jan,14:00-16:00
Graph no. 899: 29 Jan,16:00-18:00
Graph no. 900: 29 Jan,18:00-20:00
Graph no. 901: 29 Jan,20:00-22:00
ThinkBroadband Quality Monitor @2244
Router Stats @2249
Uptime: 12 days, 14:49:35
DSL Type: ITU-T G.992.5
Bandwidth (Up/Down) [kbps/kbps]: 447 / 1,642
Data Transferred (Sent/Received) [GB/GB]: 2.78 / 16.11
Output Power (Up/Down) [dBm]: 12.0 / 16.3
Line Attenuation (Up/Down) [dB]: 37.2 / 66.5
SN Margin (Up/Down) [dB]: 10.8 / 10.8
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / TSTC
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): -
Error Seconds (Local/Remote): 61,398 / 11
FEC Errors (Up/Down): 26,952 / 28,480,462
CRC Errors (Up/Down): 891 / 510,975
HEC Errors (Up/Down): 1,625 / 625,267

[#4]

Graph no. 902: 29 Jan,22:00-00:00
Graph no. 903: 30 Jan,00:00-02:00
Graph no. 904: 30 Jan,02:00-04:00
Graph no. 905: 30 Jan,04:00-06:00
Graph no. 906: 30 Jan,06:00-08:00
Graph no. 907: 30 Jan,08:00-10:00
Graph no. 908: 30 Jan,10:00-12:00
ThinkBroadband Quality Monitor @1204
Router Stats @1206
Uptime: 13 days, 4:07:04
DSL Type: ITU-T G.992.5
Bandwidth (Up/Down) [kbps/kbps]: 447 / 1,642
Data Transferred (Sent/Received) [GB/GB]: 2.88 / 16.77
Output Power (Up/Down) [dBm]: 12.0 / 16.3
Line Attenuation (Up/Down) [dB]: 37.2 / 66.5
SN Margin (Up/Down) [dB]: 10.6 / 11.3
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / TSTC
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): -
Error Seconds (Local/Remote): 63,736 / 11
FEC Errors (Up/Down): 27,395 / 29,788,251
CRC Errors (Up/Down): 897 / 543,107
HEC Errors (Up/Down): 1,629 / 650,268

[#5]

Well there doesn't seem to be any progress here Richard!  I've asked several times about any updates to your ticket and not seen any response on that. This really needs to be progressed otherwise I suspect nothing else is likely to happen.
There is still the problem of the BT IP Profile being reported by the BTw Speedtest being wrong which without any adequate explanation suggests an exchange fault to me.
Also during daytime over the weekend, providing there is no Interference present (ie, your DS SNRM is steady above 11dB) I woulddo a graceful disconnect stay off for 10 minutes and then power up again, to recover your lost sync speed.
After you've done so, posting the results from the telnet command xdsl debug bitloadinginfo again might be useful.

[#6]

Graph no. 909: 30 Jan,12:00-14:00
Graph no. 910: 30 Jan,14:00-16:00
Graph no. 911: 30 Jan,16:00-18:00
Graph no. 912: 30 Jan,18:00-20:00
Graph no. 913: 30 Jan,20:00-22:00
Graph no. 914: 30 Jan,22:00-00:00
Router Stats @0108
Uptime: 13 days, 17:09:56
DSL Type: ITU-T G.992.5
Bandwidth (Up/Down) [kbps/kbps]: 447 / 1,642
Data Transferred (Sent/Received) [GB/GB]: 3.01 / 17.62
Output Power (Up/Down) [dBm]: 12.0 / 16.3
Line Attenuation (Up/Down) [dB]: 37.2 / 66.5
SN Margin (Up/Down) [dB]: 10.8 / 10.4
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / TSTC
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): -
Error Seconds (Local/Remote): 64,856 / 13
FEC Errors (Up/Down): 29,478 / 30,777,662
CRC Errors (Up/Down): 952 / 549,275
HEC Errors (Up/Down): 1,719 / 658,750

[#7]

Quote from: Anotherone

Well there doesn't seem to be any progress here Richard!  I've asked several times about any updates to your ticket and not seen any response on that. This really needs to be progressed otherwise I suspect nothing else is likely to happen.

I'm really not sure what more can be done... the ticket will be left open for another week and as long as the present service is maintained, I doubt there will be any particular reason for lodging a complaint... my broadband is within the limitations published on the BT Broadband Availability Checker webpage and when I see some of the problems from which others posting in this community forum are suffering, I think there is plenty of reason for making do with what I've got... for now... at least...
Thank you for your encouragement... it has been an interesting learning experience...

[#8]

I'll comment more when I see the Bitloading after a daytime resync with no Interference.

[#9]

Graph no. 915: 31 Jan,00:00-02:00
Graph no. 916: 31 Jan,02:00-04:00
Graph no. 917: 31 Jan,04:00-06:00
Graph no. 918: 31 Jan,06:00-08:00
Graph no. 919: 31 Jan,08:00-10:00
Graph no. 920: 31 Jan,10:00-12:00
Graph no. 921: 31 Jan,12:00-14:00
Graph no. 922: 31 Jan,14:00-16:00
Graph no. 923: 31 Jan,16:00-18:00
Router Stats @1814
Uptime: 14 days, 10:15:37
DSL Type: ITU-T G.992.5
Bandwidth (Up/Down) [kbps/kbps]: 447 / 1,642
Data Transferred (Sent/Received) [GB/GB]: 3.08 / 18.79
Output Power (Up/Down) [dBm]: 12.0 / 16.3
Line Attenuation (Up/Down) [dB]: 37.2 / 66.5
SN Margin (Up/Down) [dB]: 10.9 / 11.6
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / TSTC
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): -
Error Seconds (Local/Remote): 68,876 / 13
FEC Errors (Up/Down): 30,426 / 32,563,298
CRC Errors (Up/Down): 956 / 596,603
HEC Errors (Up/Down): 1,728 / 707,345