VDSL Drop outs

Hi All,

I've been fortunate by having FTTP for a good 10 years now, so I'm a little out of touch when troubleshooting ADSL/VDSL issues, I'm helping a friend out with his random dropouts. So for around a year now his internet connection would drop intermittently, at first it was down to a noisy line, you picked up the handset on the line that supplies the internet and it was very crackly. Openreach came and sorted that out, a little while later it did the same thing again, and now we are back at square one. The line seems quiet but the internet connection randomly drops. Openreach have been out multiple times, they are now saying that it's electrical interference causing it, first it was faulty power supplies in the LED lighting of a workshop, those got changed. I'm skeptical as when they repaired the noisy line, the engineer said he was struggling to find good pairs to the cabinet and picked the best one. The master socket has been replaced, the modem and router has been replaced, all doing the same.

The equipment we have in place is a Draytek 2862 with 4G fail over.

I looked at the DSL stats and it says the following:

ATU-R Information





         Type: VDSL2
         Hardware: Annex A
         Firmware: 07-07-09-05-01-07
         Power Mngt Mode: DSL_G997_PMS_L0
         Line State: SHOWTIME
         Running Mode: 17A
         Vendor ID: 00000000 00000000




ATU-C Information



        Vendor ID: b5004244 434dc01c [BDCM]




Line Statistics
      Downstream             Upstream                
Actual Rate 34475 Kbps 8935 Kbps
Attainable Rate 47175 Kbps 8935 Kbps
Path Mode Fast Fast
Interleave Depth 1 1
Actual PSD 3. 4 dB 11. 1 dB


Near End                  Far End                   
Trellis ON ON
Bitswap ON ON
ReTx 0 1
SNR Margin 9 dB 6 dB
Attenuation 23 dB 25 dB
CRC 4 3212
FECS 0 s 18996 s
ES 1 s 2936 s
SES 0 s 1 s
LOSS 0 s 0 s
UAS 245 s 23014 s
HEC Errors 0 0
RS Corrections 0 0
LOS Failure 28 10
LOF Failure 0 0
LPR Failure 0 28
NCD Failure 0 0
LCD Failure 0 0
NFEC 254 32
RFEC 8 16


On the 29th of Jan the SNR margin on the downstream was 4dB, to me that's noisy?

Any suggestions as to what we should be looking at next? Other than keep on at BT?

4dB SNR is not noisy it actually indicates that te line is not bvery noisy.

If the system is happy running at 6dB SNR then it will over time drop to 5dB then 4dB and finally 3dB with each step contingent on being stable and reasonable error free. It could then stayat a lower level for weeks.

However, being at 3, 4 or 5 dB does mean than any transient or short term noise burst is mpore likely to cause a loss of sync. Although it may well sync back at teh same SNR or one step up.

Thanks.

Any idea what would be causing so many LOS Failiures?