Poor downstream sync

I am trying to help an elderly friend of the family, she is in her mid eighties, with her ADSL broadband.

Downstream is very poor (704 kbps), upstream is as expected (760 kbps), distance from the exchange by road is approx. 2km. More complete stats are shown below. The BT Wholesale checker shows an expected Downstream Range of 5.5 to 7.5 Mbps.

I have taken a Billion 8800NL round and managed to get a graph from DSLStats which seems to show very high attenuation at higher frequencies (not sure how to post an image to this forum).

She has had Openreach visit a few times in the past but they have not resolved the problem and she stopped progressing it due to a period in hospital.
They are due to visit again in a few days and I will be present.
I have checked the wiring in the house and it all seems in order to me.
The outside cables are all underground.

Does anybody know what sort of faults can cause this sort of issue?

DSL Mode: ADSL2

Line Attenuation (dB) D/U: 37.5 / 22.8
Conn. Speed (kbps) D/U: 704 / 760
SNR Margin (dB) D/U: 2.9 / 6.0
Power (dBm) D/U: 0.0 12.7
Interleave D/U: 1 / 1

Pete

Does her landline phone work? One wire of the pair disconnected between her and the exchange can cause very low broadband speeds, but is accompanied by a complete loss of phone service.

Edited by RobertoS (Thu 14-Jun-18 18:28:07)

No problems at all on her landline, she uses it most days to both make and receive calls.
A 17070 Quiet Line test is clear, no noise is heard.

Any alarms or other devices connected to the line that may not have a filter on them?

Do the stats improve when using the test socket at all? And you've verified all extensions stop working when the test socket is exposed

No alarms or devices connected the line, there was an extension star wired before the master socket, I have disconnected the extension.

The master socket is quite old, no test socket.
I have unscrewed it and disconnected the one remaining extension and plugged the router directly in using a new cable and filter and also with no filter, it made no difference to the sync speeds.

When you disconnected the star-wired extension, did you disconnect it at the point of branching off, or at the user end of it? I expect you did it at the branch but I'm double-checking .

I disconnected the star wired extension where it branched off at the join between the incoming external black cable and the internal white cable going to the master socket..

Sync might have been banded and not change, so the impact on all the figures is what needs to be looked at

Banded sync would have a telltale high SNR though.