It might not even be something in your home, it could be a neighbour, or anywhere on the route of your line back to the cabinet.

In reply to a post by lee111s:

It might not even be something in your home, it could be a neighbour, or anywhere on the route of your line back to the cabinet.

He is fully aware of that. The idea is to try and eliminate everything, part by part, starting with his own property and electronics. They to start looking for outside influences.

Yeah I realise that. The line goes stright down the road into the cab about 270m away. It doesn't pass any factories/sub stations or anything like that. I suppose it could be anything. How close does the line have to pass to be affected by the source?

In reply to a post by WelshWArrior:

BT have an BT Engineer booked for me next Tues AM because of the difference in attainable (68583) and actual sync rate (57935) but it would be nice to get to the bottom of it on my own

As BatBoy has said, in less detail, that huge difference has always been normal on FTTC when interleaving is applied. Pre-G.INP when interleaving was later removed by DLM then the sync rate would rise and the attainable fall so they became similar somewhere in between.

An engineer is unlikely to find a fault to do with that, but you may be lucky and he finds what is causing all the errors. However, in either case, I'd be worried about a charge, if the error cause is one of those recently suggested. Unless BT CS have guaranteed there won't be one.

Any more thoughts?

I suppose it could be anything. How close does the line have to pass to be affected by the source?

It depends, how strong is the source, does it have an easy path onto the network. i.e. a duff sky box connected to telephone line,
I've seen one of these blitzing a 300m radius no problems.

The cheapest and easiest way to hunt for culprits is to use a battery operated MW radio. Tune to around 612 ..... but the frequency may be different as it's affecting VDSL. Remember also, lots of stuff makes 'noises' you'll hear on the radio .... not always the culprit.

Hunting these things is dark ju-ju indeed

In reply to a post by lee111s:

That to me reads they do use it although don't simply call is SRA as they can use the algorythm to modify the interleaving depth too, without a retrain?

"The SRA is limited to tweaking the minimum and maximum data rates (banding), but the Openreach DLM algorithm can also modify the interleaving delays and impulse noise protection levels (and theoretically the TSNRM too)"

The use of the word "also" being key.

And also with SRA enabled the sync rate changes both up and down according to the amount of errors/noise, and can work on a fast path profile, infact a former ISP who i was with would enable sra on some users lines, if their modem was SRA compatible as an alternative to packet loss due to errors or having interleave applied, that ISP was UkOnline BE also tried to utilise it but the results of their trial weren't great, possibly had something to do with how they configured it


Additionally, that post was made in 2013, some 3 years ago. I note that Openreach did carry out some SRA trials along with vectoring so it's possible SRA in one form or another is in use.

I guess we'll wait and see what the OP comes back with.

Yep it's certainly a challenge

Post deleted by WelshWArrior