Marginal broadband - weird stats - help needed

Hi all,

My neighbours broadband stopped working so I get to sort it out.....

Talktalk LLU, ADSL2+, 5km to exchange, two extensions in house, all filters correctly positioned.

For the last couple of years up to two weeks ago, their line was working fine with a sync speed of 1400 to 1500kbps using a zoom wireless modem connected to extension 1. This stopped syncing so stage one was to swap to the Talktalk modem. This synced on the extension but at only a speed of 400kbps. This got the broadband up and running again (no wireless though) but the speed drop suggested that something was still wrong.

I then moved to the master test socket and tried both modems there. Both would sync at 1400kbps which straight away made me think that the problem was in the wiring somewhere.

I removed both extensions from the master socket and reconnected extension 1 only with no bell wire. Sync speed at the end of extension was 400kbps whilst at the master socket was 1000kbps. This made me again think that the extension wire was rather suspicious and as there was a good chance that mice were nibbling on it, I moved to extension 2. Using this wire only and with extension 1 disconnected, very similar results were seen. Now I could understand one extension wire going faulty but both seemed rather strange to me so I started to look for another cause.

Stats from the master socket are as follow:
Sync: 1405 / 337
SNM: 15.5 / 15
Attenuation: 59 / 37

At the end of the extension they are something similar to:
Sync: 400 / 337
SNM: 15.5 / 15
Attenuation: 61 / 37

Now this is a long line with high attenuation which is struggling to work well. It wouldn't take much extra noise / attenuation to bring the sync speed down - such as the addition of the extensions. The drop from 1400 to 400 does seem quite a lot though. I also can't see what caused the drop in performance two weeks ago.

One thought that has gone through my head is that it is vaguely possible that someone at Talktalk put the line onto a 15dB margin from something smaller two weeks ago. This would drop the sync speed down as has been seen. I'll get my neighbour signed up to the Talktalk forum so that this can be confirmed or not.

Can anybody else think of anything I've missed? There doesn't appear to be any new electrical gadgets that would cause the drop in sync. For the record, I get 2.4Mb next door via Newnet (BT line) whilst the next neighbour gets 4Mb via Talktalk (he isn't very popular with us at the moment).

Any help / comments very gratefully received.

The thing that strikes me is the 2db attenuation increase with the extension wiring attached. Usually you'd be looking at a couple of hundred metres of wire to increase that much. I suspect somethings till not right with the extensions.

I wouldn't read too much into the attenuation increase as it seemed to vary by a dB or so each time I resynched. Initially I wasn't looking too carefully at all the stats so I can't be exact but I seem to remember seeing a figure of 57dB on the end of the extension at one stage which was less than at the master socket....

Does the kit report errors ? Is it possible that it's picking up a bit of REIN, these longer lines, with marginal sync rates are more susceptible.

REIN??

I'll check for errors when I look at the kit next.