A high level of local noise such as MW radio pickup on a ring wire will reduce the sync. If that noise disappears as it may well do during the daytime then the result will show as a high target margin. You can't second guess what the target margin is without knowing a lot about the state of the internal wiring and it's susceptibility to noise pickup. The time of day the stats were taken and when it synced would offer some clue.

As I said in the post you wouldn't expect to see that sort of swing if the ring wire was isolated. OTOH you may well se it if there are extensions and the ring wires were not isolated in some way such as an iPlate, filtered faceplate, or newer type BT faceplate.

Hi and thanks for the clarification.

Update

Reconnected the Netgear router this morning, and it picked up at 12 dB (was 15) SNR, syncing at 3904 Kbps (was 3072) downstream and 832 Kbps (was 704) upstream. So, some unprompted improvement!

Contacted TTB and spoke to a very helpful and informative lady. She advised that in the last month there had been a number of resets, and there was evidence of interference, particularly between 21:20 last night and 07:30 this morning. She asked about the siting of the router, and I outlined the location, right next to the electricity distribution panel and the central heating control unit. Once we'd gone through all that it was clear that I need to look a re-siting the router and that at this stage there's no point in trying a manual reset.

Re-siting is not going to be easy: this is a 2nd foor flat with the master socket on the ground floor, although the extension line running from it is twisted, not flat, but the spec is not apparent. It emerges in the flat at the current router location, so relocation is going to be a challenge.

Thanks again for your input, it is much appreciated. There's clearly still some mileage to run for this situation!

Cheers

Hi kwikbreaks,

Just to let you know that I posted the latest on this topic a couple of minutes ago - see my update to XraySpex.

Thanks again for your input - it is really appreciated.

Cheers

Your modem's location is not good at all. The Consumer Unit is a nice source of RFI from all the circuits and switching and similarly te CH controller - you can get some nasty RFI spikes from there too.

Twisted pair in any form from the master to extension will have benefits - provided it is Cat5e/Cat6/CW1308 or similar. However, even twited pair is not totally immune to noise.

How well do you get on with the people where the mater socket is? Or is it a communal area? One solution might be to move your router there - either as a full router or in modem only mode and then run Cat5e back to your flat and connect into either a router or switch. That way, any potential noise sources on the cable run is unlikely to affect your connection.

Hi MHC, thanks for your response.

I now realise the original system installer has not done anyone any favours. I'm mulling over options at the moment. The master sockets are in a communal area, but they are adjacent to a communal aerial amplifier and the power supply for the slightly less adjacent remotely operated doorlock. The more I consider the EMI/ RFI aspects, the more of a disaster area the building appears to be. There again, it does seem to be the way things are going.

I think I'm going to have to do some experimenting. Locating the modem/ router in the communal area is not out of the question - the main task is going to be establishing a quiet area; I may have to resort to some sort of Farady cage arrangement.

Thanks again

Is the ringwire connected (terminal #3 on the master socket faceplate)? If so it is the most likely source of noise pickup and can safely be disconnected from the faceplate. Most modern phones don't need a ringwire and in any event ADSL filters re-establish one as there is a ring capacitor in them as well as the filter.

Edited by kwikbreaks (Thu 01-Jan-15 05:28:23)

Hi,

Just had a(nother) look at the (collective) master sockets. The incoming line is a multicore cable which runs into what I would call a breakout box, from which individual cables run to their respective master sockets.

I'm not touching the breakout box, and when I remove the faceplate on our socket to expose the test socket, only two conductors are connected (excluding the extension leads). It thus appears that there is no ring-wire connection at the master sockets, although I haven't checked any of the others.

So I'm now on the hunt for an EMI qiuet zone...

Thanks again and Happy New Year

The ring wire is the wire on terminal #3 on the faceplate which runs to your extension socket. Certainly don't touch any of the wiring going to the A and B connectors on the back of the master socket. If only #2 + #5 are connected then you don't have a ring wire.

It may be that your regular disconnects before were just the duff router. Did you mention you'd replaced the router and it had fixed the audible noise to your ISP. You can check if you have high local noise levels simply by checking the stats periodically - if local noise levels fall you'll see that as an increased noise margin and vice versa.

Edited by kwikbreaks (Thu 01-Jan-15 12:55:13)

Only two conductors connected to the back of the faceplate, ergo, no ring wire.

I'm monitoring the stats and we'll see what developes...

Cheers

There is only a 2 wire pair coming from the exchange for both the phone and the broadband. One of the functions of the master socket is to create the ring signal and send this down terminal 3 to the extensions. So you will only see 2 wires coming in and 3 wires going out.