Adam's wiring

[Adam]

As a quick hack I removed the junction box and simply twisted the orange cables together, and blue cables together. It has caused the BT "master" to not be connected, but there is still a connection to the BT fitted extension. Now I'm syncing at 4512 kbps with a SNR fluctuating around 9db - 13db, previously I would sync higher at first but end up at around 3900 kbps after a while and my SNR never made it above 6db.

[Rik]

That seems to demonstrate that a full re-wire will pay dividends. Go for it.

[Adam]

OK, here's my plan. I'm going to run 4-way (2 pair) cabling from the BT demarc to an NTE5 socket, then put in new extensions using 6-way cabling. I decided on continuing the 2 pair cabling to the NTE5 as it only supports 2 pair termination on the demarc point of the NTE5.

[Rik]

Sounds good to me. Run the extensions from the NTE5 with blue/white & white/blue on terminals 2 & 5, then see if you need a ring wire. If you do, usual code is orange/white on 3, but I'd then suggest using a filtered faceplate in place of the standard NTE5, and run a Cat5/6 lead to carry the signal for the router (or move the router to the NTE5 and run ethernet...).

[Adam]

The NTE5 I've got has a filter for the ring wire, so that may help somewhat. I plan on connecting the router to the NTE5 socket then running Cat6 to a few sockets around the house. As for the telephone cabling; does using 6-way instead of 4-way (2 pair) make much of a difference? (I have a large amount of 4-way cable but few of the 6-way)

Thanks in advance.

[Rik]

You only need two wires for a single line, Adam, three at most if you have to connect the ring wire, so a 4-wire cable is more than adequate.

[Adam]

You only need two wires for a single line, Adam, three at most if you have to connect the ring wire, so a 4-wire cable is more than adequate.

Thanks Rik. I've just found that 25m of the 4-way cabling I have is aluminium; that leaves me with 9m of 6-way cable, 6m of 4-way and 30m of Cat6. Luckily I can return the 25m cable as it was from B&Q, back to Maplin for more 4-way I think.

[Rik]

I need about 3.6km of copper, and BT to lay it for me.

[Lance]

Don't you mean fibre, Rik?

[Rik]

Copper would be a good start, Lance, but if they want to go for future proofing, who am I to argue? 

[Adam]

Copper would be a good start, Lance, but if they want to go for future proofing, who am I to argue? 

Then you have a similar problem as aluminium lines... BT will want to run ADSL to the house and will be unable to as it is fibre. I doubt they'll be able to comprehend supplying internet service straight from the fibre.

[Rik]

It will probably come as fibre to the cabinet, and local DSLAMs with a few hundred metres of copper. Wonderful thought, though why not go to the home and just change the modems we use?

[Adam]

Down: 7648 kbps
Line Attenuation: 37 db
Noise Margin: 9 db

[Rik]

That looks a bit better, doesn't it. Hopefully, unless the 9db margin is pinned, things will get better after a 14-day stable sync. I suspect the split pairs have been crippling your speed.

[Adam]

I'm still fitting it and just have the wires twisted together at the moment. Hopefully it'll be the same or better once it's all connected up. I'm using the aluminium cable as I found only 1db difference on the attenuation. If it stays stable and remains synced high I could develop an indifference to BT.

[Rik]

TBH, Adam, with the amount of aluminium you'll be using, I doubt it will have a great impact. A few km, though...

[Adam]

TBH, Adam, with the amount of aluminium you'll be using, I doubt it will have a great impact. A few km, though...

Indeed, I hear MK has had many issues due to aluminium lines. Interestingly I seem to get a better sync with the old cabling running direct from the linebox than I do with the new cabling in the same setup.

[Adam]

Tomorrow I'm going to try running some cable another, shorter, way as I think that is why the old is out performing the new. The old cabling is running about 10m and the new about 20m, and that seems to be taking about 2000 Kbps from the sync and reducing the noise margin to about 3db.

[Rik]

10m shouldn't make that much difference, Adam - is there any mains wiring adjacent to the phone run?

[Adam]

10m shouldn't make that much difference, Adam - is there any mains wiring adjacent to the phone run?

Not that I'm aware of, it passes heating pipes (though it is ran through conduit) but that's about it. The old cabling doesn't either, they both take different paths but neither has any sort of obvious areas that may cause interference.

[Rik]

I've got about 15m running from the NTE5 to a socket here where the router is. There's no detectable difference between the local socket, the master and the test.

For it to have that much impact on sync, there has to be a noise source somewhere along the way. Have you tried testing with a de-tuned AM radio?

[Adam]

I've got about 15m running from the NTE5 to a socket here where the router is. There's no detectable difference between the local socket, the master and the test.

I get different results from each socket, but the older cable seems to offer higher on all. The difference between the sockets is about the same for both cables though.

For it to have that much impact on sync, there has to be a noise source somewhere along the way. Have you tried testing with a de-tuned AM radio?

I can't think where there might be any noise; I tried running the cable direct from the BT linebox fitted to a length of new cable and I get around ~6700 with 5-9db SNR, yet the BT fitted extension with about 13m of old cable yields around ~7400 with an SNR of around 9-13db.

I'm currently connected using old cable (which is just twisted together near the linebox) going from the BT linebox to a BT fitted extension, then to a self fitted extension and I'm syncing at ~7000 with a SNR of -1-5db.

[Rik]

The only thing I can think of, then, is that the older wiring is of lower impedance than the new - but that seems a huge difference for such a short run. Is it the proper CW1308 cable you're using?

[Adam]

The only thing I can think of, then, is that the older wiring is of lower impedance than the new - but that seems a huge difference for such a short run. Is it the proper CW1308 cable you're using?

While the packaging doesn't state it is CW1308 cabling it is identical to the CW1308 cabling I purchased from Maplin, the only difference being it is aluminium. Though the existing cabling doesn't look to be copper either.

[Rik]

The pairs are twisted, I take it?