Line stats help

Having recently moved i have finally got broadband activated this week. At my previous address i always used IDNET but deciding to try and save a bit of money i have gone for Sky unlimited and i am slightly worried about my noise margin, should it be as low as 3? Here are my stats from Thursday

Connection Speed 20796 kbps 1283 kbps
Line Attenuation 16.0 dB 9.8 dB
Noise Margin 6.1 dB 8.8 dB

And here are my stats today
Connection Speed 22007 kbps 1390 kbps
Line Attenuation 16.0 dB 9.8 dB
Noise Margin 3.1 dB 6.6 dB

I have run a few speedtests and vary from around the 16 to 18mbs mark

Oh and maybe i should say i am roughly 186 metres away from my exchange

Sky's DLM will select 3 dB if it thinks you have a good line. It shouldn't be a problem.

A low noise margin is actually a good sign. That's assuming its stable. The noise margin is just a sort of "safety margin" that is set when ADSL session is synced. The lower the margin, the more is available for carrying data. It will only be applied if the line is stable, and 3dB is as low as any ISP will normally set it.

The result is you have the best of all worlds. A stable line running at very close to the theoretical maximum.

nb. 186 metres is very precise. Have you been out with a tape measure?

You should check that your PHONE LINE is actually around that 186 M length.

I recollect one person posting on this site that his parents were about a similar distance from their Exchange; but their PHONE Line was about 1200 Metres long, as their PCP (green/grey Distribution Box) being about 700 M from the Exchange, so 700 M for the E(xchange) side to the PCP; plus 500 M on the D-side to come back to his parents' house.

And even the PCP to house distance in itself, can be misleading.

My PCP is literally "across the road, about 50 M away, with the Exchange cables, Fibres etc going past the corner of my house, about 5 M from the Phone entry point at my front door.

But the PHONE Line Distance from the PCP to my house is about 250 M, from the PCP the line heads a proven 125 M to the east, returning back westerly to my house by another 125 M.

Virtually all of the estate wiring is under-ground, so "not obvious".

There is a small pavement level junction box at the reversal point, which prove to be the source of problems in the early days of dial-up.

And this was a "green-field" estate, pre-wired during construction, there is no obvious reason for that routeing.

I'm sure the line is a lot longer than 186 metres. However, with a 22Mbps sync speed it's going to be in the 100s, not thousands of metres range. I think the posting was about what the implication of the stats was rather than any particular problem.

In reply to a post by lacuna79:

i am roughly 186 metres away from my exchange

Your line length is actually about 1.2 km.

You have an excellent line there and your ISP is running it with a default 3dB NM as it is so stable, so you get even faster speeds.

Agreed.