In reply to a post by shaneosborne:

DAY 01 & 02
Broadband Link Downstream Upstream
Connection Speed 4091 kbps 606 kbps
Line Attenuation 23.0 dB 13.6 dB
Noise Margin 15.3 dB 19.19 dB

DAY 03
Broadband Link Downstream Upstream
Connection Speed 7002 kbps 796 kbps
Line Attenuation 23.0 dB 13.6 dB
Noise Margin 14.4 dB 15.15 dB

DAY 04
Broadband Link Downstream Upstream
Connection Speed 10237 kbps 1117 kbps
Line Attenuation 23.0 dB 13.6 dB
Noise Margin 8.6 dB 8.8 dB

DAY 05
Broadband Link Downstream Upstream
Connection Speed 13307 kbps 1110 kbps
Line Attenuation 23.0 dB 13.6 dB
Noise Margin 6.0 dB 8.8 dB

DAY 06
Broadband Link Downstream Upstream
Connection Speed 16378 kbps 1117 kbps
Line Attenuation 23.0 dB 13.6 dB
Noise Margin 6.5 dB 9.9 dB

I'm a little confused and hope someone can ease my confusion.
As you can see by my daily line stats above, my speed as been increasing daily whilst Sky begin working out the best stable speed my line can support.

What's confused me is that I thought as your speed/sync increases it creates more noise which in turn lowers the noise margin, as you can see by the stats this isn't the case. I always thought the faster the line, the more noise it creates. I'm obviously wrong, can someone explain please?

As I believe I said, the way Sky manage the power levels mean that the noise margin does not follow the normal rules.

By reducing the amount of power (i.e. electricity) used they can reduce power consumption in exchange hardware, so run it cooler, save power and maybe reduce cross talk issues a little.

BTW increasing line speed does not create more noise as such, but because you are using more parts of the frequency allocation, there is less margin available between the level of noise present and the transmitted or received signal as.

Ah right! I was aware if what you said but didn't know how it worked differently to others.

So when working out the speed they also adjust the power at the same time when others don't thus when the line reaches a low NM they up the power along with the sync?

Thanks for explaining...

It does seem like a power, noise and margin balancing act: start off on largish sync time margin with reduced power; increase the power and monitor any significant reductions in margin; lower the sync time margin, again with reduced power, then increase the power, and so on...and I guess, each time this will increase sync speeds accordingly until a point of specified potential instability is detected on a particular line?

If that is a simplified view of the system it looks pretty good to me, however, perhaps one has to be patient for the first few days or so

That's how I understood it... Looks good so far, lets hope they can throw a little more power down my line without it causing problems

http://www.coolwebhome.co.uk/calc/calculator.php?par...

Estimates based on latest stats, the key one is the attenuation based estimate which says
"Normal speed range at 23dB attenuation is 17400 Kbps to 19000 Kbps"

So seems scope for a bit more, whether Sky deliver is another matter.

In reply to a post by shaneosborne:

That's how I understood it... Looks good so far, lets hope they can throw a little more power down my line without it causing problems

Hopefully yes, since with a downstream 6dB SNRM a 19Mbps sync speed should be possible on your line - a 3dB margin would probably give you even faster speed but it might be unstable...

Guess you will probably switch to the Billion router once the connection has stabilised at or above your benchmark 16Mbps sync?

I'll switch to the Billion after the 10days, tweak and then plug in my Samknows monitoring router and hopefully all will be fine for then on...

In reply to a post by MrSaffron:

As I believe I said, the way Sky manage the power levels mean that the noise margin does not follow the normal rules.

By reducing the amount of power (i.e. electricity) used they can reduce power consumption in exchange hardware, so run it cooler, save power and maybe reduce cross talk issues a little.

This in fact sounds like "DSM Level 2", the next step up from plain DLM.

The aim is to set the power level on many lines in a way that allows them to co-operate in causing the least amount of noise to each other.

It could be that, while the power level of *this* line is being adjusted upwards, the power level of other lines is being adjusted downwards slightly.

DSM Level 2 is meant to work on frequencies too, adjusting the way in which power is used over different frequencies. It could be that the bits/tone graphs have been altering too.

Well, a little more extra today. now at 18Mbps / 1.2Mbps

Connection Stats;



Broadband Link Downstream Upstream
Connection Speed 17961 kbps 1189 kbps
Line Attenuation 23.0 dB 13.6 dB
Noise Margin 6.1 dB 9.9 dB