Upload noise margin always > than download?

[DesertRaven]

Any idea why the upload noise margin always seems to be higher than the download margin – I thought the modem was always aiming for the default of 6.9 db, or does that only apply to download?

Thanks

[dholdi]

I thought the modem was always aiming for the default of 6.9 db, or does that only apply to download?

Yep, the upload will always be different.

[Isitme]

It looks like you have not been upgraded yet. When you are the upload speed increases and the noise margin comes nearer the default. Post your stats if you would like advice.

[DesertRaven]

A quick bit of background to the stats, I’m running V1.03.87 (CU3.04) - thank’s IsItMe (your suggestion) it’s a fantastic firmware update for the DG834GT, I’ve lowered my default Noise Margin to 3.9, and also use G.DMT which is overriding the default DSLAM ADSL2+ preference.

Don’t panic, all is well as I’ve a very stable line and it’s been running without any issues since the firmware update over a week ago!
Down Up
SNR (dB): 4.9 12.0
Attn(dB): 54.0 31.5
Pwr(dBm): 19.5 12.5
Max(Kbps): 4672 1056
Rate (Kbps): 4096 800

From the stats I’m pushing things with my download speed vs margin however the upstream margin ‘suggests’ the cap could be raised slightly.

It’s interesting looking at the Max (Kbps) , I’m guessing this is calculated by the DSLAM during DLM and it’s this figure Sky use on MySky when they say “your line is estimated capable of 4.5Mbps”. From the Up Max (Kbps) I’d estimate I could get about 900 Kbps given my noise margin.

It’s more out of interest than anything.

(Stats are from a Master Socket Splitter, no change if in Test Socket).

[Isitme]

Be careful about lowering your noise margin too much. If it is too low, although you have a better sync and may not drop, excessive errors can slow your actual download speed. If DLM has not run on your line, I would advise you to leave any tweaking until it does so.