A lower attenuation is better.
Regarding the noise margin; if one is syncing at the max, the higher the margin the better. If syncing at less than the max, a lower margin is better.
Your very high d/l noise margin indicates that you have a very poor line. Whether you will be able to do something about it is another matter. My parents have a similar margin to you, except they sync at their max speed - that is a much better line than they will ever need and I am jealous.
As regard higher power. The higher the better up to a point. If you have higer power then everybody will and interference between connection becomes significant past a certain point.
Stress - the condition brought about by having to resist the temptation to beat the living daylights out of someone who richly deserves it.
Edited by DrTeeth (Fri 22-Apr-11 10:53:25)