Wifi on Ubuntu less powerful than on XP, WTF ?

[Vincent Arnoux]

Hello,
I installed Ubuntu Breezy on my centrino laptop (IPW2200).
I connect to the internet through another PC with a Belkin wifi board
(running XP ) with an Ad-hoc connection.
What I see from experience is that when booted on XP, I can put my
laptop almost anywhere in the house. But when running Ubuntu, I need to
come MUCH closer of the gateway PC (no more than 6 meters).
The signal power looks to be the same, but I keep getting disconnect
with Ubuntu... Does anyone know how to fix this ?

Vincent