my laptop i have installed BT4 final and Windows 7 in dual boot mode

i have lot of wireless AP's around me, with windows 7 i dont have any issues, i get full signal and the connection is stable

with backtrack,, the connection is not stable, it disconnects often,
i have to remove the wireless adaptor, plug in again, and reconnect to AP
it happens like every 5min
im using AlfaAWUS036H wifi card
backtrack it does automatically detected the drivers

any idea how to solve this issue?