Since buying my 15" Alum PowerBook G4 the built in wireless has been weak. Some days I have full strength, other times 1/2 and sometimes so weak it can't connect. While this is going on all systems around the PowerBook work fine. Turning the wireless adapter off & back on magically gives me full signal strength for awhile. I've been forced to use a USB adapter for reliable service. I've opened the system and confirmed none of the antenna wires are pinched at the hinge area and that there are no ovious problems. Looking for suggestions from others where to look or how to imrove coverage.