Really directional bluetooth in powerbooks?

When using my bluetooth headset, if I turn in my chair so the headset is no longer facing the computer, the headset looses the signal completely. However, if I move to the other side of the room (maybe 10 feet away) as along as the headset faces the computer I will have near perfect clarity. So what gives? Is something wrong with my powerbook or is the bluetooth just very directional? Is that even possible?
The headset works fine with anther laptop I have (not a mac). The signal is strong no matter where I am or what direction I am facing.

Thanks for any advice!