That doesn't sound good, which driver are you using with it and do you use the supplied 2.5dbi antenna or some other one?
How far away from the AP are you sitting when this happens and do you have a clear line of sight? Personally I have to say that I have not noticed any issues of the kind you are describing with my AWUS036H. I use the supplied 2.5dbi antenna + an self made parabolic reflector.


