said by kukur 
:I am starting to wonder if the AP's antenna has moved enough to create a geographical problem in that area. Perhaps this area is on the very fringe of the sector antenna's signal and although showing a good signal, isn't able to remain stable.
TIA
I would venture to say that your AP or AP's antenna and or cable is having a problem. I would bet that your other clients have dropped somewhat as well but maybe they are closer so it doesn't effect them as much. (graphing has helped me here)
