i have two wifi cards based on atheros from tp-link wn551g in my computer. First one in mode sta , which works just great, second one in mode AP. Mode Ap is really a problem for my. I have a 2dB anthena in that card i am 2 meters from computer and network is unreliable. It works on 54Mb but ping is really slow , every 3th ping is out of time, data transfer is almost impossible. I have tried downgrade speed to 11Mb without sucess, i have tried all different channels without success. I have even tried it in mode adhoc without succes. The problem is not in card becouse from windows xp it works perfect. I am out of my ideas.\
Please try to help me.