In F16, Atheros AR5008 being restricted to 18mb/s

[JD]

$ iwconfig wlan0
wlan0     IEEE 802.11bgn  ESSID:"Private"
           Mode:Managed  Frequency:2.452 GHz  Access Point: 
00:AA:BB:CC:DD:EE
           Bit Rate=18 Mb/s   Tx-Power=27 dBm
           Retry  long limit:7   RTS thr=2346 B   Fragment thr=2346 B
           Power Management:off
           Link Quality=58/70  Signal level=-52 dBm
           Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
           Tx excessive retries:0  Invalid misc:32   Missed beacon:0

I have tried to force 54G, to no avail:

# iwconfig wlan0 rate 54G
# iwconfig wlan0
wlan0     IEEE 802.11bgn  ESSID:"Sean&Anna"
           Mode:Managed  Frequency:2.452 GHz  Access Point: 
00:1D:5A:C8:91:C1
           Bit Rate=18 Mb/s   Tx-Power=27 dBm
           Retry  long limit:7   RTS thr=2346 B   Fragment thr=2346 B
           Encryption key:off <<<---- Not true!! Do not know why 
iwconfig is saying this.
           Power Management:off
           Link Quality=57/70  Signal level=-53 dBm
           Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
           Tx excessive retries:0  Invalid misc:62   Missed beacon:0

Is the router capable of limiting the rate selectively for some wifi clients
and not others? I have checked 2 other computers on  wifi, and they
are at 54G.