For about the last month I have a similar problem. My wireless, when it connects, stays connected for about 15-20 minutes and then disconnects. The password that then shows up in the network manager is a 64 digit password. I have no idea where it has come from. My password for the router/wlan is only 16 digits.
If I play around long enough I may, or used to be able to, get it to connect again, normally after a new boot. Then again the same problem after 15-20 minutes.
At this point I just look for a cable.
F9 had been my best wireless experience until this complication. Yes, sad to say but windows still connects without problems with the router/wlan.
I suspect a Fedora update has changed something for the worse but with my limited experience I do not know where to look. The notebook is an Fujitzu Siemens Amilio Xi 2550 running with Fedora 9. Here is my iwconfig:
[root@localhost ~]# iwconfig
lo no wireless extensions.
eth0 no wireless extensions.
wmaster0 no wireless extensions.
wlan0 IEEE 802.11abgn ESSID:""
Mode:Managed Frequency:2.437 GHz Access Point: Not-Associated
Bit Rate:54 Mb/s Tx-Power=15 dBm
Retry min limit:7 RTS thr

ff Fragment thr=2352 B
Encryption key

ff
Link Quality=100/100 Signal level:-45 dBm Noise level=-95 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0
pan0 no wireless extensions.
The face symbol should be a colon????
Up until this last month this notebook had worked perfectly. Too many Hotspots, Airports, no idea.
I'd be very grateful for any tips.
Namaste,
Kevin Tough