I just installed a realtek 8581 wlan card in my pc, running ubuntu gutsy, and can't get a wireless signal. I can, however, get a wireless signal with my laptop at the same exact spot. I even connected a 7dBi antenna to the card, and still network-manager can't find a wireless network. I've even replaced network-manager with wicd, and wifi-radar, and still can't get a signal. I've tried using both the linux native driver and ndiswrapper. Might there be something wrong software wise? It makes no sense to me.

Any help would be greatly appreciated,
--Nate

Post the output of ifconfig & iwconfig. Those will tell us more about what's going on.

Stick it in a different slot.

Its wierd, now that i just checked, ifconfig shows no wlan0, but iwconfig shows wlan0 as

802.11b/g Mode:Manager Frequency=2.412 GHz
Access Point: Not-Associated Bit Rate: 11Mb/s
Retryn Fragment thrff
Power Managementff
Link Quality:0 Everything else is 0

I'll try a different slot.

Ok changed slots and got feedback from ifconfig

wlan0 Link encap:Ethernet HWaddr: 00:0E:2E:EE:A7:5F (Is it safe to post a MAC address?)
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX Packets:0 errors:0 dropped:0 overruns:0 Frame:0
TX packets:58 errors:0 dropped:0 overruns: 0 carrier:0
collisions:0 txqueuelen:1000
RX Bytes:0 (0.0 b) TX Bytes:2436 (2.3 KB)
Interrupt:5 Memory:f89a8000-f89a8100

Yes, it's safe to post a MAC address considering you broadcast it in every frame regardless of any encryption used.

iwconfig is showing the card as not associated. Try setting the mode and the SSID with iwconfig, then pull an IP address.