Airport card shows no signal

Question

Airport Express Card in ibook g3 was working perfectly then I took it out to test on an imac g4 then shows no signal on both of thr computer now.
Any suggestions, it picks up all the surrounding wifi signals but when I choose any ones, it says some error. Only difference is the bar shows no signal.

Answer 1

You may to check which channels the different wireless networks are on.
Your network needs to be at least three or more channels away.
So if the neighbour's network is on channel 6, ensure yours is on channel 1 or 11.
Use iStumbler to find which channels the networks are using.
http://www.istumbler.com/
It should be noted that iStumbler won't pick up closed networks.
In normal circumstances, I have my wireless router
SSID set to not broadcast, and it has operated
without any problems like this for a couple of years.
Closing your network can cause this issue, especially if the networks are on the same channel.
Where possible I would avoid closing (not broadcasting your network) if possible. A wireless network is still broadcasting and therefore detectable regardless of whether you broadcast the SSID (closed network) or not.
I have my Network Preferences settings to "join most
recently used available network" and to "remember
password."
Change this to join a specific network (if you are running 10.2), as once your Mac has joined your neighbour's network it will think you always want to join it.
Does this sound like an interference problem to
anyone?
Yes
iFelix