Is there any interference in your area? What I mean is, is there perhaps other 2.4GHz signals on that is using the same Channel?
Just FYI... but I doubt this would be the cause. I know wireless land phones that operate on 2.4GHz can easily interfere... mine does, have to just about always hit the channel change button once when I turn it on, otherwise it messes up my wifi.
I'm not sure on OS X but I believe there is some form of Stumbler program that can view what wifi are up in your vicinity. I know on PC its called Net Stumbler. (Sorry as I'm rather new to OS X, but I recall seeing it in the past.)
Oh curiousity question, which type of wireless network are you connecting to? G, B, N?
But yeah, as DocSmity said, it might be a firmware issue.