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seems like the known Airport/KP issues after the new updates. as others have said, your only choice would be to re-roll the Atheros drivers to the previous version or buy a Airport Extreme (which works flawlessly).

I had a netgear wireless router that worked ok with my powerbook 12", but when I got my MPB SR and was setting up a new MB for my mom, those 2 new machines (both with N wireless cards) were not happy. I bought an AP Extreme which I was planning on doing anyway and everything is great. FYI: I haven't installed any of the AP updates after seeing so many complaints here.

One thing to look into regarding loss of signal is microwave use. I haven't tested my new APX setup, but the connection with my netgear would grind to a halt when I turned on the microwave. If you are in an apartment building perhaps that is an issue to look into.
 
I had a netgear wireless router that worked ok with my powerbook 12", but when I got my MPB SR and was setting up a new MB for my mom, those 2 new machines (both with N wireless cards) were not happy. I bought an AP Extreme which I was planning on doing anyway and everything is great. FYI: I haven't installed any of the AP updates after seeing so many complaints here.

One thing to look into regarding loss of signal is microwave use. I haven't tested my new APX setup, but the connection with my netgear would grind to a halt when I turned on the microwave. If you are in an apartment building perhaps that is an issue to look into.

glad to see everything is working well for you. but not everyone has the option to just buy an Airport Extreme just to get one computer to get on the internet. so to the OP, you easiest bet would be to backup all the data on the current machine and reinstall the factory OS X. update everything except the Airport driver.

and for anyone whos wondering, I'm still running OS X 10.4.9 (factory version). everything works flawlessly, so really no point for me to update. if its not broken, dont fix it.
 
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