Express issues.

I have a fairly new (1 month) old Airport Express. Until recently the signal strength has usually been at its max, especially given that I am less than two feet from the router 90% of the time. Yesterday it started giving me serious trouble. I sometimes get as low as 4/15 bars. Not getting full two feet from the router is utterly ridiculous, but getting 4/15 makes this thing essentially completely useless for its intended purpose, given that if I moved 10 feet away it would basically give me nothing. Any suggestions, or should I just take this back to Apple?

Are you sure there's not interference somewhere?

Make sure it's not anywhere near cordless phones, microwaves, or any other wireless device.

Secondly, try changing the channel that the Airport Express is operating on and see if that helps.

Any interference would have to be completely new and unexpected, because I actually made it a point to unplug my cordless phone and I double checked to make sure my wireless mouse (which is 27 MHz anyway) wasn't interfering. The microwave has been off this entire time, too. Channel was on automatic before, and I tried switching it to 7. It stayed at full power for about two minutes before it went back down again, and jumped around a bit. It's currently at full, and for the moment it seems to be staying that way. I guess I'll see how long it lasts. I did, however, also lower the multicast rate from 11 to 5.5, and turned OFF interference robustness on the router (it helped zilch before, enabled or disabled on the AE card.)

Radio Frequency interference can come from anywhere. unless you live on a farm in the middle of nowhere, i would say that there is interference. i recently had this problem with my ibook and linksys router. i changed the channel and it is fine now.

Maybe your neighbor is Alexander Graham Bell.