It’s been a Problem since i upgraded my good old 12inch Powerbook G4 from Tiger to Leopard:

WiFi Connection drops when moving more than 1 metre away from the Router.

There are various Websites and Forum Threads describing the same Problem, mostly when updating the OSX Install (not doing a Clean Install). I tried nearly all from removing the Airport Startup Preferences Plist File, changing Channels, turning of IPv6 Support, disabling DNS and so on. Latest try was changing the Encryption from WEP to WPA: Still no WiFi Connection when the Powerbook is more than something like 2 metres away from the Router.

Guess my last try will be doing a clean Install, after i backuped all my Data… Thanks Apple for nearly no Support on this Thread.