Source: http://www.macobserver.com/tmo/answers/4...

Alf Watt, former Apple Wi-Fi engineer and creator of the fantastic Wi-Fi utility, iStumbler, joined us on this week's Mac Geek Gab 509 to talk all things Wi-Fi. The episode contains a bunch of juicy Wi-Fi tips and I highly recommend you give it a listen, but for now our four favorite tips are listed below. Think of this as the MGG 509 Cliff's Notes... and make sure you read, erm, listen to the whole thing, too. On to the tips:

1. Use same SSID for all radios on the same network (be they 2.4GHz or 5GHz). If you have onenetwork in your home but have either multiple routers/access points for better coverage or multiple radios in one access point, the advice is the same: use the same SSID (wireless network name) for all of them and let the client devices each decide which is best to use.