Even if you have an enterprise-level Wi-Fi spectrum analyser, like Wi-Spy or AirMagnet, free Wi-Fi tools can also come in handy. You might use them during the planning or installation stages of your wireless LAN, while troubleshooting, or when performing maintenance. They could even serve as your primarily tools in smaller and less-complex environments.
Here are several free programs you can use to do Wi-Fi stumbling and surveying on all the popular platforms — Windows, Mac OS X, and Linux. You’ll be able see all the nearby wireless access points (APs) and their details, including channels, signal levels, and MAC address.