WiFi Radar is a free utility that displays nearby WiFi networks. One of the big benefits of WiFi Radar is that often locates WiFi networks that the default AirPort scanner will ignore.
Grab a copy of WiFi Radar from the AirGrab home page, and install it by opening the .dmg file and dragging it to your Applications folder. Once installed, launch it from there.
The first screen you’ll see is a “nag” window. Just click Continue to begin using it. If you want to avoid this nag/reminder in the future, click the Register button and register your copy for free.
WiFi Radar will quickly scan for available wireless networks. As indicated by the screenshot below, it found 3 in my neighborhood. Leafs is my network (the one I’m using right now in fact). The other two belong to my neighbors across the street. You’ll note that the others have a fairly weak signal strength. Regardless, I’m able to connect to and use both.
At the same time, the default AirPort scanner doesn’t “see” either of the other networks.
This tool is quite helpful when you’re away from home and looking for wireless networks to use. Though you can’t use it to directly connect to a network, you can find out the network name, and then use the normal AirPort utility to manually connect to that network.