Do you want to know what are the active WiFi networks around you, together with the detail of their signal strength, maximum bandwidth, and connection security setting? Do you want to search for WiFi networks with open security?
If you encounter connection and/or bandwidth problem with your own WiFi, do you want to know which is the best available wireless channel to have least disruption from other wireless networks around you?
inSSIDer is a free open source tools for PC running on Windows or Linux to scan for all nearby wireless networks and to troubleshoot competing access points. It is best used in a laptop with WiFi capability. It provides detail of the wireless network around you as shown below.
With it, you can look for unoccupied WiFi channel to set for your own WiFi network, in order not to compete with the others. If you compete the same channel with other access points, you will possibly encounter poor wireless speeds and even frequent WiFi network disconnection.
If you have an Android device (eg. smartphone or tablet), there is a similar tool for the mobile device called WiFi Analyzer. WiFi Analyzer even has a Channel Rating feature to suggest for least competed channel to get the optimum WiFi stability and speed.
If you install the open source WiFi Connecter Library together with WiFi Analyzer, you add in the ability for WiFi Analyzer to connect to the WiFi network that you tap on its listing. This will make WiFi Analyzer to be a nice GUI tool for you to pick for the WiFi network you want to connect.