Just click on WiFi button that is located on your taskbar, however this will only scan available wireless networks and provide basic information.
If you require more information such as wireless channel, PHY Types, station MAC address's than WirelessNetView is perfect utility for you. This is very light , portable utility that will also provide you with signal strength ( last and average signal strength ) for each network and detection count. You will be able to see if network is secured, what encryption, RSSI channel frequency, channel number and maximum speed.
I personally use this tool for long time already to check my WiFi coverage. Also it helps me out to avoid interference with other networks. Simply scan for WiFi connections and see what channel they use, than find free channel for your home network. Leave WiFi scanner opened for a while and based on detection counts, last and average signal you will be able to tell if yourWiFi signal is having issues.
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