A free program for Android, by NeoFrontier Technologies.

Wi-Fi Signal Strength Meter is a utility that can be used to check the strength of wireless internet connections. The application displays the signal strength in decibel-milliwatts (dBm). The application is designed for Android devices and works on most versions, including phones and tablets.

It is used to check the signal strength of Wi-Fi networks. It will also display all the signal strengths of all the available Wi-Fi access points in your vicinity. 

The application can be used to find out the best signal in your home or office, and can be used to check the quality of a Wi-Fi network. It can also be used to discover the frequency and the MAC address of an access point.