Wireless Detector is an Android application that displays the strength of mobile phones and WiFi in real time. If the communication in the building is unstable, you can search for places with strong or weak radio waves and radio wave routes.

You can also use the voice function to notify the reception status of radio waves with a beep sound.
If the radio wave is strong, you will be notified in high-pitched sound, and if the radio wave is weak, you will be notified in low-pitched sound, so you can search for radio waves by beep.

Japanese version(電波探知機) 
Spanish version(detector de radio)