OpenSignal - 3G/4G/WiFi will shows you a graph of close signals. You will be able to see all the mobile phone antennas and WiFi routers on a map. In addition, you will have various maps of the coverage of the networks you have around you for 2G, 3G and 4G (LTE).
Aside from that, OpenSignal - 3G/4G/WiFi will lets you make a speed test for your Android terminal. This way you will be able to quickly check the download and upload speed you have with your data network.
You will be able to easily save all this data in a document, on an SD card or the memory of the device.
OpenSignal - 3G/4G/WiFi is a very simple and easy to use tool that will help you to obtain a lot of useful information about your data network.