A method for detecting the WiFi signal strength of apple OS X Lion system

This tool is called "wi-fi Diagnostics, but the location is very deep. You need to press the shortcut key command+shift+g in the Finder, and then enter the path/system/library/coreservices/, in which you can find the "wi-fi Diagnostics tool in the folder.

Double-click to run the Wi-Fi Diagnostics tool, select the first "monitor performance" in the window, and the next step appears as shown in this article, where the yellow lines represent the signal strength and the green lines represent the noise. The higher the position of the Yellow Line (the lower the negative), the better the signal, and the lower the Green Line is, the lower the noise (good).

So, if you find that the Yellow line is in a very high position and the Green Line is in a low position, then it is good to prove that your router is not in the wrong place. If not, then you can try to adjust the location of the router, the curve in the diagram will change in real time, very convenient.