We can rejoice in the number of Wi-Fi apps available to help us, and one of the best and highest rated is WiFi Explorer. Wireless tools such as WiFi Explorer have a lengthy list of features, but it’s the basics you’re after. A strong Wi-Fi signal.
In this case, WiFi Explorer supports both 2.4GHz and 5GHz frequency bands (if your Mac does), and channels ranging from 20, 40, 80, and 160MHz. More importantly, WiFi Explorer works will all the popular IEEE network standards, 802.11a/b/g/n/ac.
Your entire nearby wireless network coverage is listed and graphed by signal strength.
It isn’t just a matter of listed network connected devices. WiFi Explorer also details signal strength, channels and channel conflicts, and signal to noise ratio. If your WiFi doesn’t seem as fast as you expect, it’s easy to find conflicting devices on the same or nearby channels, which also makes the graphical analysis of your network a worthy feature.
WiFi Explorer makes it easy to convert from dBm (the common measurement system for signals) to percentages. Columns are selectable and sortable, and each network can be color customized for easier tracking. Results of a particular scan can be saved later for review.
This is the one I use but you might also like WiFi Scanner which looks and works much the same but has a built-in speed test for each network.