Find the best wifi channel for your router
Hold the Option (alt) key and click the Wi-Fi icon on the menu bar at the top of your screen. Select “Open Wireless Diagnostics.”
Ignore the wizard window, and then go to Window menu then select “Scan”
The “Best 2.4 GHz Channels” and “Best 5 GHz Channels” fields will recommend the ideal Wi-Fi channels you should be using on your router.