How can I use my Mac to determine the optimal WiFi channel to use with my wireless router?

Question

I'm setting up a new router and want to manually select the best channel, how can I run a scan of the networks around me to figure out which channel will have the best performance?

Answer 1

You can easily determine the best channels to use in the native Wireless Diagnostics scanner:

1. Open the "Wireless Diagnostics" Application
2. Ignore the prompts and open "Window", "Scan" in the menu bar
3. Press "Scan Now"

The recommended channel(s) for both 2.4 GHz and 5 GHz will now be present in the Summary pane.

More info on OSXDaily.

Answer 2

Don’t.

There are many apps that you can use from the built in Network Diagnostics to commercial grade WiFi mapping and analyzers. Trying to find which channel to use is pointless nowadays. Unless you’re using a 10+ year old WiFi router that doesn’t handle automatic channel switching well, there’s no need to do this.

Modern WAPs (wireless access point) auto select the best channel for you based on existing traffic and this can change continually given the explosion of wireless devices which we are using every day. Bluetooth devices, wireless peripherals, our phones and devices are all crowding the airwaves. So, what you “capture” today and determine what’s the best channel now might change the next day or even later that afternoon!

The problem with selecting your own channel is that the WAP won’t automatically switch to another when the one it’s manually configured to use becomes saturated with traffic. Yes, you can actually make the problem worse!

Let your WAP (aka your “router”) handle the channel selection. If yo’re in a situation where there’s just too much traffic, it’s better to put a second WAP (Like a WiFi extender) closer to where you use your devices.