Wi-Fi Channel Tool (wifichannel)
mini Lab, more of a warm up Lab
WLAN Pi comes with a small CLI tool called wifichannel
This tool began as a simple conversion utility, for switching between channel numbers and centre frequencies.
Channel maths
Query wifichannel with the command
The output gives you information about channel 7
List all channels
Display all 2.4 GHz channels:
Display all 5 GHz channels:
How would you display all 6 GHz channels?
This command will help you if you are ever in doubts:
Note the Lower 6 GHz and Upper 6 GHz channels.
In the FCC regulatory domain, we can use the entire band including the lower and upper 6 GHz channels.
In the ETSI and Ofcom regulatory domains, they can only use the Lower 6 GHz channels.
Filter output with Linux filters (grep)
You can filter the output of most command line utilities to make the output more efficient.
Example
How many channels in the 2.4 GHz band are 'recommended'?
First, run the command to display all 2.4 GHz channels:
You could count the lines manually, but there is no need. Computers can already do that, really fast.
Using a Linux utility called grep we can filter the output to only include lines that match an expression (a particular string or pattern):
Be precise with your search terms (strings), capitalisation matters.
Finally, we can simply count the number of lines returned by the command using word count, that command looks like this:
The wc command has nothing to do with restrooms 😉
It stands for "word count" and the "l" argument stands signifies lines.
Install wifichannel to your laptop
If you would like, you can install wifichannel on your laptop and use it even more often. Here are the instructions.
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