How to find which WiFi frequencies are being used the most near by?

You can get detailed information about a wireless interface by using the iwlist command.

Run the below command from the command line, just copy and paste:

sudo iwlist wlan0 scan | grep Frequency | sort | uniq -c | sort -n

And you will get a result like this:

  2                     Frequency:2.412 GHz (Channel 1)
  2                     Frequency:2.417 GHz (Channel 2)
  2                     Frequency:2.462 GHz (Channel 11)
 10                     Frequency:2.437 GHz (Channel 6)

As an extra bit of useful data, you can see what frequencies your wifi card supports using this command:

iwlist wlan0 channel

use this is good , will give you all info about mac , channel and power signal

Linssid

Install wifi-radar from the repositories. It will show you what channel each network is using.

https://apps.ubuntu.com/cat/applications/precise/wifi-radar/