The coloration in the Amplitude graph shows how often the spectrum is being used. The more intense the color, the more often devices are talking.
Remember that only one wireless device can use a channel at a time, so high utilization means that WiFi devices won’t get a chance to talk.
|Blue||Less than 10 percent||A very short signal, like a clap|
|Red||More than 50 percent||Constant activity, like an air horn|