This mode allows you to monitor specific frequency bands. For example, in a cell-phone free area, this feature can be used to monitor the frequency bands used by cell phones for the purpose of detecting prohibited transmissions.
Monitored Bands mode is similar to Monitored Frequencies mode — the main difference being rather than monitoring individual frequencies, the user assigns a frequency range (i.e. band) to monitor (by specifying ‘Start’ and ‘Stop’ frequencies). This mode displays the RF signal strength that is detected at specific bands defined by the user. The user is alerted with a vertical, red line when the RF energy detected at one of those band exceeds a threshold (here called the Alert Threshold). If the signal strength of an interfering transmitter were to rise above the Alert Threshold (specified by the user) then the corresponding bar for that band turns red (otherwise it appears green). The Alert Threshold is adjusted using the vertical, yellow line that runs from the top-to-bottom of the ‘dBm’ column.
The purpose of the Monitoried Bands chart is to provide a way to alert you in the event the ambient RF energy, measured at specific bands, were to rise above a threshold value — thereby posing a risk to using a specific band as a communication channel, or for detecting prohibited transmissions (as mentioned above). Also, if you wished to monitor RF signals at specific bands then this mode can be used to verify they are currently operating.