Spectrum Analysis

This feature provides visual spectrum analysis capabilities that scan radios for RF channel conditions and sources of interference which can potentially impact WLAN efficiency. Based on the spectrum analysis data, corrective measures such as determining optimal channel planning, debugging client related connectivity issues and automatic transmit power settings are initiated. This facilitates quality wireless service levels by ensuring the optimal usage of the channels considering the information provided by the FortiLAN Cloud spectrum analyser. Both 802.11 and non-802.11 sources of interference can be detected and analyzed by the spectrum analyzer.

Notes:

• Spectrum analysis is only supported when the radio is in the monitor mode.
• FortiAP supports spectrum analysis and is online.
• FortiAP Advanced Management License is required.

Select the channels to be scanned and configure the scan duration, the spectrum analysis is performed on both 2.4 GHz and 5 GHz frequency bands. The spectrum analyzer result displays widgets with the type of interference, signal strength, impacted channels, and wireless spectrum current utilization, start and end time and duration of the interference. It classifies wireless & non-wireless interferences to easy identification of the source.

• You can select the AP, Radio, and Channels to be scanned for interferences.
• The Scan Duration can be set to 1, 5, 10, or 15 minutes.
• The Sampling Interval and the number of Spectrogram Samples cannot be modified.

Select Start and the GUI periodically polls the spectrum analysis data based on the fixed sampling interval of 1000 milliseconds. Data is visualized as 4 charts representing signal interference marking the noise levels for each channel, signal interference spectrogram representing 60 samples for different channels at specific time intervals, the duty cycle charts marking the extent to which a non-WiFi device/neighbouring AP is interfering, and the duty cycle spectrogram representing 60 such duty samples for each channel over a period of time.

The tabular data for non-WiFi interference displays the time and frequency of last detection and any of the following type of devices causing the interference.

• Microwave ovens
• Video bridges
• Wi-Fi, DSSS cordless phones
• Bluetooth, FHSS cordless phones

The tabular data for WiFi interference displays the online neighbouring AP's BSSID, SSID, maximum signal strength, and channel and time of last detection.