Users Guide

Dell PowerConnect W-Series ArubaOS 6.1 | User Guide Spectrum Analysis | 637
Interference Power
The Interference Power chart displays various power levels of interest, including the Wi-Fi AP with maximum
signal strength, noise, and interferer types with maximum signal strength. The ACI displayed in the Interference
Power Chart is the ACI power level based on the signal strength(s) of the Wi-Fi APs on adjacent channels. A
higher ACI value in Interference Power Chart does not necessarily mean higher interference since the AP that is
contributing to the maximum ACI may or may not be very actively transmitting data to other clients at all times.
The ACI power levels are derived from the signal strength of the beacons.
This chart displays the noise floor of each selected channel in dBm. The noise floor of a channel depends on the
noise figure of the RF components used in the radio, temperature, presence of certain types of interferers or noise,
and the width of the channel. For example, in a clean RF environment, a 20 MHz channel have a noise floor
around -95 dBm and a 40 MHz channel will have a noise floor around -92 dBm. Certain types of fixed-frequency
continuous transmitters such as video bridges, fixed-frequency phones, and wireless cameras typically elevate the
noise floor seen by the spectrum monitor. Other interferers such as frequency-hopping phones, Bluetooth and
Xbox may not affect the noise floor of the radio. A Wi-Fi radio can only reliably decode Wi-Fi signals that are a
certain dB above the noise floor and therefore estimating and understanding the actual noise floor of the radio is
critical to understanding the reliability of the RF environment.
The chart also includes information about the AP on each channel with the highest power level. You can hover
your mouse over an AP on the chart to view the AP’s name, SSID and current power level. The example below
shows that the AP with the maximum power on channel 157 has the SSID qa-ss, and a power level of -55dBm.
Figure 149 Interference Power
Table 138 describes the other optional parameters you can use to customize the interference power chart. Click
the down arrow in the upper right corner of this chart then click the Options menu to access these configuration
Show Select a checkbox to display that information on the FFT Duty Cycle chart.
 Duty Cycle: The percentage of duty cycle the channel or frequency was actively utilized.
 Max Hold: The maximum recorded percentage of active duty cycles for the channel frequency
since the chart was last reset. To clear this setting, click the down arrow at the end of the title
bar for this graph and select Reset MaxHold.
 Max of last sweeps: By default, this chart shows the maximum percentage of active duty cycles
for the channel of frequency recorded during the last 10 sweeps. To change the number of
sweeps used to determine this value, enter a number from 2 to 20, inclusive. To clear this
setting, click the down arrow at the end of the title bar for this graph and select Reset
MaxNSweep.
Table 137 FFT Duty Cycle Options (Continued)
Parameter Description