CWNA: Certified Wireless Network Administrator v109 — Question 7

When using a spectrum analyzer to look for non-Wi-Fi interference sources, you notice significant interference across the entire 2.4 GHz band (not on a few select frequencies) within the desktop area of a user's workspace, but the interference disappears quickly after just 2 meters. What is the most likely cause of this interference?

Answer options

• A. USB 3 devices in the user's work area
• B. Excess RF energy from a nearby AP
• C. Unintentional radiation from the PC power supply
• D. Bluetooth devices in the user's work area

Correct answer: A

Explanation

The correct answer is A, as USB 3 devices are known to generate interference in the 2.4 GHz band, particularly when they are in close proximity. Options B and D are less likely because their interference would not typically diminish so quickly with distance, and option C is not the primary cause since PC power supplies generally do not radiate at such high levels in the 2.4 GHz range.