Practice Test Geeks(CWT) Certified Wireless Technician Practice Test
← All CWT Flashcard Decks

Wireless Standards & Radio Frequency Fundamentals Flashcards

7 cards from real CWT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Wireless Standards & Radio Frequency Fundamentals flashcards as text

  1. What is the key difference between 2.4 GHz and 5 GHz Wi-Fi in terms of propagation?

    Answer: 2.4 GHz has longer range but is more prone to interference from overlapping channels

    The 2.4 GHz band provides longer range and better wall penetration but suffers from heavy interference due to only 3 non-overlapping channels and many competing devices.

  2. In OFDM, what is the role of subcarriers?

    Answer: They carry independent data streams in parallel across narrow sub-channels within a wide channel

    OFDM divides a wide channel into many narrow orthogonal subcarriers that carry data in parallel, improving spectral efficiency and robustness against multipath interference.

  3. What is the Hidden Node Problem in Wi-Fi, and which mechanism was designed to address it?

    Answer: Two clients can hear the AP but not each other, causing collisions; addressed by RTS/CTS

    The hidden node problem occurs when two clients cannot hear each other but both transmit to the AP simultaneously; RTS/CTS (Request to Send / Clear to Send) exchanges reserve the medium to prevent collisions.

  4. Which 802.11 amendment introduced support for operation in the TV White Space (TVWS) spectrum below 1 GHz?

    Answer: 802.11af

    IEEE 802.11af (also called White-Fi or Super Wi-Fi) operates in unused TV broadcast channels (54–790 MHz), offering extended range due to favorable propagation at lower frequencies.

  5. What is the significance of the Fresnel zone in wireless link design?

    Answer: It is an elliptical region around the line-of-sight path that must be kept mostly clear of obstructions to avoid signal loss

    The Fresnel zone is a series of ellipsoidal regions around the LOS path; obstructions within the first Fresnel zone cause significant diffraction loss, so at least 60% clearance is recommended.

  6. BSS Coloring, introduced in 802.11ax, primarily helps with which issue?

    Answer: Reducing co-channel interference in dense deployments by allowing concurrent transmissions from different BSSs

    BSS Coloring adds a color identifier to frames so devices can distinguish between their own BSS and neighboring BSSs, allowing them to ignore foreign BSS transmissions and reduce unnecessary deferrals.

  7. What does a link budget calculation determine in wireless network planning?

    Answer: Whether the received signal at the far end will exceed the receiver's sensitivity after accounting for all gains and losses

    A link budget sums all gains (transmit power, antenna gain) and losses (path loss, cable loss, fade margin) to verify that received signal power exceeds the minimum receiver sensitivity threshold.