Practice Test Geeks(CWS) Certified Wireless Specialist Practice Test
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RF Behavior & Signal Propagation Flashcards

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

Read the first 7 RF Behavior & Signal Propagation flashcards as text

  1. What term describes the process by which an RF signal bounces off a flat, smooth surface such as a metal wall?

    Answer: Reflection

    Reflection occurs when an RF wave strikes a smooth, flat surface and bounces back at an angle equal to the angle of incidence.

  2. Which material is known to cause the highest RF signal absorption losses in an indoor environment?

    Answer: Cinder block walls

    Cinder block (concrete masonry) walls cause high RF attenuation, often 10–15 dB or more, making them one of the most significant indoor obstacles.

  3. In a point-to-multipoint outdoor wireless deployment, what is the primary propagation concern over long distances that causes signal bending toward the Earth?

    Answer: Atmospheric refraction due to the k-factor

    The k-factor describes how the Earth's atmosphere refracts RF signals, effectively making the Earth appear larger and affecting line-of-sight clearance calculations.

  4. Which antenna property describes the ratio of power radiated in a specific direction versus an isotropic radiator?

    Answer: Antenna gain (dBi)

    Antenna gain in dBi expresses how much more signal an antenna radiates in its primary direction compared to a theoretical isotropic radiator.

  5. What propagation effect occurs when atmospheric conditions create a layer that traps RF energy close to the Earth's surface, extending range unexpectedly?

    Answer: Tropospheric ducting

    Tropospheric ducting traps RF signals in a low-altitude layer, allowing them to travel far beyond their normal range and potentially causing interference.

  6. A wireless engineer measures the received signal level at -70 dBm. The noise floor is -95 dBm. What is the SNR?

    Answer: 25 dB

    SNR is calculated by subtracting the noise floor from the signal level: -70 dBm - (-95 dBm) = 25 dB.

  7. Which 802.11 MIMO technique uses multiple antennas to transmit identical data simultaneously, improving signal reliability rather than throughput?

    Answer: STBC (Space-Time Block Coding)

    STBC transmits redundant copies of data across multiple antennas in a space-time coded pattern, improving reception reliability without increasing data rate.