CWS Basic RF Principles 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 CWS Basic RF Principles flashcards as text
A wireless signal at 5 GHz has approximately what wavelength in free space?
Answer: 6 cm
Wavelength = speed of light / frequency; 3×10^8 / 5×10^9 ≈ 0.06 m (6 cm).
Which RF propagation phenomenon occurs when a signal bends around the edge of an obstacle?
Answer: Diffraction
Diffraction is the bending of RF waves around edges or corners of obstacles.
Converting 100 mW to dBm gives which value?
Answer: 20 dBm
dBm = 10 × log10(100 mW / 1 mW) = 10 × log10(100) = 10 × 2 = 20 dBm.
What effect does increasing channel width from 20 MHz to 40 MHz have on throughput and noise?
Answer: Higher throughput and higher noise floor
Doubling channel width doubles data capacity but also captures more ambient noise, raising the noise floor by ~3 dB.
In RF terminology, what does EIRP stand for?
Answer: Effective Isotropic Radiated Power
EIRP is Effective Isotropic Radiated Power, representing the total power an antenna would emit if it radiated equally in all directions.
Which type of antenna radiates RF energy equally in all directions in the horizontal plane?
Answer: Omnidirectional
Omnidirectional antennas radiate energy equally around 360° in the horizontal plane.
Free-space path loss (FSPL) increases as frequency increases because:
Answer: Higher-frequency signals spread over a larger effective area relative to antenna size
FSPL increases with frequency because a fixed-size antenna captures a smaller fraction of the wavefront as wavelength decreases.