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
Which term describes the gain of an antenna compared to an isotropic radiator, expressed in dBi?
Answer: Antenna gain referenced to isotropic
dBi expresses antenna gain relative to a theoretical isotropic radiator that radiates equally in all directions.
A higher-order modulation scheme like 256-QAM compared to 64-QAM requires:
Answer: A higher SNR to decode reliably
256-QAM encodes more bits per symbol but requires a cleaner, higher-SNR signal to distinguish the denser constellation points.
What phenomenon occurs when an RF wave passes through the boundary between two media (e.g., air to glass) and changes direction?
Answer: Refraction
Refraction is the bending of an RF wave as it passes from one medium into another with a different refractive index.
What does the term 'noise floor' represent in an RF system?
Answer: The minimum detectable signal level limited by thermal noise and receiver sensitivity
The noise floor is the level of background noise below which signals cannot be reliably detected by the receiver.
MIMO technology improves wireless throughput primarily by:
Answer: Transmitting multiple independent data streams simultaneously using multiple antennas
MIMO uses multiple transmit and receive antennas to send parallel spatial streams, multiplying throughput without additional spectrum.
Which factor does NOT directly affect free-space path loss?
Answer: Transmit power
Free-space path loss depends only on distance and frequency (wavelength); transmit power is a link budget input, not part of FSPL itself.
When using a directional antenna, narrowing the beamwidth results in:
Answer: Higher gain in the main lobe direction
Narrower beamwidth concentrates more energy in a specific direction, increasing the antenna's gain in that direction.