CWS CWS Basic RF Principles 2

Question 1

A wireless signal at 5 GHz has approximately what wavelength in free space?

Accepted Answer

6 cm

Answer

Wavelength = speed of light / frequency; 3×10^8 / 5×10^9 ≈ 0.06 m (6 cm).

Question 2

Which RF propagation phenomenon occurs when a signal bends around the edge of an obstacle?

Accepted Answer

Diffraction

Answer

Diffraction is the bending of RF waves around edges or corners of obstacles.

Question 3

Converting 100 mW to dBm gives which value?

Accepted Answer

20 dBm

Answer

dBm = 10 × log10(100 mW / 1 mW) = 10 × log10(100) = 10 × 2 = 20 dBm.

Question 4

What effect does increasing channel width from 20 MHz to 40 MHz have on throughput and noise?

Accepted Answer

Higher throughput and higher noise floor

Answer

Doubling channel width doubles data capacity but also captures more ambient noise, raising the noise floor by ~3 dB.

Question 5

In RF terminology, what does EIRP stand for?

Accepted Answer

Effective Isotropic Radiated Power

Answer

EIRP is Effective Isotropic Radiated Power, representing the total power an antenna would emit if it radiated equally in all directions.

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