Ham Radio Technician Test Radio Wave Propagation & Modulation 4

Question 1

What is the approximate height of the F2 ionospheric layer above Earth's surface?

Accepted Answer

200–400 km

Answer

The F2 layer exists at roughly 200–400 km altitude and is the primary layer responsible for long-distance HF sky wave propagation.

Question 2

What causes 'flutter' in signals received via auroral propagation?

Accepted Answer

The rapid movement and structure of the aurora causing continuously shifting reflection points

Answer

Aurora-reflected signals exhibit a characteristic flutter or warbling sound because the aurora curtain is constantly moving and the ionized region varies rapidly.

Question 3

Which type of modulation encodes information by varying the frequency of the carrier wave?

Accepted Answer

Frequency modulation (FM)

Answer

Frequency modulation (FM) varies the carrier frequency in proportion to the instantaneous amplitude of the modulating audio signal.

Question 4

Why is the 10-meter band generally considered a daytime band during low solar activity?

Accepted Answer

Without adequate F2 ionization, signals are not refracted back to Earth and pass into space

Answer

During low solar activity, the F2 layer may not be ionized enough to refract 10-meter signals back to Earth, especially at night when solar ionization stops.

Question 5

What is the relationship between frequency and wavelength for radio waves?

Accepted Answer

They are inversely proportional — higher frequency means shorter wavelength

Answer

Wavelength equals the speed of light divided by frequency; as frequency increases, wavelength decreases proportionally.

Ham Radio Technician Test Practice Test

Ham Radio Technician Test Practice Test

Ham Radio Technician Test Radio Wave Propagation & Modulation 4