Ham Radio Technician Test Radio Wave Propagation & Modulation 2

Question 1

What effect does a temperature inversion in the atmosphere have on VHF radio waves?

Accepted Answer

It can cause signals to travel much farther than normal

Answer

Temperature inversions can trap VHF signals near the Earth's surface, allowing them to travel far beyond the normal line-of-sight distance through ducting.

Question 2

Which modulation mode is most commonly used for FM voice transmissions on VHF/UHF amateur bands?

Accepted Answer

Frequency modulation (FM)

Answer

FM is the standard mode for local VHF/UHF voice repeater operation because it provides good audio quality and rejects noise effectively.

Question 3

What is the term for the lowest frequency that will be refracted back to Earth from the ionosphere at vertical incidence?

Accepted Answer

Critical frequency

Answer

The critical frequency is the highest frequency that is refracted back to Earth when a signal is transmitted straight up (vertical incidence).

Question 4

Which ionospheric layer is primarily responsible for long-distance HF communication during daytime?

Accepted Answer

F2 layer

Answer

The F2 layer, found at 200–400 km altitude, is the most important layer for long-distance HF propagation because it persists day and night.

Question 5

What type of propagation allows a 10-meter signal to be received across the country with very low power during high solar activity?

Accepted Answer

F2 ionospheric propagation

Answer

During periods of high solar activity, F2 layer ionization is strong enough to refract 10-meter signals back to Earth over very long distances.

Ham Radio Technician Test Practice Test

Ham Radio Technician Test Practice Test

Ham Radio Technician Test Radio Wave Propagation & Modulation 2