HAM Radio Extra Class Test Radio Wave Propagation Questions and Answers

Question 1

An amateur radio operator observes that VHF signals are being received from stations over 2,000 km away, with the path crossing the geomagnetic equator.
The signals are strongest in the late afternoon and early evening.
Which propagation mode is responsible for this phenomenon?

Accepted Answer

Transequatorial Propagation (TEP)

Answer

Tropospheric ducting

Answer

Auroral backscatter

Answer

Meteor scatter

Question 2

Which of the following best describes the atmospheric condition that creates a tropospheric duct, enabling long-distance VHF and UHF propagation?

Accepted Answer

A temperature inversion where a layer of warm air is over a layer of cooler air

Answer

A rapid decrease in atmospheric pressure with altitude

Answer

A layer of cool, moist air situated above a layer of warm, dry air

Answer

High levels of D-layer absorption during midday

Question 3

A radio amateur is attempting a long-distance contact on a lower HF band (e.g., 80 meters) and notices a significant signal enhancement for a short period around sunrise and sunset, but only when the path is aligned with the terminator. What is this mode of propagation called?

Accepted Answer

Gray-line propagation

Answer

Sporadic E-skip

Answer

Transequatorial propagation

Answer

Backscatter

Question 4

When a linearly polarized VHF or UHF signal from a satellite passes through the ionosphere, its plane of polarization is rotated. What is this effect called?

Accepted Answer

Faraday rotation

Answer

Doppler shift

Answer

Tropospheric scatter

Answer

Plasma dispersion

Question 5

An operator notices that VHF signals are being reflected from the auroral zone, characterized by rapid, fluttery fading and a distorted, 'watery' sound. Which of the following is a key characteristic of auroral propagation?

Accepted Answer

Narrow-bandwidth modes like CW and digital are most effective due to phase distortion.

Answer

Signals are strongest when antennas are pointed directly at the other station.

Answer

It primarily affects the lower HF bands below 10 MHz.

Answer

The propagation path is stable and lasts for many hours.

Question 6

A ham radio operator is using the WSJT-X software mode MSK144 to make contacts on the 144 MHz band when no other propagation seems to be present. What is the mechanism that allows for these brief communication bursts?

Accepted Answer

Ionization trails left by meteors entering the atmosphere

Answer

Reflection from high-altitude aircraft

Answer

Backscatter from the F-region of the ionosphere

Answer

Lightning-induced scatter in the E-region

An amateur radio operator observes that VHF signals are being received from stations over 2,000 km away, with the path crossing the geomagnetic equator.The signals are strongest in the late afternoon and early evening.Which propagation mode is responsible for this phenomenon?

An amateur radio operator observes that VHF signals are being received from stations over 2,000 km away, with the path crossing the geomagnetic equator.
The signals are strongest in the late afternoon and early evening.
Which propagation mode is responsible for this phenomenon?