FREE HAM Radio Extra Class Test Radio Wave Propagation Questions and Answers

Question 1

Which of the following atmospheric conditions is most likely to cause tropospheric ducting of VHF and UHF signals?

Accepted Answer

A temperature inversion over a large body of water.

Answer

A fast-moving cold front with heavy precipitation.

Answer

A strong, low-pressure system with high winds.

Answer

A dry, unstable air mass with significant vertical mixing.

Question 2

An amateur operator is attempting a long-distance contact on the 160-meter band. Which propagation mode offers the best chance for success when both the transmitting and receiving stations are located along the terminator?

Accepted Answer

Gray-line propagation

Answer

Transequatorial propagation (TEP)

Answer

Meteor scatter

Answer

Auroral backscatter

Question 3

A characteristic distortion of signals propagated via aurora, often described as a 'raspy' or 'buzzing' sound on CW and SSB signals, is primarily caused by what phenomenon?

Accepted Answer

Rapid and random phase shifts from moving ionized particles.

Answer

Faraday rotation of the signal's polarization.

Answer

Absorption by the D-layer.

Answer

Multipath propagation through different ionospheric layers.

Question 4

For which of the following scenarios would Near Vertical Incidence Skywave (NVIS) propagation be most suitable?

Accepted Answer

Establishing reliable communication between two stations 50 miles apart in mountainous terrain on 80 meters.

Answer

Making a contact from North America to Australia on 20 meters.

Answer

Bouncing a 2-meter signal off the moon to a distant station (EME).

Answer

Communicating via a VHF repeater located on a tall building.

Question 5

Which of the following describes a key characteristic of transequatorial propagation (TEP) on the 6-meter and 2-meter bands?

Accepted Answer

It often occurs in the late afternoon or early evening between stations equidistant from the magnetic equator.

Answer

It is most common during the winter at midday.

Answer

It provides a path between stations at high latitudes.

Answer

Signals are typically clear with very slow, gentle fading.

Question 6

An operator is using a high-speed digital mode (MSK144) to attempt a contact. The band appears to be dead, but suddenly a very brief signal is decoded. This is characteristic of which propagation mode?

Accepted Answer

Meteor scatter

Answer

Tropospheric scatter

Answer

Sporadic-E

Answer

Gray-line propagation