G3C01:

Which ionospheric layer is closest to the surface of Earth?

1. The D layer
2. The E layer
3. The F1 layer
4. The F2 layer

G3C02:

Where on Earth do ionospheric layers reach their maximum height?

1. Where the sun is overhead
2. Where the sun is on the opposite side of Earth
3. Where the sun is rising
4. Where the sun has just set

G3C03:

Why is the F2 region mainly responsible for the longest distance radio wave propagation?

1. Because it is the densest ionospheric layer
2. Because of the Doppler effect
3. Because it is the highest ionospheric region
4. Because of meteor trails at that level

G3C04:

What does the term "critical angle" mean, as used in radio wave propagation?

1. The long path azimuth of a distant station
2. The short path azimuth of a distant station
3. The lowest takeoff angle that will return a radio wave to Earth under specific ionospheric conditions
4. The highest takeoff angle that will return a radio wave to Earth under specific ionospheric conditions

G3C05:

Why is long-distance communication on the 40-meter, 60-meter, 80-meter, and 160-meter bands more difficult during the day?

1. The F layer absorbs signals at these frequencies during daylight hours
2. The F layer is unstable during daylight hours
3. The D layer absorbs signals at these frequencies during daylight hours
4. The E layer is unstable during daylight hours

G3C06:

What is a characteristic of HF scatter?

1. Phone signals have high intelligibility
2. Signals have a fluttering sound
3. There are very large, sudden swings in signal strength
4. Scatter propagation occurs only at night

G3C07:

What makes HF scatter signals often sound distorted?

1. The ionospheric layer involved is unstable
2. Ground waves are absorbing much of the signal
3. The E-region is not present
4. Energy is scattered into the skip zone through several different radio wave paths

G3C08:

Why are HF scatter signals in the skip zone usually weak?

1. Only a small part of the signal energy is scattered into the skip zone
2. Signals are scattered from the magnetosphere, which is not a good reflector
3. Propagation is through ground waves, which absorb most of the signal energy
4. Propagation is through ducts in the F region, which absorb most of the energy

G3C09:

What type of propagation allows signals to be heard in the transmitting station's skip zone?

1. Faraday rotation
2. Scatter
3. Chordal hop
4. Short-path

G3C10:

What is Near Vertical Incidence Skywave (NVIS) propagation?

1. Propagation near the MUF
2. Short distance MF or HF propagation using high elevation angles
3. Long path HF propagation at sunrise and sunset
4. Double hop propagation near the LUF

G3C11:

Which ionospheric layer is the most absorbent of long skip signals during daylight hours on frequencies below 10 MHz?

1. The F2 layer
2. The F1 layer
3. The E layer
4. The D layer