E3C01:

What does the radio communication term "ray tracing" describe?

1. The process in which an electronic display presents a pattern
2. Modeling a radio wave's path through the ionosphere
3. Determining the radiation pattern from an array of antennas
4. Evaluating high voltage sources for x-rays

E3C02:

What is indicated by a rising A or K index?

1. Increasing disruption of the geomagnetic field
2. Decreasing disruption of the geomagnetic field
3. Higher levels of solar UV radiation
4. An increase in the critical frequency

E3C03:

Which of the following signal paths is most likely to experience high levels of absorption when the A index or K index is elevated?

1. Transequatorial
2. Polar
3. Sporadic E
4. NVIS

E3C04:

What does the value of Bz (B sub Z) represent?

1. Geomagnetic field stability
2. Critical frequency for vertical transmissions
3. Direction and strength of the interplanetary magnetic field
4. Duration of long-delayed echoes

E3C05:

What orientation of Bz (B sub z) increases the likelihood that incoming particles from the sun will cause disturbed conditions?

1. Southward
2. Northward
3. Eastward
4. Westward

E3C06:

By how much does the VHF/UHF radio horizon distance exceed the geometric horizon?

1. By approximately 15 percent of the distance
2. By approximately twice the distance
3. By approximately 50 percent of the distance
4. By approximately four times the distance

E3C07:

Which of the following descriptors indicates the greatest solar flare intensity?

1. Class A
2. Class B
3. Class M
4. Class X

E3C08:

What does the space weather term G5 mean?

1. An extreme geomagnetic storm
2. Very low solar activity
3. Moderate solar wind
4. Waning sunspot numbers

E3C09:

How does the intensity of an X3 flare compare to that of an X2 flare?

1. 10 percent greater
2. 50 percent greater
3. Twice as great
4. Four times as great

E3C10:

What does the 304A solar parameter measure?

1. The ratio of x-ray flux to radio flux, correlated to sunspot number
2. UV emissions at 304 angstroms, correlated to the solar flux index
3. The solar wind velocity at 304 degrees from the solar equator, correlated to solar activity
4. The solar emission at 304 GHz, correlated to x-ray flare levels

E3C11:

What does VOACAP software model?

1. AC voltage and impedance
2. VHF radio propagation
3. HF propagation
4. AC current and impedance

E3C12:

How does the maximum range of ground-wave propagation change when the signal frequency is increased?

1. It stays the same
2. It increases
3. It decreases
4. It peaks at roughly 14 MHz

E3C13:

What type of polarization is best for ground-wave propagation?

1. Vertical
2. Horizontal
3. Circular
4. Elliptical

E3C14:

Why does the radio-path horizon distance exceed the geometric horizon?

1. E-region skip
2. D-region skip
3. Due to the Doppler effect
4. Downward bending due to density variations in the atmosphere

E3C15:

What might be indicated by a sudden rise in radio background noise across a large portion of the HF spectrum?

1. A temperature inversion has occurred
2. A solar flare has occurred
3. Increased transequatorial propagation is likely
4. Long-path propagation is likely