Amateur Extra exam E3: Radio Wave Propagation

All 39 questions in subelement E3. The exam asks 3 of them, one from each group (E3A, E3B, E3C). Answers are hidden until you open them.

E3A

1. E3A01 What is the approximate maximum separation measured along the surface of the Earth between two stations communicating by EME?

   1. 2,000 miles, if the moon is at perigee
   2. 2,000 miles, if the moon is at apogee
   3. 5,000 miles, if the moon is at perigee
   4. 12,000 miles, if the moon is “visible” by both stations
   Show answer

   D. 12,000 miles, if the moon is “visible” by both stations

2. E3A02 What characterizes libration fading of an EME signal?

   1. A slow change in the pitch of the CW signal
   2. A fluttery, irregular fading
   3. A gradual loss of signal as the sun rises
   4. The returning echo is several hertz lower in frequency than the transmitted signal
   Show answer

   B. A fluttery, irregular fading

3. E3A03 When scheduling EME contacts, which of these conditions will generally result in the least path loss?

   1. When the Moon is at perigee
   2. When the Moon is full
   3. When the Moon is at apogee
   4. When the MUF is above 30 MHz
   Show answer

   A. When the Moon is at perigee

4. E3A04 In what direction does an electromagnetic wave travel?

   1. It depends on the phase angle of the magnetic field
   2. It travels parallel to the electric and magnetic fields
   3. It depends on the phase angle of the electric field
   4. It travels at a right angle to the electric and magnetic fields
   Show answer

   D. It travels at a right angle to the electric and magnetic fields

5. E3A05 How are the component fields of an electromagnetic wave oriented?

   1. They are parallel
   2. They are tangential
   3. They are at right angles
   4. They are 90 degrees out of phase
   Show answer

   C. They are at right angles

6. E3A06 What should be done to continue a long-distance contact when the MUF for that path decreases due to darkness?

   1. Switch to a higher frequency HF band
   2. Switch to a lower frequency HF band
   3. Change to an antenna with a higher takeoff angle
   4. Change to an antenna with greater beam width
   Show answer

   B. Switch to a lower frequency HF band

7. E3A07 Atmospheric ducts capable of propagating microwave signals often form over what geographic feature?

   1. Mountain ranges
   2. Stratocumulus clouds
   3. Large bodies of water
   4. Nimbus clouds
   Show answer

   C. Large bodies of water

8. E3A08 When a meteor strikes the Earth’s atmosphere, a linear ionized region is formed at what region of the ionosphere?

   1. The E region
   2. The F1 region
   3. The F2 region
   4. The D region
   Show answer

   A. The E region

9. E3A09 Which of the following frequency ranges is most suited for meteor-scatter communications?

   1. 1.8 MHz - 1.9 MHz
   2. 10 MHz - 14 MHz
   3. 28 MHz - 148 MHz
   4. 220 MHz - 450 MHz
   Show answer

   C. 28 MHz - 148 MHz

10. E3A10 What determines the speed of electromagnetic waves through a medium?

    1. Resistance and reactance
    2. Evanescence
    3. Birefringence
    4. The index of refraction
    Show answer

    D. The index of refraction

11. E3A11 What is a typical range for tropospheric duct propagation of microwave signals?

    1. 10 miles to 50 miles
    2. 100 miles to 300 miles
    3. 1,200 miles
    4. 2,500 miles
    Show answer

    B. 100 miles to 300 miles

12. E3A12 What is most likely to result in auroral propagation?

    1. Meteor showers
    2. Quiet geomagnetic conditions
    3. Severe geomagnetic storms
    4. Extreme low-pressure areas in polar regions
    Show answer

    C. Severe geomagnetic storms

13. E3A13 Which of these emission modes is best for auroral propagation?

    1. CW
    2. SSB
    3. FM
    4. RTTY
    Show answer

    A. CW

14. E3A14 What are circularly polarized electromagnetic waves?

    1. Waves with an electric field bent into a circular shape
    2. Waves with rotating electric and magnetic fields
    3. Waves that circle Earth
    4. Waves produced by a loop antenna
    Show answer

    B. Waves with rotating electric and magnetic fields

E3B

1. E3B01 Where is transequatorial propagation (TEP) most likely to occur?

   1. Between points separated by 2,000 miles to 3,000 miles over a path perpendicular to the geomagnetic equator
   2. Between points located 1,500 miles to 2,000 miles apart on the geomagnetic equator
   3. Between points located at each other’s antipode
   4. Through the region where the terminator crosses the geographic equator
   Show answer

   A. Between points separated by 2,000 miles to 3,000 miles over a path perpendicular to the geomagnetic equator

2. E3B02 What is the approximate maximum range for signals using transequatorial propagation?

   1. 1,000 miles
   2. 2,500 miles
   3. 5,000 miles
   4. 7,500 miles
   Show answer

   C. 5,000 miles

3. E3B03 At what time of day is transequatorial propagation most likely to occur?

   1. Morning
   2. Noon
   3. Afternoon or early evening
   4. Late at night
   Show answer

   C. Afternoon or early evening

4. E3B04 What are “extraordinary” and “ordinary” waves?

   1. Extraordinary waves exhibit rare long-skip propagation, compared to ordinary waves, which travel shorter distances
   2. Independently propagating, elliptically polarized waves created in the ionosphere
   3. Long-path and short-path waves
   4. Refracted rays and reflected waves
   Show answer

   B. Independently propagating, elliptically polarized waves created in the ionosphere

5. E3B05 Which of the following paths is most likely to support long-distance propagation on 160 meters?

   1. A path entirely in sunlight
   2. Paths at high latitudes
   3. A direct north-south path
   4. A path entirely in darkness
   Show answer

   D. A path entirely in darkness

6. E3B06 On which of the following amateur bands is long-path propagation most frequent?

   1. 160 meters and 80 meters
   2. 40 meters and 20 meters
   3. 10 meters and 6 meters
   4. 6 meters and 2 meters
   Show answer

   B. 40 meters and 20 meters

7. E3B07 What effect does lowering a signal’s transmitted elevation angle have on ionospheric HF skip propagation?

   1. Faraday rotation becomes stronger
   2. The MUF decreases
   3. The distance covered by each hop increases
   4. The critical frequency increases
   Show answer

   C. The distance covered by each hop increases

8. E3B08 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 8 MHz
   Show answer

   C. It decreases

9. E3B09 At what time of year is sporadic-E propagation most likely to occur?

   1. Around the solstices, especially the summer solstice
   2. Around the solstices, especially the winter solstice
   3. Around the equinoxes, especially the spring equinox
   4. Around the equinoxes, especially the fall equinox
   Show answer

   A. Around the solstices, especially the summer solstice

10. E3B10 What is the effect of chordal-hop propagation?

    1. The signal experiences less loss compared to multi-hop propagation, which uses Earth as a reflector
    2. The MUF for chordal-hop propagation is much lower than for normal skip propagation
    3. Atmospheric noise is reduced in the direction of chordal-hop propagation
    4. Signals travel faster along ionospheric chords
    Show answer

    A. The signal experiences less loss compared to multi-hop propagation, which uses Earth as a reflector

11. E3B11 At what time of day is sporadic-E propagation most likely to occur?

    1. Between midnight and sunrise
    2. Between sunset and midnight
    3. Between sunset and sunrise
    4. Between sunrise and sunset
    Show answer

    D. Between sunrise and sunset

12. E3B12 What is chordal-hop propagation?

    1. Propagation away from the great circle bearing between stations
    2. Successive ionospheric refractions without an intermediate reflection from the ground
    3. Propagation across the geomagnetic equator
    4. Signals reflected back toward the transmitting station
    Show answer

    B. Successive ionospheric refractions without an intermediate reflection from the ground

13. E3B13 What type of polarization is supported by ground-wave propagation?

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

    A. Vertical

E3C

1. E3C01 What is the cause of short-term radio blackouts?

   1. Coronal mass ejections
   2. Sunspots on the solar equator
   3. North-oriented interplanetary magnetic field
   4. Solar flares
   Show answer

   D. Solar flares

2. E3C02 What is indicated by a rising A-index or K-index?

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

   A. Increasing disturbance of the geomagnetic field

3. 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. Through the auroral oval
   3. Sporadic-E
   4. NVIS
   Show answer

   B. Through the auroral oval

4. E3C04 What does the value of Bz (B sub z) represent?

   1. Geomagnetic field stability
   2. Critical frequency for vertical transmissions
   3. North-south strength of the interplanetary magnetic field
   4. Duration of long-delayed echoes
   Show answer

   C. North-south strength of the interplanetary magnetic field

5. E3C05 What orientation of Bz (B sub z) increases the likelihood that charged particles from the Sun will cause disturbed conditions?

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

   A. Southward

6. E3C06 How does the VHF/UHF radio horizon compare to the geographic horizon?

   1. It is approximately 15 percent farther
   2. It is approximately 20 percent nearer
   3. It is approximately 50 percent farther
   4. They are approximately the same
   Show answer

   A. It is approximately 15 percent farther

7. E3C07 Which of the following indicates the greatest solar flare intensity?

   1. Class A
   2. Class Z
   3. Class M
   4. Class X
   Show answer

   D. Class X

8. E3C08 Which of the following is the space-weather term for an extreme geomagnetic storm?

   1. B9
   2. X5
   3. M9
   4. G5
   Show answer

   D. G5

9. E3C09 What type of data is reported by amateur radio propagation reporting networks?

   1. Solar flux
   2. Electric field intensity
   3. Magnetic declination
   4. Digital-mode and CW signals
   Show answer

   D. Digital-mode and CW signals

10. 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 an angle of 304 degrees from the solar equator, correlated to geomagnetic storms
    4. The solar emission at 304 GHz, correlated to X-ray flare levels
    Show answer

    B. UV emissions at 304 angstroms, correlated to the solar flux index

11. E3C11 What does VOACAP software model?

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

    C. HF propagation

12. E3C12 Which of the following is 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 coronal mass ejection impact or a solar flare has occurred
    3. Transequatorial propagation on 6 meters is likely
    4. Long-path propagation on the higher HF bands is likely
    Show answer

    B. A coronal mass ejection impact or a solar flare has occurred

Questions: NCVEC Question Pool Committee (public domain). Pool valid July 1, 2024 – June 30, 2028.