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Technician exam T3: Radio Wave Characteristics

All 35 questions in subelement T3. The exam asks 3 of them, one from each group (T3A, T3B, T3C). Answers are hidden until you open them.

Drill these 35 questions Full practice exam

T3A

  1. T3A01 Why do VHF signal strengths sometimes vary greatly when the antenna is moved only a few feet?

    1. The signal path encounters different concentrations of water vapor
    2. VHF ionospheric propagation is very sensitive to path length
    3. Multipath propagation cancels or reinforces signals
    4. The Doppler effect causes slight frequency shifts which result in changes in signal strength
    Show answer

    C. Multipath propagation cancels or reinforces signals

  2. T3A02 How does vegetation affect UHF and microwave signals?

    1. Causes knife-edge diffraction, distorting voice peaks
    2. Absorbs signals, leading to poor reception of weak signals
    3. Amplifies signals, improving reception of weak signals
    4. Has no effect
    Show answer

    B. Absorbs signals, leading to poor reception of weak signals

  3. T3A03 What antenna polarization is normally used for long-distance CW and SSB contacts on the VHF and UHF bands?

    1. Right-hand circular
    2. Left-hand circular
    3. Horizontal
    4. Vertical
    Show answer

    C. Horizontal

  4. T3A04 What is the effect of antenna cross-polarization over a line-of-sight VHF or UHF path?

    1. Modulation sidebands might become inverted
    2. Received signal strength is reduced
    3. Signals have an echo effect
    4. Nothing significant will happen
    Show answer

    B. Received signal strength is reduced

  5. T3A05 When using a directional antenna, how might your station be able to communicate with a distant repeater if buildings or obstructions are blocking the direct line of sight path?

    1. Change from vertical to horizontal polarization
    2. Try to find a path that reflects signals to the repeater
    3. Try the long path
    4. Increase the antenna SWR
    Show answer

    B. Try to find a path that reflects signals to the repeater

  6. T3A06 What is the meaning of the term “picket fencing”?

    1. Alternating transmissions during a net operation
    2. Rapid flutter on mobile signals due to multipath propagation
    3. A type of ground system used with vertical antennas
    4. Interference from cable TV in the form of carriers at fixed intervals across the band
    Show answer

    B. Rapid flutter on mobile signals due to multipath propagation

  7. T3A07 What weather condition might decrease range at microwave frequencies?

    1. High winds
    2. Low barometric pressure
    3. Precipitation
    4. Colder temperatures
    Show answer

    C. Precipitation

  8. T3A08 What is a likely cause of irregular fading of signals propagated by the ionosphere?

    1. Frequency shift due to Faraday rotation
    2. Interference from thunderstorms
    3. Intermodulation distortion
    4. Random combining of signals arriving via different paths
    Show answer

    D. Random combining of signals arriving via different paths

  9. T3A09 Which of the following results from the fact that signals propagated by the ionosphere are elliptically polarized?

    1. Digital modes are unusable
    2. Either vertically or horizontally polarized antennas may be used for transmission or reception
    3. FM voice is unusable
    4. Both the transmitting and receiving antennas must be of the same polarization
    Show answer

    B. Either vertically or horizontally polarized antennas may be used for transmission or reception

  10. T3A10 What effect does multi-path propagation have on data transmissions?

    1. Transmission rates must be increased by a factor equal to the number of separate paths observed
    2. Transmission rates must be decreased by a factor equal to the number of separate paths observed
    3. No significant changes will occur if the signals are transmitted using FM
    4. Error rates are likely to increase
    Show answer

    D. Error rates are likely to increase

  11. T3A11 Which region of the atmosphere can reflect HF radio waves?

    1. The stratosphere
    2. The troposphere
    3. The ionosphere
    4. The electrosphere
    Show answer

    C. The ionosphere

  12. T3A12 What effect does fog or rain have on 10-meter and 6-meter band signals?

    1. Absorption
    2. Little effect
    3. Deflection
    4. Increased range
    Show answer

    B. Little effect

T3B

  1. T3B01 What is the relationship between the electric and magnetic fields of an electromagnetic wave?

    1. They travel at different speeds
    2. They are in parallel
    3. They revolve in opposite directions
    4. They are at right angles
    Show answer

    D. They are at right angles

  2. T3B02 What property of a radio wave defines its polarization?

    1. The orientation of the electric field
    2. The orientation of the magnetic field
    3. The ratio of the energy in the magnetic field to the energy in the electric field
    4. The ratio of the velocity to the wavelength
    Show answer

    A. The orientation of the electric field

  3. T3B03 What are the two components of a radio wave?

    1. Impedance and reactance
    2. Voltage and current
    3. Electric and magnetic fields
    4. Ionizing and non-ionizing radiation
    Show answer

    C. Electric and magnetic fields

  4. T3B04 What is the velocity of a radio wave traveling through free space?

    1. Speed of light
    2. Speed of sound
    3. 0.86 times the speed of light
    4. 1.86 times the speed of sound
    Show answer

    A. Speed of light

  5. T3B05 What is the relationship between wavelength and frequency?

    1. Wavelength gets longer as frequency increases
    2. Wavelength gets shorter as frequency increases
    3. Wavelength is constant at all frequencies
    4. Wavelength and frequency increase as path length increases
    Show answer

    B. Wavelength gets shorter as frequency increases

  6. T3B06 What is the formula for converting frequency to approximate wavelength in meters?

    1. Wavelength in meters equals frequency in hertz multiplied by 300
    2. Wavelength in meters equals frequency in hertz divided by 300
    3. Wavelength in meters equals frequency in megahertz divided by 300
    4. Wavelength in meters equals 300 divided by frequency in megahertz
    Show answer

    D. Wavelength in meters equals 300 divided by frequency in megahertz

  7. T3B07 In addition to frequency, which of the following is used to identify amateur radio bands?

    1. The approximate wavelength in meters
    2. Traditional letter/number designators
    3. Channel numbers
    4. All these choices are correct
    Show answer

    A. The approximate wavelength in meters

  8. T3B08 What frequency range is referred to as VHF?

    1. 30 kHz to 300 kHz
    2. 30 MHz to 300 MHz
    3. 300 kHz to 3000 kHz
    4. 300 MHz to 3000 MHz
    Show answer

    B. 30 MHz to 300 MHz

  9. T3B09 What frequency range is referred to as UHF?

    1. 30 to 300 kHz
    2. 30 to 300 MHz
    3. 300 to 3000 kHz
    4. 300 to 3000 MHz
    Show answer

    D. 300 to 3000 MHz

  10. T3B10 What frequency range is referred to as HF?

    1. 300 to 3000 MHz
    2. 30 to 300 MHz
    3. 3 to 30 MHz
    4. 300 to 3000 kHz
    Show answer

    C. 3 to 30 MHz

  11. T3B11 What is the approximate velocity of a radio wave in free space?

    1. 150,000,000 meters per second
    2. 300,000,000 meters per second
    3. 300,000,000 miles per hour
    4. 150,000,000 miles per hour
    Show answer

    B. 300,000,000 meters per second

  12. T3B12 Which of these frequencies travels at the highest velocity in free space?

    1. Microwaves
    2. UHF
    3. VHF
    4. All radio frequencies travel at the same velocity
    Show answer

    D. All radio frequencies travel at the same velocity

T3C

  1. T3C01 Why are simplex UHF signals rarely heard beyond their radio horizon?

    1. They are too weak to go very far
    2. FCC regulations prohibit them from going more than 50 miles
    3. UHF signals are usually not propagated by the ionosphere
    4. UHF signals are absorbed by the ionospheric D region
    Show answer

    C. UHF signals are usually not propagated by the ionosphere

  2. T3C02 What is a characteristic of HF communication compared with communications on VHF and higher frequencies?

    1. HF antennas are generally smaller
    2. HF accommodates wider bandwidth signals
    3. Long-distance ionospheric propagation is far more common on HF
    4. There is less atmospheric interference (static) on HF
    Show answer

    C. Long-distance ionospheric propagation is far more common on HF

  3. T3C03 What is one characteristic of VHF signals received via auroral backscatter?

    1. They are often received from 10,000 miles or more
    2. They are distorted, with a characteristic raspy sound
    3. They occur only during winter nighttime hours
    4. They are generally strongest when your antenna is aimed west
    Show answer

    B. They are distorted, with a characteristic raspy sound

  4. T3C04 Which of the following types of propagation is most commonly associated with occasional strong signals on the 10-, 6-, and 2-meter bands from beyond the radio horizon?

    1. Backscatter
    2. Sporadic E
    3. D region absorption
    4. Gray-line propagation
    Show answer

    B. Sporadic E

  5. T3C05 Which of the following effects may allow radio signals to travel beyond obstructions between the transmitting and receiving stations?

    1. Knife-edge diffraction
    2. Faraday rotation
    3. Quantum tunneling
    4. Doppler shift
    Show answer

    A. Knife-edge diffraction

  6. T3C06 What type of propagation is responsible for allowing over-the-horizon VHF and UHF communications to ranges of approximately 300 miles on a regular basis?

    1. Tropospheric ducting
    2. D region refraction
    3. F2 region refraction
    4. Faraday rotation
    Show answer

    A. Tropospheric ducting

  7. T3C07 What band is best suited for communicating via meteor scatter?

    1. 33 centimeters
    2. 6 meters
    3. 2 meters
    4. 70 centimeters
    Show answer

    B. 6 meters

  8. T3C08 What causes tropospheric ducting?

    1. Discharges of lightning during electrical storms
    2. Sunspots and solar flares
    3. Updrafts from hurricanes and tornadoes
    4. Temperature inversions in the atmosphere
    Show answer

    D. Temperature inversions in the atmosphere

  9. T3C09 What is generally the best time for long-distance 10-meter band propagation via the F region?

    1. From dawn to shortly after sunset during periods of high sunspot activity
    2. From shortly after sunset to dawn during periods of high sunspot activity
    3. From dawn to shortly after sunset during periods of low sunspot activity
    4. From shortly after sunset to dawn during periods of low sunspot activity
    Show answer

    A. From dawn to shortly after sunset during periods of high sunspot activity

  10. T3C10 Which of the following bands may provide long-distance communications via the ionosphere’s F region during the peak of the sunspot cycle?

    1. 6 and 10 meters
    2. 23 centimeters
    3. 70 centimeters and 1.25 meters
    4. All these choices are correct
    Show answer

    A. 6 and 10 meters

  11. T3C11 Why is the radio horizon for VHF and UHF signals more distant than the visual horizon?

    1. Radio signals move somewhat faster than the speed of light
    2. Radio waves are not blocked by dust particles
    3. The atmosphere refracts radio waves slightly
    4. Radio waves are blocked by dust particles
    Show answer

    C. The atmosphere refracts radio waves slightly

Questions: NCVEC Question Pool Committee (public domain). Pool valid July 1, 2026 – June 30, 2030.