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Technician pool · Subelement T9

Technician exam T9: Antennas and Feed Lines

All 23 questions in subelement T9. The exam asks 2 of them, one from each group (T9A, T9B). Answers are hidden until you open them.

Drill these 23 questions Full practice exam

T9A

  1. T9A01 What is a beam antenna?

    1. An antenna built from square aluminum beams
    2. An omnidirectional antenna invented by Clarence Beam
    3. An antenna that concentrates signals in one direction
    4. An antenna that focuses the signal into two intense rays
    Show answer

    C. An antenna that concentrates signals in one direction

  2. T9A02 Which of the following describes a type of antenna loading?

    1. Electrically lengthening by inserting inductors in radiating elements
    2. Inserting a resistor in the radiating portion of the antenna to make it resonant
    3. Installing a spring in the base of a mobile vertical antenna to make it more flexible
    4. Strengthening the radiating elements of a beam antenna to better resist wind damage
    Show answer

    A. Electrically lengthening by inserting inductors in radiating elements

  3. T9A03 How is the polarization of an antenna described?

    1. By the shape of the driven element
    2. By the orientation of the electric field
    3. By the orientation of the magnetic field
    4. By the direction of radiation
    Show answer

    B. By the orientation of the electric field

  4. T9A04 What is a disadvantage of a handheld radio transceiver’s short flexible antenna compared to a full-sized quarter-wave antenna?

    1. It has low efficiency
    2. It transmits only circularly polarized signals
    3. It is more susceptible to receiver desensitization
    4. It only works on analog signals, not digital ones
    Show answer

    A. It has low efficiency

  5. T9A05 Which of the following increases the resonant frequency of a dipole antenna?

    1. Lengthening it
    2. Inserting coils in series with radiating wires
    3. Shortening it
    4. Adding capacitive loading to the ends of the radiating wires
    Show answer

    C. Shortening it

  6. T9A06 Which of the following types of antennas offers the greatest gain?

    1. 5/8 wave vertical
    2. Isotropic
    3. J pole
    4. Yagi
    Show answer

    D. Yagi

  7. T9A07 What is a potential drawback of using a handheld VHF transceiver inside a vehicle that lacks an externally mounted antenna?

    1. Signal strength is reduced due to the shielding effect of the vehicle
    2. The bandwidth of the antenna will decrease, increasing SWR
    3. The SWR might decrease, decreasing the signal strength
    4. The handheld will overheat due to reflected power in the vehicle
    Show answer

    A. Signal strength is reduced due to the shielding effect of the vehicle

  8. T9A08 Why is a 19-inch-long vertical antenna often used on 2 meters?

    1. It has high gain
    2. It is a resonant half-wave
    3. It is a resonant quarter-wave
    4. It has low RF radiation exposure
    Show answer

    C. It is a resonant quarter-wave

  9. T9A09 What is an advantage of a 5/8-wavelength whip antenna for VHF or UHF mobile service compared to a 1/4-wave antenna?

    1. It has more gain
    2. It radiates at a higher angle
    3. It has lower SWR
    4. It has lower impedance
    Show answer

    A. It has more gain

  10. T9A10 In which direction does a half-wave dipole antenna radiate the strongest signal?

    1. Equally in all directions
    2. Off the ends of the antenna
    3. In the direction of the feed line
    4. Broadside to the antenna
    Show answer

    D. Broadside to the antenna

  11. T9A11 What is antenna gain?

    1. The additional power that is added to the transmitter power
    2. The additional power that is required in the antenna when transmitting on a higher frequency
    3. The increase in signal strength in a specified direction compared to a reference antenna
    4. The increase in impedance on receive or transmit compared to a reference antenna
    Show answer

    C. The increase in signal strength in a specified direction compared to a reference antenna

T9B

  1. T9B01 Which of the following connectors should be carefully taped for weather protection when used outdoors?

    1. PL259
    2. BNC
    3. Type N
    4. All these choices are correct
    Show answer

    D. All these choices are correct

  2. T9B02 What is the most common impedance of coaxial cables used in amateur radio?

    1. 8 ohms
    2. 50 ohms
    3. 600 ohms
    4. 12 ohms
    Show answer

    B. 50 ohms

  3. T9B03 Why is coaxial cable the most common feed line for amateur radio antenna systems?

    1. It is easy to use and requires few special installation considerations
    2. It has less loss than any other type of feed line
    3. It can handle more power than any other type of feed line
    4. It is less expensive than any other type of feed line
    Show answer

    A. It is easy to use and requires few special installation considerations

  4. T9B04 What is the major function of an antenna tuner (antenna coupler)?

    1. It matches the antenna system impedance to the transceiver's output impedance
    2. It helps a receiver automatically tune in weak stations
    3. It allows an antenna to be used on both transmit and receive
    4. It automatically selects the proper antenna for the frequency band being used
    Show answer

    A. It matches the antenna system impedance to the transceiver's output impedance

  5. T9B05 What happens as the frequency of a signal in coaxial cable is increased?

    1. The characteristic impedance decreases
    2. The loss decreases
    3. The characteristic impedance increases
    4. The loss increases
    Show answer

    D. The loss increases

  6. T9B06 Which of the following connector types is most suitable as an RF connector for frequencies above 400 MHz?

    1. PL-259
    2. Type N
    3. RS-213
    4. DB-25
    Show answer

    B. Type N

  7. T9B07 Which of the following is true of PL-259 type coax connectors?

    1. They are preferred for microwave operation
    2. They are watertight
    3. They are commonly used at HF and VHF frequencies
    4. They are a bayonet-type connector
    Show answer

    C. They are commonly used at HF and VHF frequencies

  8. T9B08 Which of the following is a source of loss in coaxial feed line?

    1. Water intrusion into coaxial connectors
    2. High SWR
    3. Multiple connectors in the line
    4. All these choices are correct
    Show answer

    D. All these choices are correct

  9. T9B09 What can cause erratic changes in SWR?

    1. Local thunderstorm
    2. Loose connection in the antenna or feed line
    3. Over-modulation
    4. Overload from a strong local station
    Show answer

    B. Loose connection in the antenna or feed line

  10. T9B10 What is the electrical difference between RG-58 and RG-213 coaxial cable?

    1. There is no significant difference between the two types
    2. RG-58 cable has two shields
    3. RG-213 cable has less loss at a given frequency
    4. RG-58 cable can handle higher power levels
    Show answer

    C. RG-213 cable has less loss at a given frequency

  11. T9B11 Which of the following types of feed line has the lowest loss?

    1. 50-ohm flexible coax
    2. Multi-conductor unbalanced cable
    3. Air-insulated hardline
    4. 75-ohm flexible coax
    Show answer

    C. Air-insulated hardline

  12. T9B12 What is standing wave ratio (SWR)?

    1. A measure of how well a load is matched to a transmission line
    2. The ratio of amplifier power output to input
    3. The transmitter efficiency ratio
    4. An indication of the quality of your station’s ground connection
    Show answer

    A. A measure of how well a load is matched to a transmission line

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