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RF Transmission & Antenna Systems Flashcards

7 cards from real CBT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 RF Transmission & Antenna Systems flashcards as text

  1. What is the primary purpose of a transmission line in a broadcast RF system?

    Answer: To transfer RF energy from the transmitter to the antenna with minimal loss

    A transmission line's primary role is to efficiently transfer RF energy from the transmitter output to the antenna while minimizing losses due to reflection and attenuation.

  2. Which parameter describes the ratio of reflected wave voltage to incident wave voltage on a transmission line?

    Answer: Voltage Reflection Coefficient (Γ)

    The Voltage Reflection Coefficient (Γ) is the ratio of the reflected voltage to the incident voltage, and is the fundamental quantity from which SWR and return loss are derived.

  3. A broadcast FM antenna has a gain of 6 dBd. Approximately how many times greater is its effective radiated power compared to a dipole radiating the same transmitter power?

    Answer: 4 times

    6 dBd corresponds to a power ratio of 10^(6/10) ≈ 4, meaning the antenna focuses energy to produce four times the ERP of a reference dipole.

  4. What is the standard characteristic impedance of most coaxial transmission lines used in broadcast RF systems?

    Answer: 50 ohms

    50 ohms is the standard characteristic impedance for broadcast transmitter output and coaxial transmission lines, as it balances low loss and high power handling.

  5. What does VSWR of 1:1 indicate about a transmission line system?

    Answer: The load is perfectly matched and no power is reflected

    A VSWR of 1:1 indicates a perfect impedance match between the transmission line and the load, meaning zero reflected power and maximum power transfer to the antenna.

  6. Which type of antenna is most commonly used for omnidirectional FM broadcast coverage?

    Answer: Circularly polarized panel antenna or batwing antenna

    Circularly polarized panel antennas (such as batwing or Superturnstile designs) are standard for FM broadcast because they provide omnidirectional horizontal radiation and circular polarization as required by the FCC.

  7. What is the purpose of an antenna diplexer in a broadcast facility?

    Answer: To combine two transmitters operating on different frequencies onto a single antenna

    An antenna diplexer allows two transmitters operating on different frequencies to share a single antenna system without interfering with each other.