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Extra-Study/pages/E9E.md
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2025-05-01 15:49:18 -05:00

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E9E Impedance matching: matching antennas to feed lines; phasing lines; power dividers

  • E9E01 (B) Which matching system for Yagi antennas requires the driven element to be insulated from the boom? #card

    • A. Gamma
    • B. Beta or hairpin
    • C. Shunt-fed
    • D. T-match

  • E9E02 (A) What antenna matching system matches coaxial cable to an antenna by connecting the shield to the center of the antenna and the conductor a fraction of a wavelength to one side? #card

    • A. Gamma match
    • B. Delta match
    • C. T-match
    • D. Stub match

  • E9E03 (D) What matching system uses a short length of transmission line connected in parallel with the feed line at or near the feed point? #card

    • A. Gamma match
    • B. Delta match
    • C. T-match
    • D. Stub match

  • E9E04 (B) What is the purpose of the series capacitor in a gamma match? #card

    • A. To provide DC isolation between the feed line and the antenna
    • B. To cancel unwanted inductive reactance
    • C. To provide a rejection notch that prevents the radiation of harmonics
    • D. To transform the antenna impedance to a higher value

  • E9E05 (A) What Yagi driven element feed point impedance is required to use a beta or hairpin matching system? #card

    • A. Capacitive (driven element electrically shorter than 1/2 wavelength)
    • B. Inductive (driven element electrically longer than 1/2 wavelength)
    • C. Purely resistive
    • D. Purely reactive

  • E9E06 (C) Which of these transmission line impedances would be suitable for constructing a quarter-wave Q-section for matching a 100-ohm feed point impedance to a 50-ohm transmission line? #card

    • A. 50 ohms
    • B. 62 ohms
    • C. 75 ohms
    • D. 90 ohms

  • E9E07 (B) What parameter describes the interaction of a load and transmission line? #card

    • A. Characteristic impedance
    • B. Reflection coefficient
    • C. Velocity factor
    • D. Dielectric constant

  • E9E08 (C) What is a use for a Wilkinson divider? #card

    • A. To divide the operating frequency of a transmitter signal so it can be used on a lower frequency band
    • B. To feed high-impedance antennas from a low-impedance source
    • C. To divide power equally between two 50-ohm loads while maintaining 50-ohm input impedance
    • D. To divide the frequency of the input to a counter to increase its frequency range

  • E9E09 (C) Which of the following is used to shunt feed a grounded tower at its base? #card

    • A. Double-bazooka match
    • B. Beta or hairpin match
    • C. Gamma match
    • D. All these choices are correct

  • E9E10 Question Deleted (section not renumbered) ~~

  • E9E11 (A) What is the purpose of using multiple driven elements connected through phasing lines? #card

    • A. To control the antenna’s radiation pattern
    • B. To prevent harmonic radiation from the transmitter
    • C. To allow single-band antennas to operate on other bands
    • D. To create a low-angle radiation pattern