66 lines
3.0 KiB
Markdown
66 lines
3.0 KiB
Markdown
E9E Impedance matching: matching antennas to feed lines; phasing lines; power dividers
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- [[E9E01]] (B)
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Which matching system for Yagi antennas requires the driven element to be insulated from the boom? #card
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- [[A.]] Gamma
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- [[B.]] Beta or hairpin
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- [[C.]] Shunt-fed
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- [[D.]] T-match
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- [[E9E02]] (A)
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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
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- [[A.]] Gamma match
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- [[B.]] Delta match
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- [[C.]] T-match
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- [[D.]] Stub match
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- [[E9E03]] (D)
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What matching system uses a short length of transmission line connected in parallel with the feed line at or near the feed point? #card
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- [[A.]] Gamma match
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- [[B.]] Delta match
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- [[C.]] T-match
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- [[D.]] Stub match
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- [[E9E04]] (B)
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What is the purpose of the series capacitor in a gamma match? #card
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- [[A.]] To provide DC isolation between the feed line and the antenna
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- [[B.]] To cancel unwanted inductive reactance
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- [[C.]] To provide a rejection notch that prevents the radiation of harmonics
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- [[D.]] To transform the antenna impedance to a higher value
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- [[E9E05]] (A)
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What Yagi driven element feed point impedance is required to use a beta or hairpin matching system? #card
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- [[A.]] Capacitive (driven element electrically shorter than 1/2 wavelength)
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- [[B.]] Inductive (driven element electrically longer than 1/2 wavelength)
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- [[C.]] Purely resistive
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- [[D.]] Purely reactive
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- [[E9E06]] (C)
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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
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- [[A.]] 50 ohms
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- [[B.]] 62 ohms
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- [[C.]] 75 ohms
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- [[D.]] 90 ohms
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- [[E9E07]] (B)
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What parameter describes the interaction of a load and transmission line? #card
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- [[A.]] Characteristic impedance
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- [[B.]] Reflection coefficient
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- [[C.]] Velocity factor
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- [[D.]] Dielectric constant
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- [[E9E08]] (C)
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What is a use for a Wilkinson divider? #card
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- [[A.]] To divide the operating frequency of a transmitter signal so it can be used on a lower frequency band
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- [[B.]] To feed high-impedance antennas from a low-impedance source
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- [[C.]] To divide power equally between two 50-ohm loads while maintaining 50-ohm input impedance
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- [[D.]] To divide the frequency of the input to a counter to increase its frequency range
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- [[E9E09]] (C)
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Which of the following is used to shunt feed a grounded tower at its base? #card
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- [[A.]] Double-bazooka match
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- [[B.]] Beta or hairpin match
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- [[C.]] Gamma match
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- [[D.]] All these choices are correct
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- [[E9E10]] Question Deleted (section not renumbered)
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~~
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- [[E9E11]] (A)
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What is the purpose of using multiple driven elements connected through phasing lines? #card
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- [[A.]] To control the antenna’s radiation pattern
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- [[B.]] To prevent harmonic radiation from the transmitter
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- [[C.]] To allow single-band antennas to operate on other bands
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- [[D.]] To create a low-angle radiation pattern
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