11 terms

G9D Antennas and Feed Lines

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G9D01 -What does the term "NVIS" mean as related to antennas? A. Nearly Vertical Inductance System B. Non-Visible Installation Specification C. Non-Varying Impedance Smoothing D. Near Vertical Incidence Sky wave
(D)
G9D02 -Which of the following is an advantage of an NVIS antenna? A. Low vertical angle radiation for working stations out to ranges of several thousand kilometers B. High vertical angle radiation for working stations within a radius of a few hundred kilometers C. High forward gain D. All of these choices are correct
(B)
G9D03 -At what height above ground is an NVIS antenna typically installed? A. As close to one-half wave as possible B. As close to one wavelength as possible C. Height is not critical as long as it is significantly more than 1/2 wavelength D. Between 1/10 and 1/4 wavelength
(D)
G9D04 -What is the primary purpose of antenna traps? A. To permit multiband operation B. To notch spurious frequencies C. To provide balanced feed-point impedance D. To prevent out of band operation
(A)
G9D05 -What is the advantage of vertical stacking of horizontally polarized Yagi antennas? A. Allows quick selection of vertical or horizontal polarization B. Allows simultaneous vertical and horizontal polarization C. Narrows the main lobe in azimuth D. Narrows the main lobe in elevation
(D)
G9D06 -Which of the following is an advantage of a log periodic antenna? A. Wide bandwidth B. Higher gain per element than a Yagi antenna C. Harmonic suppression D. Polarization diversity
(A)
G9D07 -Which of the following describes a log periodic antenna? A. Length and spacing of the elements increases logarithmically from one end of the boom to the other B. Impedance varies periodically as a function of frequency C. Gain varies logarithmically as a function of frequency D. SWR varies periodically as a function of boom length
(A)
G9D08 -Why is a Beverage antenna not used for transmitting? A. Its impedance is too low for effective matching B. It has high losses compared to other types of antennas C. It has poor directivity D. All of these choices are correct
(B)
G9D09 -Which of the following is an application for a Beverage antenna? A. Directional transmitting for low HF bands B. Directional receiving for low HF bands C. Portable direction finding at higher HF frequencies D. Portable direction finding at lower HF frequencies
(B)
G9D10 -Which of the following describes a Beverage antenna? A. A vertical antenna constructed from beverage cans B. A broad-band mobile antenna C. A helical antenna for space reception D. A very long and low directional receiving antenna
(D)
G9D11 -Which of the following is a disadvantage of multiband antennas? A. They present low impedance on all design frequencies B. They must be used with an antenna tuner C. They must be fed with open wire line D. They have poor harmonic rejection
(D)