3.4 KiB
3.4 KiB
G9D – Specialized antenna types and applications
- G9D01 (A)
Which of the following antenna types will be most effective as a near vertical incidence skywave (NVIS) antenna for short-skip communications on 40 meters during the day? #card
- A. A horizontal dipole placed between 1/10 and 1/4 wavelength above the ground
- B. A vertical antenna placed between 1/4 and 1/2 wavelength above the ground
- C. A horizontal dipole placed at approximately 1/2 wavelength above the ground
- D. A vertical dipole placed at approximately 1/2 wavelength above the ground
- G9D02 (D)
What is the feed point impedance of an end-fed half-wave antenna? #card
- A. Very low
- B. Approximately 50 ohms
- C. Approximately 300 ohms
- D. Very high
- G9D03 (C)
In which direction is the maximum radiation from a VHF/UHF “halo” antenna? #card
- A. Broadside to the plane of the halo
- B. Opposite the feed point
- C. Omnidirectional in the plane of the halo
- D. On the same side as the feed point
- G9D04 (A)
What is the primary function of antenna traps? #card
- A. To enable multiband operation
- B. To notch spurious frequencies
- C. To provide balanced feed point impedance
- D. To prevent out-of-band operation
- G9D05 (D)
What is an advantage of vertically stacking horizontally polarized Yagi antennas? #card
- A. It allows quick selection of vertical or horizontal polarization
- B. It allows simultaneous vertical and horizontal polarization
- C. It narrows the main lobe in azimuth
- D. It narrows the main lobe in elevation
- G9D06 (A)
Which of the following is an advantage of a log-periodic antenna? #card
- A. Wide bandwidth
- B. Higher gain per element than a Yagi antenna
- C. Harmonic suppression
- D. Polarization diversity
- G9D07 (A)
Which of the following describes a log-periodic antenna? #card
- A. Element length and spacing vary logarithmically along the boom
- 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
- G9D08 (B)
How does a “screwdriver” mobile antenna adjust its feed point impedance? #card
- A. By varying its body capacitance
- B. By varying the base loading inductance
- C. By extending and retracting the whip
- D. By deploying a capacitance hat
- G9D09 (A)
What is the primary use of a Beverage antenna? #card
- A. Directional receiving for MF and low HF bands
- B. Directional transmitting for low HF bands
- C. Portable direction finding at higher HF frequencies
- D. Portable direction finding at lower HF frequencies
- G9D10 (B)
In which direction or directions does an electrically small loop (less than 1/10 wavelength in circumference) have nulls in its radiation pattern? #card
- A. In the plane of the loop
- B. Broadside to the loop
- C. Broadside and in the plane of the loop
- D. Electrically small loops are omnidirectional
- G9D11 (D)
Which of the following is a disadvantage of multiband antennas? #card
- 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
- G9D12 (A)
What is the common name of a dipole with a single central support? #card
- A. Inverted V
- B. Inverted L
- C. Sloper
- D. Lazy H
- G9D13 Question Removed (section not renumbered)
SUBELEMENT G0 – ELECTRICAL AND RF SAFETY [2 Exam Questions – 2 Groups]