Page:Electronics Technician - Volume 7 - Antennas and Wave Propagation - NAVEDTRA 14092.pdf/112

 2-23. When would a counterpoise be used?
 * 1) When easy access to the antenna base is necessary
 * 2) When the surface below is solid rock
 * 3) When the surface below is sandy ground
 * 4) All the above

2-24. Capacitive top-loading helps to increase which of the following antenna characteristics?
 * 1) Bandwidth
 * 2) Power-handling
 * 3) Directivity
 * 4) Radiation efficiency

2-25. What is the most limiting characteristic of the Yagi antenna?
 * 1) Power-handling
 * 2) Narrow bandwidth
 * 3) Physical size
 * 4) Lack of directivity

2-26. In general, log-periodic antennas have which of the following characteristics?
 * 1) Medium power handling capabilities
 * 2) High gain
 * 3) Extremely broad bandwidth
 * 4) All the above

2-27. A typical vertical monopole log periodic antenna designed to cover a frequency range of 2 to 30 MHz will require approximately how many acres of land for its ground plane system?
 * 1) 1 acre
 * 2) 2 acres
 * 3) 3 acres
 * 4) 4 acres

2-28. A sector log-periodic array can act as an antenna for a minimum of what number of transmit or receive systems?
 * 1
 * 2
 * 3
 * 4

2-29. The most distinct advantage of the rotatable log-periodic antenna is its ability to perform what function?
 * 1) Rotate 360 degrees
 * 2) Rotate from horizontal to vertical and back
 * 3) Ability to handle high transmitter power
 * 4) Ability to produce high antenna gain

2-30. What is the average power handling capability of an Inverted Cone antenna?
 * 1) 20 kw
 * 2) 30 kw
 * 3) 40 kw
 * 4) 50 kw

2-31. What determines the gain and directivity of a Rhombic antenna?
 * 1) Transmitter power
 * 2) Antenna height
 * 3) Radiated wave interaction
 * 4) Transmitted frequency

2-32. Most Whip antennas require some kind of a tuning system to improve bandwidth and power handling capabilities.
 * T
 * F

Why are UHF and. VHF antennas on board ship installed as high as possible?
 * 1) To prevent radiation hazard to personnel
 * 2) To prevent radiation hazard to ordinance
 * 3) To increase power handling capabilities
 * 4) To prevent unwanted directivity in the radiation pattern from mast structures

2-34. The central feed section for both the biconical and center-fed dipole are protected by what type of covering? 8
 * 1) SCOTCHCOAT
 * RTV
 * 1) Laminated fiberglass
 * 2) Rubber shield