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. 1
2. 2
3. 3
4. 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.

1. T
2. 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?

1. SCOTCHCOAT
2. RTV
3. Laminated fiberglass
4. Rubber shield

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