Page:Electronics Technician - Volume 7 - Antennas and Wave Propagation - NAVEDTRA 14092.pdf/109

1-43. What form of precipitation has the greatest absorption effect on RF energy?

1. Fog
2. Snow
3. Rain
4. Hail

1-44. The duct effect produced by temperature inversion allows for long—distance communications over what frequency band?

1. Vlf
2. Lf
3. Hf
4. Vhf

1-45. Which of the following factors affect(s) the amount of ground reflection loss when a radio wave is reflected from the earth's surface?

1. Angle of incidence
2. Ground irregularities
3. Electrical conductivity at the point of reflection
4. All of the above

1-46. As an RF wave increases in distance, the wavefront spreads out, reducing the amount of energy available within any given. unit of area. This action produces what type of energy loss?

1. Absorption
2. Ground reflection
3. Freespace
4. Spread

1-47. Radio waves above the MUF will experience what effect when refracted from the ionosphere?

1. They will fall short of the desired location
2. They will overshoot the desired location
3. They will be absorbed by lower layers
4. They will experience multipath fading

1-48. Variations in the ionosphere may change a preexisting muf. This is especially true because of the volatility of which of the following layers?

1. F1
2. F2
3. D
4. E

1-49. Radio waves that are propagated below the LUF are affected by what problem(s)?

1. Increased absorption
2. Higher levels of atmospheric noise
3. Higher rate of refraction
4. All of the above

1-50. The frequency that will avoid the problems of multipath fading, absorption, noise, and rapid changes in the ionosphere is known by what term?

1. LUF
2. MUF
3. FOT
4. LOS

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