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?
 * Fog
 * 1) Snow
 * 2) Rain
 * 3) Hail

1-44. The duct effect produced by temperature inversion allows for long—distance communications over what frequency band?
 * Vlf
 * Lf
 * Hf
 * 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?
 * F1
 * F2
 * D
 * 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? 5
 * LUF
 * MUF
 * FOT
 * LOS