Chapter 5: Signal Propagation

Which region of the atmosphere can refract or bend HF and VHF radio waves?

• The stratosphere

• The troposphere

• The ionosphere

• The mesosphere

What is a likely cause of irregular fading of signals propagated by the ionosphere?

• Frequency shift due to Faraday rotation

• Interference from thunderstorms

• Intermodulation distortion

• Random combining of signals arriving via different paths

Tags

NGSS.HS-PS4-5

Which of the following results from the fact that signals propagated by the ionosphere are elliptically polarized?

• Digital modes are unusable

• Either vertically or horizontally polarized antennas may be used for transmission or reception

• FM voice is unusable

• Both the transmitting and receiving antennas must be of the same polarization

Tags

NGSS.HS-PS4-3

NGSS.HS-PS4-5

What is a characteristic of HF communication compared with communications on VHF and higher frequencies?

• HF antennas are generally smaller

• HF accommodates wider bandwidth signals

• Long-distance ionospheric propagation is far more common on HF

• There is less atmospheric interference (static) on HF

What is the FCC Part 97 definition of a beacon?

• A government transmitter marking the amateur radio band edges

• A bulletin sent by the FCC to announce a national emergency

• A continuous transmission of weather information authorized in the amateur bands by the National Weather Service

• An amateur station transmitting communications for the purposes of observing propagation or related experimental activities

What is generally the best time for long-distance 10 meter band propagation via the F region?

• From dawn to shortly after sunset during periods of high sunspot activity

• From shortly after sunset to dawn during periods of high sunspot activity

• From dawn to shortly after sunset during periods of low sunspot activity

• From shortly after sunset to dawn during periods of low sunspot activity

Tags

NGSS.HS-PS4-3

Which of the following bands may provide long-distance communications via the ionosphere’s F region during the peak of the sunspot cycle?

• 6 and 10 meters

• 23 centimeters

• 70 centimeters and 1.25 meters

• All these choices are correct

What is a characteristic of VHF signals received via auroral backscatter?

• They are often received from 10,000 miles or more

• They are distorted and signal strength varies considerably

• They occur only during winter nighttime hours

• They are generally strongest when your antenna is aimed west

Tags

NGSS.HS-PS4-5

Which of the following types of propagation is most commonly associated with occasional strong signals on the 10, 6, and 2 meter bands from beyond the radio horizon?

• Backscatter

• Sporadic E

• D region absorption

• Gray-line propagation

What type of propagation is responsible for allowing over-the-horizon VHF and UHF communications to ranges of approximately 300 miles on a regular basis?

• Tropospheric ducting

• D region refraction

• F2 region refraction

• Faraday rotation