Vol2 Ure2 CDC 3D153

26 Questions | Attempts: 114
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  • 1/26 Questions

    (214) The abbreviation FOT is derived from the term?

    • Outbound traffic frequency
    • Optimum tropospheric frequency
    • Frequency of optimum transmission
    • Frequency of outbound frequency
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About This Quiz

This is a URE #2 for CDC 3D153 and is to be used as a study aid for the RF transmission systems CDC's.

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  • 2. 

    (214) In high frequency (HF) communications, the lowest frequency that arrives at the distant receiver on 90 percent of the undisturbed days of the month is called the?

    • Maximum usable frequency (MUF)

    • Lowest usable frequency (LUF)

    • Operating frequency

    • Critical frequency

    Correct Answer
    A. Lowest usable frequency (LUF)
  • 3. 

    (213) Radio waves that travel near the earth’s surface are called

    • Earth waves

    • Global waves

    • Ground waves

    • Terrestrial waves

    Correct Answer
    A. Ground waves
  • 4. 

    (215) Sunspots are disturbances?

    • In the sun's atmosphere

    • On the sun's surface

    • In the ionosphere

    • Beneath the sun's surface

    Correct Answer
    A. On the sun's surface
  • 5. 

    (216) What U.S. government agency divides the radio frequency (RF) spectrum into different bands?

    • Federal Aviation Agency

    • American National Standard Institute

    • Federal Communications Commission

    • Institute of Electrical & Electronics Engineers, INC

    Correct Answer
    A. Federal Communications Commission
  • 6. 

    (219) Super high frequency (SHF)/extremely high frequency (EHF) range is limited to?

    • Scattering

    • Line-of-sight (LOS)

    • Earth's conductivity

    • Atmospheric absorption

    Correct Answer
    A. Line-of-sight (LOS)
  • 7. 

    (213) Sky wave transmission is used for which type of communications?

    • Long distance

    • Subterrestrial

    • Atmospheric

    • Line of sight

    Correct Answer
    A. Long distance
  • 8. 

    (214) Which gives sky wave propagation its ability to communicate beyond the optical line-ofsight (LOS)?

    • Refraction

    • Reflection

    • Earth's conductivity

    • Atmospheric change

    Correct Answer
    A. Refraction
  • 9. 

    (214) Frequencies higher than the critical frequency are?

    • Returned to earth

    • Passed into space

    • The most desirable

    • Refracted by the F2 layer

    Correct Answer
    A. Passed into space
  • 10. 

    (214) Which gives sky wave propagation its ability to communicate beyond the optical line-of sight (LOS)?

    • Refraction

    • Reflection

    • Earth's conductivity

    • Atmospheric charge

    Correct Answer
    A. Refraction
  • 11. 

    (216) For communications purposes, the usable frequency spectrum ranges from?

    • 3Hz to 300 GHz+

    • 300 Hz to 3000 GHz

    • 3000 Hz to 3000 GHz

    • 30 MHz to 300 MHz

    Correct Answer
    A. 3Hz to 300 GHz+
  • 12. 

    (220) In a move to overcome the limited range of forward propagation by tropospheric scatter (FPTS) without requiring many costly relay systems, what was developed?

    • Optical horizon radar

    • Satellite communications

    • Microwave communications

    • Line-of-sight (LOS) communication

    Correct Answer
    A. Satellite communications
  • 13. 

    (215) What is the recombination process dependent upon?

    • Season

    • Time of day

    • Regular variation

    • Irregular variations

    Correct Answer
    A. Time of day
  • 14. 

    (214) Magneton splitting creates two waves called?

    • Direct and indirect

    • Ordinary and abnormal

    • In-phase and out-of-phase

    • Ordinary and extraordinary

    Correct Answer
    A. Ordinary and extraordinary
  • 15. 

    (215) Which layer of the ionosphere is most important to high frequency (HF) communications?

    • D

    • E

    • F

    • Topside

    Correct Answer
    A. F
  • 16. 

    (220) A radio wave originated at a center source in free space. If the field strength at one mile from the source has a field strength of 100 microvolts per meter, what is the field strength at two miles?

    • 25 microvolts per metear

    • 50 microvolts per meter

    • 100 microvolts per meter

    • 200 microvolts per meter

    Correct Answer
    A. 50 microvolts per meter
  • 17. 

    (217) What frequency bands doe the MILSTAR satellite system use?

    • High frequency (HF) and Ultra high Frequency (UHF)

    • Super-High Frequency (SHF) and Extremely high frequency (EHF)

    • Very high frequency (VHF) and SHF

    • VHF and UHF

    Correct Answer
    A. Super-High Frequency (SHF) and Extremely high frequency (EHF)
  • 18. 

    (217) What frequency band is most susceptible to jamming?

    • Low frequency

    • Medium frequency

    • High Frequency

    • Very High Frequency

    Correct Answer
    A. High Frequency
  • 19. 

    (213) Direct waves are radio waves that travel

    • Long distances with few interruptions

    • From point to point along the earth’s surface

    • Through the air in a straight line.

    • No more than 20 miles to the receive antenna

    Correct Answer
    A. Through the air in a straight line.
  • 20. 

    (215) During what season do we have the wider range of critical frequencies and less absorption of all frequencies?

    • Fall

    • Winter

    • Spring

    • Summer

    Correct Answer
    A. Winter
  • 21. 

    (218) The main very high frequency (VHF) Ultra high frequency (UHF) communications emphasis is on?

    • Long range deployable communications

    • Short range fixed communications

    • Emergency communications

    • Air-ground communications

    Correct Answer
    A. Air-ground communications
  • 22. 

    (214) What occurs when a transmitted signal travels over two or more separate paths during transmission?

    • Skip effects

    • Modulation

    • Multipathing

    • Magneton splitting

    Correct Answer
    A. Multipathing
  • 23. 

    (217) Near-vertical-incidence sky (NVIS) wave operations are most effective when you’re using?

    • Lower high frequency (HF) frequencies

    • Higher HF frequencies

    • Medium HF frequencies

    • Low takeoff antenna angles

    Correct Answer
    A. Lower high frequency (HF) frequencies
  • 24. 

    (220) When comparing the radio and optical horizons, which one is farther away and by what percent?

    • Optical; 15

    • Radio; 15

    • Optical; 33

    • Radio; 33

    Correct Answer
    A. Radio; 15
  • 25. 

    (220) When K is greater than 4/3, the radio horizon will?

    • Decrease, then increase.

    • Remain the same

    • Decrease

    • Increase

    Correct Answer
    A. Increase
  • 26. 

    (220) Why isn’t very high frequency (VHF) normally used for satellite communications?

    • The frequency is too low

    • The frequency is too high

    • Ionospheric refraction can occur

    • The rate of absorption is too great

    Correct Answer
    A. The frequency is too low

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  • Mar 20, 2022
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  • Aug 20, 2012
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