Vol2 Ure2 CDC 3D153

26 Questions | Total Attempts: 114

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CDC Quizzes & Trivia

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


Questions and Answers
  • 1. 
    (213) Direct waves are radio waves that travel
    • A. 

      Long distances with few interruptions

    • B. 

      From point to point along the earth’s surface

    • C. 

      Through the air in a straight line.

    • D. 

      No more than 20 miles to the receive antenna

  • 2. 
    (213) Radio waves that travel near the earth’s surface are called
    • A. 

      Earth waves

    • B. 

      Global waves

    • C. 

      Ground waves

    • D. 

      Terrestrial waves

  • 3. 
    (213) Sky wave transmission is used for which type of communications?
    • A. 

      Long distance

    • B. 

      Subterrestrial

    • C. 

      Atmospheric

    • D. 

      Line of sight

  • 4. 
    (214) Which gives sky wave propagation its ability to communicate beyond the optical line-of sight (LOS)?
    • A. 

      Refraction

    • B. 

      Reflection

    • C. 

      Earth's conductivity

    • D. 

      Atmospheric charge

  • 5. 
    (214) Which gives sky wave propagation its ability to communicate beyond the optical line-ofsight (LOS)?
    • A. 

      Refraction

    • B. 

      Reflection

    • C. 

      Earth's conductivity

    • D. 

      Atmospheric change

  • 6. 
    (214) Frequencies higher than the critical frequency are?
    • A. 

      Returned to earth

    • B. 

      Passed into space

    • C. 

      The most desirable

    • D. 

      Refracted by the F2 layer

  • 7. 
    (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?
    • A. 

      Maximum usable frequency (MUF)

    • B. 

      Lowest usable frequency (LUF)

    • C. 

      Operating frequency

    • D. 

      Critical frequency

  • 8. 
    (214) The abbreviation FOT is derived from the term?
    • A. 

      Outbound traffic frequency

    • B. 

      Optimum tropospheric frequency

    • C. 

      Frequency of optimum transmission

    • D. 

      Frequency of outbound frequency

  • 9. 
    (214) Magneton splitting creates two waves called?
    • A. 

      Direct and indirect

    • B. 

      Ordinary and abnormal

    • C. 

      In-phase and out-of-phase

    • D. 

      Ordinary and extraordinary

  • 10. 
    (214) What occurs when a transmitted signal travels over two or more separate paths during transmission?
    • A. 

      Skip effects

    • B. 

      Modulation

    • C. 

      Multipathing

    • D. 

      Magneton splitting

  • 11. 
    (215) Which layer of the ionosphere is most important to high frequency (HF) communications?
    • A. 

      D

    • B. 

      E

    • C. 

      F

    • D. 

      Topside

  • 12. 
    (215) During what season do we have the wider range of critical frequencies and less absorption of all frequencies?
    • A. 

      Fall

    • B. 

      Winter

    • C. 

      Spring

    • D. 

      Summer

  • 13. 
    (215) What is the recombination process dependent upon?
    • A. 

      Season

    • B. 

      Time of day

    • C. 

      Regular variation

    • D. 

      Irregular variations

  • 14. 
    (215) Sunspots are disturbances?
    • A. 

      In the sun's atmosphere

    • B. 

      On the sun's surface

    • C. 

      In the ionosphere

    • D. 

      Beneath the sun's surface

  • 15. 
    (216) For communications purposes, the usable frequency spectrum ranges from?
    • A. 

      3Hz to 300 GHz+

    • B. 

      300 Hz to 3000 GHz

    • C. 

      3000 Hz to 3000 GHz

    • D. 

      30 MHz to 300 MHz

  • 16. 
    (216) What U.S. government agency divides the radio frequency (RF) spectrum into different bands?
    • A. 

      Federal Aviation Agency

    • B. 

      American National Standard Institute

    • C. 

      Federal Communications Commission

    • D. 

      Institute of Electrical & Electronics Engineers, INC

  • 17. 
    (217) Near-vertical-incidence sky (NVIS) wave operations are most effective when you’re using?
    • A. 

      Lower high frequency (HF) frequencies

    • B. 

      Higher HF frequencies

    • C. 

      Medium HF frequencies

    • D. 

      Low takeoff antenna angles

  • 18. 
    (217) What frequency band is most susceptible to jamming?
    • A. 

      Low frequency

    • B. 

      Medium frequency

    • C. 

      High Frequency

    • D. 

      Very High Frequency

  • 19. 
    (217) What frequency bands doe the MILSTAR satellite system use?
    • A. 

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

    • B. 

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

    • C. 

      Very high frequency (VHF) and SHF

    • D. 

      VHF and UHF

  • 20. 
    (218) The main very high frequency (VHF) Ultra high frequency (UHF) communications emphasis is on?
    • A. 

      Long range deployable communications

    • B. 

      Short range fixed communications

    • C. 

      Emergency communications

    • D. 

      Air-ground communications

  • 21. 
    (219) Super high frequency (SHF)/extremely high frequency (EHF) range is limited to?
    • A. 

      Scattering

    • B. 

      Line-of-sight (LOS)

    • C. 

      Earth's conductivity

    • D. 

      Atmospheric absorption

  • 22. 
    (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?
    • A. 

      Optical horizon radar

    • B. 

      Satellite communications

    • C. 

      Microwave communications

    • D. 

      Line-of-sight (LOS) communication

  • 23. 
    (220) Why isn’t very high frequency (VHF) normally used for satellite communications?
    • A. 

      The frequency is too low

    • B. 

      The frequency is too high

    • C. 

      Ionospheric refraction can occur

    • D. 

      The rate of absorption is too great

  • 24. 
    (220) When comparing the radio and optical horizons, which one is farther away and by what percent?
    • A. 

      Optical; 15

    • B. 

      Radio; 15

    • C. 

      Optical; 33

    • D. 

      Radio; 33

  • 25. 
    (220) When K is greater than 4/3, the radio horizon will?
    • A. 

      Decrease, then increase.

    • B. 

      Remain the same

    • C. 

      Decrease

    • D. 

      Increase

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