NEETS MODULE 18 CHAPTER 1 RADAR FUNDAMENTALS
Q1. Radar surface-angular measurements are referenced to true north and measured in what plane?
Q2. The distance from a radar set to a target measured along the line of sight is identified by whatterm?
Q3. What is the speed of electromagnetic energy traveling through air?
Q4. How much time is required for electromagnetic energy to travel 1 nautical mile and return to thesource?
Q5. In addition to recovery time, what determines the minimum range of a radar set?
Q6. Atmospheric interference with the travel of electromagnetic energy increases with what rf energycharacteristic?
Q7. How is prt related to prf?
Q8. What type of radar transmitter power is measured over a period of time?
Q9. What term is used to describe the product of pulse width and pulse-repetition frequency?
Q10. What type of target bearing is referenced to your ship?
Q11. What type of radar detects range, bearing, and height?
Q12. What characteristic(s) of radiated energy is (are) altered to achieve electronic scanning?
Q13. What term is used to describe the ability of a radar system to distinguish between targets that areclose together?
Q14. The degree of bearing resolution for a given radar system depends on what two factors?
Q15. What happens to the speed of electromagnetic energy traveling through air as the altitudeincreases?
Q16. What term is used to describe a situation in which atmospheric temperature first increases withaltitude and then begins to decrease?
Q17. What radar subsystem supplies timing signals to coordinate the operation of the completesystem?
Q18. When a transmitter uses a high-power oscillator to produce the output pulse, what switches theoscillator on and off?
Q19. What radar component permits the use of a single antenna for both transmitting and receiving?
Q20. What is the simplest type of scanning?
Q21. How does the operator of a single-lobe scanning system determine when the target moves off thelobe axis?
Q22. What are the two basic methods of scanning?
Q23. Rotation of an rf-feed source to produce a conical scan pattern is identified by what term?
Q24. The Doppler effect causes a change in what aspect of rf energy that strikes a moving object?
Q25. The Doppler variation is directly proportional to what radar contact characteristic?
Q26. The Doppler method of object detection is best for what type objects?
Q27. The beat frequency in a swept-frequency transmitter provides what contact information?
Q28. What factor determines the difference between the transmitted frequency and the receivedfrequency in an fm transmitter?
Q29. What type of objects are most easily detected by an fm system?
Q30. What transmission method does NOT depend on relative frequency or target motion?
Q31. What transmission method uses a stable cw reference oscillator, which is locked in phase with thetransmitter frequency?
Q32. What type of radar provides continuous range, bearing, and elevation data on an object?
Q33. Radar altimeters use what type of transmission signal?
Q34. A surface-search radar normally scans how many degrees of azimuth?
Q35. What limits the maximum range of a surface-search radar?
Q36. What is the shape of the beam of a surface-search radar?
Q37. Air-search radar is divided into what two basic categories?
Q38. What position data are supplied by 2D search radar?
Q39. Why do 2D air-search radars use relatively low carrier frequencies and low pulse-repetitionrates?
Q40. Why is the range capability of 3D radar usually less than the range of 2D radar?
Q41. Fire-control tracking radar most often radiates what type of beam?
Q42. Tracking radar searches a small volume of space during which phase of operation?
Q43. What width is the pulse radiated by fire-control tracking radar?
Q44. Which beam of missile-guidance radar is very wide?
NEETS MODULE 18 CHAPTER 2 RADAR SUBSYSTEMS
Q1. What is the purpose of the synchronizer in a radar system?
Q2. What is the purpose of the majority of circuits in a radar system?
Q3. A self-synchronized radar system obtains timing trigger pulses from what source?
Q4. What type of multivibrator can be used as a radar master oscillator?
Q5. In an externally synchronized radar, what determines the prr of the transmitter?
Q6. In figure 2-1, what causes the initial and final pulses on the receiver output signal?
Q7. What basic circuits meet the requirements of an externally synchronized master oscillator?
Q8. Name a disadvantage of sine-wave oscillator synchronizers
Q9. Which of the basic timing circuits produces sharp trigger pulses directly?
Q10. What are the two basic types of transmitters?
Q11. What controls transmitter pulse width?
Q12. In addition to a flat top, what characteristics must a modulator pulse have?
Q13. What type of modulator is most commonly used in modern radar systems?
Q14. What three types of storage elements most often are used in modulators?
Q15. What characteristic is determined by the time required for a voltage wave to travel from the inputend of an artificial transmission line to the output end and back again?
Q16. What type of tube best meets the requirements of a modulator switching element?
Q17. What modulator element controls the rate at which the storage element charges?
Q18. What is the frequency range of magnetron oscillators?
Q19. What two forms of instability are common in magnetrons?
Q20. What is the effect on magnetron operation if the magnetic field strength is too high?
Q21. What is the typical frequency range about the center frequency of a tunable magnetron?
Q22. What is the primary advantage of power-amplifier transmitters over keyed-oscillatortransmitters?
Q23. In the power amplifier shown in figure 2-10, what two signals are mixed to produce the outputsignal?
Q24. What type of klystron is used as the final stage of a power-amplifier transmitter?
Q25. What transmitter component allows the radiation of a large number of discrete frequencies overa wide band?
Q26. What is the result of pulsing a pulsed rf amplifier when no rf is present?
Q27. What type of switches are used as duplexers?
Q28. What tube in a duplexer has the primary function of disconnecting the receiver?
Q29. How may the tr tube ionization speed be increased?
Q30. The actions of the tr and atr circuits depend on the impedance characteristics of what length oftransmission line?
Q31. During which of the transmit or receive cycles are both the tr and atr tubes of a parallelconnectedduplexer ionized (arcing)?
Q32. In a series-connected duplexer, what tube (tr or atr), if any, fires during the receive cycle?
Q33. To propagate energy down an arm of a hybrid ring duplexer, the two fields at the junction of thearm and the ring must have what phase relationship?
Q34. What is the greatest limiting factor in a receiver’s detectable range?
Q35. What type of receiver is most often used in radar systems?
Q36. What IF frequencies are normally used in radar receivers?
Q37. Which component of the receiver produces the signal that is mixed with the received signal toproduce the IF signal?
Q38. What receiver circuit actually produces the IF frequency?
Q39. The IF amplifiers are connected in what amplifier configuration?
Q40. Which receiver component converts the IF pulses to video pulses?
Q41. Which of the two types of automatic gain control, agc or iagc, is most effective in radar use forthe Navy?
Q42. Immediately after the transmitter fires, stc reduces the receiver gain to what level?
Q43. How does ftc affect receiver gain, if at all?
Q44. What type of target has a fixed phase relationship from one receiving period to the next?
Q45. What signal is used to synchronize the coherent oscillator to a fixed phase relationship with thetransmitted pulse?
Q46. What is the phase relationship between the delayed and undelayed video?
Q47. When a large signal and a small signal are applied to a lin-log amplifier at the same time, whatis the effect on the small signal?
Q48. What happens to the overall gain of a lin-log amplifier as each stage saturates?
Q49. A monopulse receiver has how many separate channels?
Q50. If a target is on the bearing axis of the radiated beam, what is the input to the bearing IFchannel?
Q51. What characteristic of the bearing and elevation output signals determines the direction ofantenna movement?
NEETS 18 CHAPTER 3 RADAR INDICATORS AND ANTENNAS
Q1. What are the three fundamental quantities involved in radar displays?
Q2. What are the required radar inputs for proper indicator operation?
Q3. What coordinates are displayed on an rhi scope?
Q4. What coordinates are presented on a ppi scope?
Q5. What type of deflection is preferred for a crt electron beam?
Q6. Which of the two types of deflection coils (fixed or rotating) is used most often?
Q7. What type of ranging circuit is most often used with a radar that requires extremely accuraterange data?
Q8. The range sweep in a range-gate generator is started at the same time as what other pulse?
Q9. Range-marker generators produce pulses based on what radar constant?
Q10. What radar scope uses a range step for range measurement?
Q11. Which of the two general classes of antennas is most often used with radar?
Q12. The power gain of an antenna is directly related to what other antenna property?
Q13. A parabolic reflector changes a spherical wavefront to what type of wavefront?
Q14. How many major lobes are produced by a paraboloid reflector?
Q15. What type of radiator normally drives a corner reflector?
Q16. The broadside array consists of a flat reflector and what other elements?
Q17. Horn radiators serve what purpose other than being directional radiators?
NEETS MODULE 18 CHAPTER 4 RADAR SYSTEM MAINTENANCE
Q1. The spectrum of a radar transmitter describes what characteristic of the output pulse?
Q2. Where should the transmitter spectrum be located with respect to the receiver response curve?
Q3. The ideal radar spectrum has what relationship to the carrier frequency?
Q4. The display screen of a spectrum analyzer presents a graphic plot of what two signalcharacteristics?
Q5. The peak power of a radar depends on the interrelationship of what other factors?
Q6. Transmitter power readings are most often referenced to what power level?
Q7. A loss of receiver sensitivity has the same effect on range performance as what other loss?
Q8. You determine receiver sensitivity by measuring the power level of what signal?
Q9. When measuring receiver sensitivity, what quantities must you add to the dBm reading obtainedon the signal generator or test set?
Q10. Receiver bandwidth is defined as those frequencies spread between what two points of thereceiver response curve?
Q11. The end of the usefulness of a tr tube is indicated by an increase in what quantity?
Q12. Most shipboard distribution systems use ac power that has what number of phases?
Q13. How is emergency power applied when normal power is lost?
Q14. What device is used to switch power from the normal source to an alternate source for nonvitalusers?
Q15. What procedure should you use when a power input to your equipment is missing?
Q16. What is the normal source of dry air for a radar system?
Q17. What is the major difference between the electronics dry-air branch and the vital service lp airmain?
Q18. What is the air control panel designed to control?
Q19. What type of cooling is used to control ambient room temperature?
Q20. A typical liquid-cooling system is composed of what loops?
Q21. What loop of a cooling system is often supplied by sea water?
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