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This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 351. |
What is the main weakness of the ILS system?(a) Less power(b) Less range(c) More noise(d) Environment sensitivity |
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Answer» Right option is (d) Environment sensitivity Explanation: The main weakness of the ILS system was its sensitivity towards the environmental factors. Since the frequency used by the system is in MHz, it was more susceptible to atmospheric and weather interference. |
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| 352. |
Which of the following is false with respect to Omega systems?(a) Four common transmitted signal frequencies(b) One unique frequency for each station(c) 0.2 sec separation between each of eight transmissions(d) Constant length transmission periods |
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Answer» Right option is (d) Constant length transmission periods Best explanation: The Omega system has variable length transmission periods. This makes it possible for users to synchronize an Omega receiver to the signal format with no additional extra information. |
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| 353. |
Which type of direction finders takes bearings on airborne transmitters and advice the aircraft of its bearing from the ground station?(a) Ground based(b) Airborne direction finders(c) Homing adapters(d) Homing beacon |
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Answer» Correct option is (a) Ground based To elaborate: Ground based direction finders take bearings on airborne transmitters and advice the aircraft of its bearing from the ground station. Such stations can afford the necessary complex equipment, but the operation is cumbersome and time consuming, and requires airborne transmitter and communication link. |
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| 354. |
Which of the following is not a function of the monitoring facility in Omega systems?(a) Monitor performance(b) Acts as relays(c) Provide data to phase synchronize the stations(d) Detect solar terrestrial events |
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Answer» Right choice is (b) Acts as relays The explanation: Each station has a signal monitoring facility that is situated 20 to 50km away from the antenna. These stations perform functions such as monitor signal performance, provide the required data to phase synchronize the stations, and detecting solar terrestrial events that cause shifts in the propagated signal phase. |
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| 355. |
The method in which the user’s receiver and the reference station are assumed not to be synchronized in time is called as _______(a) Redundancy method(b) Pseudoranging(c) Integrity method(d) Differential method |
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Answer» Correct option is (b) Pseudoranging Easiest explanation: In this method, the user’s receiver and the reference station are assumed not to be synchronized in time. By measuring several such pseudoranges, the user’s three dimensional position and its time offset can be determined. |
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| 356. |
The transmitter-receiver combination in the satellite is known as a _______(a) Relay(b) Repeater(c) Transponder(d) Duplexer |
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Answer» Right answer is (c) Transponder Explanation: The transmitter-receiver combination in the satellite is known as a transponder. The basic functions of a transponder are amplification and frequency translation. The reason for frequency translation is that the transponder cannot transmit and receive on the same frequency. |
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| 357. |
What is the process of ensuring that the receiver works on ground waves?(a) PGTR identification(b) ECD(c) HCG(d) TOPCO |
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Answer» Right answer is (a) PGTR identification The best explanation: PGTR or Pulse group time reference identification is the process of ensuring that the receiver is operating on the ground wave of the signal. The basic principle behind it is that ground waves travel faster than sky ways. |
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| 358. |
What is it called when the noise is present in the transmission line but gets canceled at the receiver?(a) Cancellation mode(b) Common mode cancellation(c) Common mode rejection(d) Rectification |
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Answer» Right answer is (c) Common mode rejection To elaborate: When the noise affects the transmission, its effect is on both the wires but since they are 180° out of phase when the signal reaches the receiver the noise gets cancelled out. This is called common-mode rejection, and noise reduction can be as great as 60 to 70 dB. |
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| 359. |
What is TDOP?(a) Time Dilution of pseudorange(b) Time Dilution of position(c) Time Dilution of pressure(d) Time Distortion of position |
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Answer» Right choice is (b) Time Dilution of position The best explanation: TDOP is the Time Dilution of position. It is the contribution of clock error to the error in pseudorange. |
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| 360. |
The factor by which a receiver fails to reach the theoretical internal noise limit is known as ________(a) Noise factor(b) Noise(c) Coefficient of noise(d) Noise figure |
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Answer» The correct answer is (d) Noise figure For explanation: The factor by which a receiver fails to reach the theoretical internal noise limit is often expressed as a ratio, in decibels, and is known as the noise figure. It can also be described as the ratio between the noise power output of a practical receiver and the noise power output of an ideal receiver. |
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| 361. |
The ratio of terminating impedance to the power density of the incident wave is called as?(a) Maximum effective aperture(b) Maximum allowable power(c) Directivity(d) Gain |
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Answer» Right option is (a) Maximum effective aperture To explain I would say: Maximum effective aperture is defined as the ratio of terminating impedance to the power density of the incident wave. It is also called the effective area of an antenna and is given by Dλ/4π. |
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| 362. |
The impedance of a line is zero when ___________(a) It acts as inductor(b) It acts as capacitor(c) It acts as a resistor(d) Series resonant circuit |
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Answer» The correct choice is (d) Series resonant circuit Easy explanation: If the line acts as a series resonant circuit, its impedance is zero. If the line is of such a length that it acts as a parallel resonant circuit, its impedance is near infinity. If the line is some intermediate length, it is reactive. |
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| 363. |
When does an open transmission line look like an inductor to the generator?(a) Length is one quarter wavelength(b) Length is between one quarter and one half of wavelength(c) Length is more the one half of the wavelength(d) At all times |
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Answer» The correct answer is (b) Length is between one quarter and one half of wavelength To explain I would say: If the open transmission line is less than one-quarter wavelength, the generator sees a capacitance. If the line is between one-quarter and one-half wavelength, the generator sees an inductance. These characteristics repeat for lines that are some multiple of one-quarter or one-half wavelengths. |
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| 364. |
When a shorted line does looks like a series resonant circuit to the generator?(a) Length of line is one quarter wavelength(b) Length of line is one half wave lengths(c) Sorted line(d) Open line |
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Answer» Right answer is (b) Length of line is one half wave lengths The best explanation: When the length of the transmission line is one half of the wavelength, a standing wave pattern is produced where the current and voltage at the generator and the end of the transmission line is same. In this case, the line looks like a series resonant circuit to the generator. |
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| 365. |
In two mode RLGs, only linearly polarized modes can be resonant in the cavity.(a) True(b) FalseThe question was asked during a job interview.This interesting question is from Gyroscopes topic in section Satellite Radio Navigation & Inertial Navigation of Avionics |
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Answer» Right answer is (a) True To elaborate: Two mode RLGs are planar by design so that only linearly polarized modes can be resonant in the cavity. Suppression of one of the two modes of polarization ensures stable operation. |
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| 366. |
What happens when a vertical or horizontal polarized antenna receives a circular polarized wave?(a) Gain increases(b) Signal strength increases(c) Signal strength reduces(d) Cannot receive circular polarized waves |
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Answer» The correct option is (c) Signal strength reduces Explanation: A vertical or horizontal antenna can receive circular polarized signals, but the signal strength is reduced. When circular polarization is used at both transmitter and receiver, both must use either left- or right-hand polarization if the signal is to be received. |
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