Description : Which of the following systems is not used in radio detection and ranging? A. Frequency shift B. Frequency modulation C. Pulse radar D. Amplitude modulation
Last Answer : D. Amplitude modulation
Description : Which of the following sensor work based on radio detection and ranging? A : Sonar B : Radar C : Intertial D : Biosensor
Last Answer : B : Radar
Description : Which of the following is not a common microwave application? A. Radar B. Data transmission C. Space communications D. Mobile radio
Last Answer : D. Mobile radio
Description : Which of the following sensor work based on sound navigation ranging? A : Sonar B : Radar C : Intertial D : Biosensor
Last Answer : A : Sonar
Description : What type of ranging circuit is most often used with a radar that requires extremely accurate range data?
Last Answer : Range gate or range step.
Description : Ranging in chain survey means (A) Looking at an isolated point not on the line (B) Establishing an intermediate point on the line (C) Determining the distance between end points (D) Determining the offset distance
Last Answer : (B) Establishing an intermediate point on the line
Description : A star rating, ranging from ________ in the asending order of energy efficiency.imp A) 1 to 4. C) 1 to 5 B) 1 to 6. D) 1 to 10
Last Answer : 1 to 5
Description : For a space wave transmission, the radio horizon distance of a receiving antenna with a height of 64 meters is approximately A. 8 km B. 32 km C. 64 km D. 256 km
Last Answer : B. 32 km
Description : What phenomenon causes the radio-path horizon distance to exceed the geometric horizon? A. Diffraction B. Ducting C. Reflection D. Refraction
Last Answer : D. Refraction
Description : A radio communications link is to be established via the ionosphere. The maximum virtual height of the layer is 100 km at the midpoint of the path and the critical frequency is 2 MHz. The distance between stations is 600 ... optimum working frequency? A. 6.32 MHz B. 2.1 MHz C. 5.4 MHz D. 1.8 MHz
Last Answer : C. 5.4 MHz
Description : In cellular system, _____ defines the geographic distance that is required between cells using identical frequencies in order to avoid interference between the radio transmissions at these cells. A. frequency-reuse ratio B. distance-to-reuse ratio (D/R) C. reuse format plan ratio D. reuse factor
Last Answer : B. distance-to-reuse ratio (D/R)
Description : For a space wave transmission, the radio horizon distance of a transmitting antenna with a height of 100 meters is approximately: A. 10 km B. 40 km C. 100 km D. 400 km
Last Answer : B. 40 km
Description : What phenomenon causes the radio-path horizon distance to exceed the geometric horizon? A. E-layer skip. B. D-layer skip. C. Auroral skip. D. Radio waves may be bent.
Last Answer : D. Radio waves may be bent.
Description : In radio signal emission designation, the fifth symbol means A. Details of signals B. Type of information transmitted C. Nature of multiplexing D. Nature of signal modulating the main carrier
Last Answer : C. Nature of multiplexing
Description : ____ is defined as any radiation of energy by means of electromagnetic wave. A. Emission B. Radiation C. Radio D. Broadcasting
Last Answer : A. Emission
Description : ________ dispersion is caused by the difference in the propagation times of light rays that take different paths down a fiber. a. Material dispersion b. Wavelength dispersion c. Modal dispersion d. Delay dispersion
Last Answer : c. Modal dispersion
Description : What is the propagation delay when a signal is transmitter by an earth station to a geosynchronous satellite about 38,500 km above earth’s equator and then received by the same earth station? A. 256 msec B. 128 msec C. 300 msec D. 400 msec
Last Answer : A. 256 msec
Description : The round-trip propagation delay between two earth stations through a geosynchronous satellite is A. 500 to 600 ms B. 300 to 400 ms C. 600 to 700 ms D. 400 to 500 ms
Last Answer : A. 500 to 600 ms
Description : The total propagation delay time from transmission to reception of signals from a ground transmitter to ground receiver with angle of elevation at 10 degrees respectively is A. 273 ms B. 239 ms C. 275 ms D. 260 ms
Last Answer : A. 273 ms
Description : The maximum propagation delay of a geostationary satellite is A. 278 ms B. 239 ms C. 300 ms D. 250 ms
Last Answer : A. 278 ms
Description : What is the delay time for satellite transmissions from earth transmitter to earth receiver? A. 0.5 s B. 1s C. 5 ms D. 0.25 s
Last Answer : A. 0.5 s
Description : What is the delay time for satellite transmission from earth transmitter to earth receiver? A. 0.5 s B. 1.0 s C. 5 ms D. 0.25 ms
Description : What is the minimum propagation delay of a geostationary satellite? A. 278 ms B. 239 ms C. 300 ms D. 600 ms
Last Answer : B. 239 ms
Description : What is the time delay introduced by a 75-ft coaxial cable with a dielectric constant of 2.3? A. 1.54 ns B. 11.5 ns C. 115.6 ns D. 1156 ns
Last Answer : C. 115.6 ns
Description : What do you call a transmission line used specifically for the purpose of achieving delay? A. Delay line B. Flat line C. Resonant line D. Non-resonant line
Last Answer : A. Delay line
Description : What is transit time (time delay) of a 50-ft length transmission line of the above problem? A. 50 ns B. 100 ns C. 75 ns D. 65 ns
Last Answer : C. 75 ns
Description : What do you call the phenomenon in digital circuits that describe the duration of time a digital signal passes a circuit? A. Transmission time B. Elapsed time C. Propagation delay D. Travel delay
Last Answer : C. Propagation delay
Description : What is the phase delay of an 800 Hz voice signal if the phase shift is 15 degrees? A. 1.25 µsec B. 52 µsec C. 83.33 µsec D. 26 µsec
Last Answer : B. 52 µsec
Description : How would one squeeze more channels of communication into TDM frames of standard length? A. Shorten the time delay for each channel B. Raise the amplitude C. Add modulators D. Remove the synchronizing pulses
Last Answer : A. Shorten the time delay for each channel
Description : In accordance with Coast Guard Regulations (46 CFR), a circuit breaker located in the machinery space and installed in a 440V AC system must _____________. A. be dependent upon mechanical ... the maximum asymmetrical shortcircuit current available at the point of application D. all of the above
Last Answer : Answer: C
Description : . If the power distribution system shown in figure 2-22 uses selective tripping, what is the time delay rating for each of the circuit breakers shown?
Last Answer : CB1-long time delay; CB2, CB3-short time delay; CB4 through
Description : What do you call the random noise seen on radar display screen? A. Impulse noise B. Atmospheric noise C. Grass D. Johnson noise
Last Answer : C. Grass
Description : What determines the ability of radar to determine the bearing to a target? A. Speed of light B. Speed of target C. Antenna directivity D. Frequency of signal
Last Answer : C. Antenna directivity
Description : What is the most commonly used intermediate frequency of radar receivers? A. 40 MHz B. 60 MHz C. 70 MHz D. 30 MHz
Last Answer : D. 30 MHz
Description : What instrument normally measures the virtual height of ionosphere? A. Ionosonde B. Altimeter C. Field meter D. Radar
Last Answer : A. Ionosonde
Description : For navigation as well as marine and aeronautical communications and radar, ____ band is used. A. L B. K C. S D. J
Last Answer : A. L
Description : Which band of frequencies used by military for its satellites and radar? A. C band B. X band C. L band D. P band
Last Answer : B. X band
Description : Low-power radar uses A. RIMPATT B. TRAPATT C. Magnetron D. IMPATT
Last Answer : D. IMPATT
Description : How many removal examination (s) will be given to an examinee who obtains a passing rating in the majority of the subjects but obtains a rating in the other subject (s) below seventy percent (70%) but not lower than sixty percent (60%)? A. 1 B. 3 C. 2 D. Unlimited
Last Answer : A. 1
Description : The smaller the f rating, the _____ light that lens can take in. A. More B. Intense C. Less D. Same
Last Answer : A. More
Description : Ranging is an operation of (A) Reconnaissance (B) Judging the distance (C) Determination of slope (D) Establishing intermediate points between terminals
Last Answer : (D) Establishing intermediate points between terminals
Description : The most common device used for detection in radio receivers is (A)amplifier (B) triode (C) diode (D) transistor
Last Answer : The most common device used for detection in radio receivers is diode