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Free download in PDF Microwave Communication General Knowledge Multiple Choice Questions(MCQs) & Answers for competitive exams. These short objective type questions with answers are very important for Board exams as well as competitive exams. These short solved questions or quizzes are provided by Gkseries.
(1)
The highest frequency which a conventional vacuum-tube oscillator can generate is not limited by the
[A]
Electron transit time
[B]
Distributed lead inductance
[C]
Inter-electrode capacitance
[D]
Degree of emission from the cathode
Answer: Degree of emission from the cathode
(2)
Microwave frequencies are normally regarded as those in the range of
[A]
1 to 500 MHz
[B]
1000 to 10,000 GHz
[C]
1 to 100 GHz
[D]
10 to 1000 GHz
(3)
Which of the following is used as an oscillator device in the SHF band?
[A]
Thyratron tube
[B]
Tunnel diode
[C]
Klystron tube
[D]
Both B and C
(4)
What is the purpose of the electromagnetic field which surrounds a traveling-wave tube?
[A]
To accelerate the electron
[B]
To velocity modulate the electron beam
[C]
To keep the electrons from spreading out
[D]
To slow down the signal on the helix
Answer: To keep the electrons from spreading out
(5)
A traveling-wave tube (TWT) amplifies by virtue of
[A]
The absorption of energy by the signal from an electron stream
[B]
The effect of an external magnetic field
[C]
The energy contained the cavity resonators
[D]
The energy liberated form the collector
Answer: The absorption of energy by the signal from an electron stream
(6)
A high-power microwave pulse of the order of megawatts can be generated by a
[A]
traveling-wave tube
[B]
magnetron
[C]
reflex klystron
[D]
Gunn diode
(7)
Coupling into and out of a traveling-wave tube can be accompanied by a
[A]
Direct coax-helix match
[B]
Cavity match
[C]
Waveguide match
[D]
All of the above
(8)
At what position is the input signal inserted into a traveling-wave tube?
[A]
At the cathode end of the helix
[B]
At the collector
[C]
At the collector end of the helix
[D]
At the control grid of the electron gun
Answer: At the cathode end of the helix
(9)
The cavity resonator
[A]
Is equivalent to an LC resonant circuit
[B]
In a reflect klystron has its output taken from the reflector plate
[C]
Produces a frequency which is independent of the cavity size.
[D]
Has a low Q factor for narrow operation.
Answer: Is equivalent to an LC resonant circuit
(10)
A shipboard equipment which measures the distance between the ship’s bottom and the ocean floor.
[A]
Fathometer
[B]
Echosounder
[C]
LORAN
[D]
SONAR
(11)
In microwave transmission using digital radio, what causes most intersymbol interference?
[A]
Delayed spreading
[B]
Rayleigh fading
[C]
Random Doppler shift
[D]
Slow fading
Answer: Delayed spreading
(12)
Which causes multipath or frequency-selective fading?
[A]
Small reflector
[B]
Nearer reflector
[C]
Further reflector
[D]
Large reflector
(13)
Which of the reception problems below that is not due to multipath?
[A]
Delayed spreading
[B]
Rayleigh fading
[C]
Random Doppler shift
[D]
Slow fading
(14)
What do you call an attenuation that occurs over many different wavelengths of the carrier?
[A]
Rayleigh fading
[B]
Rician fading
[C]
Wavelength fading
[D]
Slow fading
(15)
Theoretically electromagnetic radiation field strength varies in inverse proportion to the square of the distance, but when atmospheric attenuation effects and the absorption of the terrain are taken into account the attenuation can be as high as the inverse _______ power of the distance.
[A]
Third
[B]
Fourth
[C]
Fifth
[D]
Sixth
(16)
Rainfall is an important factor for fading of radio waves at frequencies above
[A]
10 GHz
[B]
100 GHz
[C]
1 GHz
[D]
100 MHz
(17)
the antenna separations (in meters) required for optimum operation of a space diversity system can be calculated from:
where R = effective earth radius (m) and L = path length (m)
[A]
S = 2λR/L
[B]
S = 3λR/L
[C]
S = λR/RL
[D]
S = λR/L
(18)
If k-factor is greater than 1, the array beam is bent
[A]
Away from the earth
[B]
towards the ionosphere,
[C]
towards the earth
[D]
towards the outer space
Answer: towards the earth
(19)
Calculate the effective earth’s radius if the surface refractivity is 301.
[A]
8493 km
[B]
8493 mmi
[C]
6370 km
[D]
6370 mi
(20)
__________ is the progressive decrease of signal strength with increasing distance.
[A]
Radiation
[B]
Attenuation
[C]
Modulation
[D]
Propagation
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