Description : What is a selective fading effect? A. A fading effect caused by small changes in beam heading at the receiving station. B. A fading effect caused by phase differences between radio wave ... station D. A fading effect caused by time differences between the receiving and transmitting stations.
Last Answer : B. A fading effect caused by phase differences between radio wave components of the same transmission, as experienced at the receiving station.
Description : What is the major cause of selective fading? A. Small changes in the beam heading at the receiving station. B. Large changes in the height of the ionosphere, as experience at the ... Phase differences between radio wave components of the same transmission, as experienced at the receiving station.
Last Answer : D. Phase differences between radio wave components of the same transmission, as experienced at the receiving station.
Description : Refers to an effect of selective fading. A. A fading effect caused by phase differences between radio wave components of the same transmission, as experienced at the receiving station. B. A fading ... caused by large changes in the height of the ionosphere, as experienced at the receiving station.
Last Answer : A. A fading effect caused by phase differences between radio wave components of the same transmission, as experienced at the receiving station.
Description : Loss due to the diffraction of light when it strikes on the irregularities formed during the manufacturing process of the fiber optics. A. Absorption loss B. Attenuation C. Bending loss D. Rayleigh scattering loss
Last Answer : D. Rayleigh scattering loss
Description : The dominant loss mechanisms in silica fiber are ∙ a. Absorption and radiation losses ∙ b. Absorption and Rayleigh scattering ∙ c. Coupling and radiation losses ∙ d. Radiation and modal dispersion
Last Answer : b. Absorption and Rayleigh scattering
Description : Anion gap is increased in (A) Renal tubular acidosis (B) Metabolic acidosis resulting from diarrhoea (C) Metabolic acidosis resulting from intestinal obstruction (D) Diabetic ketoacidosis
Last Answer : Answer : B
Description : The best solution to fading is _____. A. space diversity B. frequency diversity C. polarization diversity D. wavelength diversity
Last Answer : A. space diversity
Description : What do you call the service area of a standard AM broadcast where fading is allowed but not objectionable co-channel interference? A. Experimental B. Secondary C. Tertiary D. Primary
Last Answer : B. Secondary
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 : 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 : When the clearance above the obstruction is equal to the radii of even Fresnel zone at the point of reflection the RSL A. remains the same B. is above threshold C. is decreased D. is increased
Last Answer : C. is decreased
Description : What is one of the major reasons for the fading of radio waves which have been reflected from a surface?
Last Answer : Shifting in the phase relationships of the wave.
Description : It is an average power of a radio transmitter supplied to the antenna transmission line taken during a long sufficient interval of time and compared with the lowest frequency encountered in the modulation ... operating conditions. A. Carrier power B. Rated power C. Mean power D. Peak envelop power
Last Answer : C. Mean power
Description : ECE Board Exam March 1996 The K-factor under normal atmospheric conditions in a microwave radio data profile calculation is equal to ___________. A. 2/3 B. 0 C. 4/3 D. Infinity
Last Answer : C. 4/3
Description : Noise occurring in the presence of signal resulting from a mismatch between the exact value of an analog signal and the closet available quantizing step in a digital coder. A. Quantizing noise B. Thermal noise C. Impulse noise D. Crosstalk
Last Answer : A. Quantizing noise
Description : One of the following is a possible cause for a slow drift of frequency in a self-exited transmitter oscillator circuits resulting to a poor frequency stability. A. Loose shielding B. ... capacitor in the oscillator C. Poor soldered connections D. Faulty capacitor, resistor, tubes or resistors
Last Answer : B. Heating of capacitor in the oscillator
Description : One of the following is a possible cause of an abrupt frequency variation in a self exited transmitter oscillator circuits resulting to a poor frequency stability to hold a constant frequency ... capacitor in the oscillator D. Loose connections in the oscillator, amplifier, or antenna circuits.
Last Answer : D. Loose connections in the oscillator, amplifier, or antenna circuits.
Description : Which of the following is one of the possible causes for a slow drift of frequency in a self exited transmitter oscillator circuits resulting to a poor frequency stability? A. Poor soldered connections ... , or antenna circuits D. DC and RF heating of resistors, causing then to change values.
Last Answer : D. DC and RF heating of resistors, causing then to change values.
Description : Which of the following is an example of alien species invading a new ecosystem resulting in biodiversity losses ?
Last Answer : Which of the following is an example of alien species invading a new ecosystem resulting in biodiversity ... into Indian rivers D. All of the above
Description : A matrix which shows the gains and losses resulting from moves and counter moves is called.................................. a. Cost matrix b. Pay off matrix c. Both a and b d. None of these
Last Answer : b. Pay off matrix
Description : For a shortened vertical antenna, where should a loading coil be placed to minimize losses and produce the most effective performance? A. As low as possible on the vertical radiator B. Near the center of the vertical radiator C. As close to the transmitter as possible D. At a voltage node
Last Answer : B. Near the center of the vertical radiator
Description : The advantage of using top loading in a shortened HF vertical antenna is A. lower quality factor B. greater structural strength C. higher losses D. improved radiation efficiency
Last Answer : D. improved radiation efficiency
Description : A satellite transmitter operates at 4GHz with an antenna gain of 4dBi. The receiver 40000 km away has an antenna gain of 50 dBi. If the transmitter has a power of 8 W, find (ignoring feedline losses and mismatch) the EIRP in dBW. A. 50 B. 69 C. 49 D. 30
Last Answer : C. 49
Description : What is meant by the term radiation resistance for an antenna? A. The resistance in the trap coils to received signal B. An equivalent resistance that would dissipate the same amount of power as ... antenna C. The specific impedance of the antenna D. Losses in the antenna elements and feed line
Last Answer : B. An equivalent resistance that would dissipate the same amount of power as that radiated from an antenna
Description : What is meant by antenna gain? A. The final amplifier gain minus the transmission line losses (including any phasing lines present) B. The ratio of the amount of power produced by the antenna ... D. The numeric ratio relating the radiated signal strength of an antenna to that of another antenna
Last Answer : D. The numeric ratio relating the radiated signal strength of an antenna to that of another antenna
Description : _____ is an antenna made up of a number of full wavelengths A. Elementary doublet B. Log-periodic C. Long wire D. Whip
Last Answer : C. Long wire
Description : One of the following is very useful as a multiband HF receiving antenna. A. Parabolic antenna B. Elementary doublet C. Log-periodic D. Square loop
Last Answer : C. Log-periodic
Description : ______ is an antenna array which is highly directional at right angles to the plane of the array? A. Broadside array B. End-fire array C. Turnstile array D. Log-periodic array
Last Answer : A. Broadside array
Description : All elements in a beam _____ antennas are in line A. collinear B. yagi C. broadside array D. log-periodic
Last Answer : A. collinear
Description : Modulation in which the modulated wave is always present. A. Carrier modulation B. Front-end C. Continuous modulation D. Log-periodic modulation
Last Answer : C. Continuous modulation
Description : Two wires that are bent 90 degrees apart. A. Hertz B. Dipole C. Log-periodic D. Rhomic
Last Answer : B. Dipole
Description : Listing of the date and time events, programs , equipment, test, malfunctions and corrections in communication system. A. File B. Documentation C. Reporting D. Log
Last Answer : D. Log
Description : Sound intensity level is ________. A. 10 log I/I(ref) B. 10 log I(ref)/I C. 30 log I/I(ref) D. 20 log I/I(ref)
Last Answer : A. 10 log I/I(ref)
Description : A microwave communications system space loss calculation formula is A. 92.4 + 10 log f +20 log d B. 94.2 + 10 log f +20 log d C. 92.4 + 20 log f +20 log d D. 94.2 + 20 log f +20 log d
Last Answer : C. 92.4 + 20 log f +20 log d
Description : A type of array antenna which consists of one half-wave driven dipole, one reflector and one director A. Hertzian dipole B. Yagi-uda C. Broadside collinear D. Log periodic dipole array
Last Answer : B. Yagi-uda
Description : It consists of a number of dipoles of equal size, equally spaced along a straight line with all dipoles fed in the same phase from the same source. A. Log-periodic antenna B. Yagi antenna C. End-fire array D. Broadside array
Last Answer : D. Broadside array
Description : List the applications of Log amplifiers:
Last Answer : 1.Analog computation may require functions such as lnx, log x, sin hx etc. These functions can be performed by log amplifiers 2.Log amplifier can perform direct dB display on digital voltmeter and spectrum analyzer 3.Log amplifier can be used to compress the dynamic range of a signal
Description : Under normal condition, a single fiber should not be used for a two-way communication mainly because of ∙ a. Loss ∙ b. Fading ∙ c. Noise ∙ d. Attenuation
Last Answer : ∙ c. Noise
Description : Satellite system or part of a satellite system, consisting of only one satellite and the operating earth station. A. Satellite system B. Satellite network C. Space system D. Multi-satellite link
Last Answer : B. Satellite network
Description : Isoxsuprine increases limb blood flow in normal individuals, but is of limited efficacy in Buerger's disease, because in this disease: A. Vasodilator β adrenoceptors are deficient B. There is loss ... affected limb is reduced by organic obstruction D. The drug is not delivered to the affected site
Last Answer : C. Blood flow to the affected limb is reduced by organic obstruction
Description : When insulation failure produces a low resistance current path between two conductors, the resulting condition is known as ____________. A. an open B. a short circuit C. a ground D. a surge
Last Answer : Answer: B
Description : Which among the following is correct about goals in cryptography: a) Confidentiality - Only an authorized recipient should be able to extract the contents of the message from its encrypted form. Resulting from steps ... not be able to deny sending the message e) None of These f) All of the Above
Last Answer : f) All of the Above
Description : The sky appears blue due to – (1) Rayleigh scattering (2) Mie scattering (3) Back scattering (4) None of the above
Last Answer : (1) Rayleigh scattering Explanation: The blue colour of the sky is due to Rayleigh scattering. As light moves through the atmosphere, most of the longer wavelengths pass straight through. Little ... absorbed blue light is then radiated in different directions. It gets scattered all around the sky.
Description : Lord Rayleigh and William Ramsay got Nobel Prizefor the discovery of Argon in?
Last Answer : 1904
Description : Rayleigh equation applies to __________ distillation. (A) Differential (B) Flash (C) Equilibrium (D) Molecular
Last Answer : (A) Differential
Description : The equation, (h.D/K) is called the __________ number. (A) Nusselt (B) Peclet (C) Rayleigh (D) Grashoff
Last Answer : (A) Nusselt
Description : The first critical speed of an automobile running on a sinusoidal road is calculated by (modeling it as a single degree of freedom system) A Resonance B Approximation C Superposition D Rayleigh quotient
Last Answer : A Resonance
Description : The first critical speed of an automobile running on a sinusoidal road is calculated by (modeling it as a single degree of freedom system) a) Resonance b) Approximation c) Superposition d) Rayleigh quotient
Last Answer : a) Resonance