Description : The rhombic antenna is primarily used for A. ground wave propagation B. space wave propagation C. ionosphere scatter propagation D. sky wave propagation
Last Answer : D. sky wave propagation
Description : The decimetric wave is using what method of propagation? A. Ground wave B. Space wave C. Sky wave D. Tropospheric wave
Last Answer : B. Space wave
Description : Which of the following is not one of the natural ways a radio wave may travel from transmitter to receiver? A. Ground wave B. Micro wave C. Sky wave D. Space wave
Last Answer : B. Micro wave
Description : ECE Board Exam March 1996 When the transmitting and receiving antennas are in line-of-sight of each other, the mode of propagation is ________ wave. A. space or direct B. ground C. surface D. sky
Last Answer : A. space or direct
Description : Indicate the false statement. A. Industrial noise is usually of the impulse type B. Static is caused by lightning discharges in thunderstorms and other natural electric disturbances occurring in the ... another source of man-made noise D. Flourescent lights are another source of man-made noise
Last Answer : C. Distant stars are another source of man-made noise
Description : Transmission lines are either balanced or unbalanced with respect to _________. A. negative terminal B. input C. ground D. positive terminal
Last Answer : C. ground
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 : 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 : The total space loss of transmission and reception for two ground stations with uplink frequency 8GHz and a downlink of 6 GHz with angle of elevations of 3˚ and 7˚ A respectively is A. 403 dB B. 100 dB C. 20 dB D. 215 dB
Last Answer : A. 403 dB
Description : Which propagation method is known as special case of skywave? A. Space wave B. Troposcatter C. Ground wave D. Direct wave
Last Answer : B. Troposcatter
Description : Space diversity transmission means transmitting and receiving on _______. A. Two or more antennas operating on two different frequencies B. Two or more identical frequencies C. Two or more antennas operating on the same frequency D. Two or more different frequency
Last Answer : C. Two or more antennas operating on the same frequency
Description : What noise is a transient short-duration disturbance distributed essentially uniformly over the useful passband of a transmission system? A. Flicker noise B. Transit-time noise C. Shot noise D. Impulse noise
Last Answer : D. Impulse noise
Description : What is the effect in over modulated amplitude modulated radio broadcasting transmission? A. Interference to adjacent channel B. Higher fidelity C. Increase noise D. Higher audio signal
Last Answer : A. Interference to adjacent channel
Description : Compare ground wave propagation. Sky wave propagation and space wave propagation.
Last Answer : Sr. N o Parameter Ground Wave Propagation Sky Wave Propagation Space wave Propagation 1 Frequency Range 30 kHz to 3 MHz 3 MHz to 30 MHz frequencies above 30 MHz 2 ... These waves have line of sight propagation, ... 6 Fading Problem less Severe Less
Description : Which of the following layers of the ionosphere has no effect on sky wave propagation during daytime? A. D B. E C. F1 D. F2
Last Answer : A. D
Description : Tropospheric scatter is a method of sky wave propagation for which of the following frequency bands? A. 300 kHz to 3 MHz B. 3 MHz to 30 MHz C. 30 MHz to 300 MHz D. 300 MHz to 3 GHz
Last Answer : D. 300 MHz to 3 GHz
Description : To obtain the most reliable sky wave propagation the ____ should be used. A. Lowest useable frequency (LUF). B. Maximum useable frequency (MUF). C. Optimum useable frequency (OUF). D. Critical frequency
Last Answer : C. Optimum useable frequency (OUF).
Description : Which if the following layers of the ionosphere has no effect on sky wave propagation during the hours of darkness? A. D B. E C. F1 D. F2
Description : Which of the following frequency bands is best suited for sky wave propagation? A. 30 to 300 kHz B. 3 MHz to 30 MHz C. 30 MHz to 300 MHz D. 3 GHz to 30 GHz
Last Answer : B. 3 MHz to 30 MHz
Description : The layer of atmosphere used for radio-wave transmission is (1) chromosphere (2) troposphere (3) ionosphere (4) stratosphere
Last Answer : ionosphere
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 : Transmission of printed material over telephone lines. A. Video text B. Facsimile C. Encoding D. Xerox copy
Last Answer : B. Facsimile
Description : The antenna efficiency of an HF grounded vertical antenna can be made comparable to that of a half-wave antenna A. By installing a good ground radial system B. By isolating the coax shield from ground C. By shortening the vertical D. By lengthening the vertical
Last Answer : A. By installing a good ground radial system
Description : How can the antenna efficiency of an HF grounded vertical antenna be made comparable to that of a half-wave antenna? A. By lengthening the vertical B. By installing a good ground radial system C. By shortening the vertical D. By isolating the coax shield from ground
Last Answer : B. By installing a good ground radial system
Description : Where is the noise generated that primarily determines the signal-to-noise ratio in a VHF (150MHz) marine-band receiver? A. Man-made noise B. In the atmosphere C. In the receiver front end D. In the ionosphere
Last Answer : C. In the receiver front end
Description : Strong interference from one particular station can be eliminated by the use of A. noise limiters B. squelch circuits C. negative feedback D. wave traps in the antenna circuitry
Last Answer : D. wave traps in the antenna circuitry
Description : Sources of impulse noise induced in communication channels. A. Erroneous digital coding bit caused by an error on a transmission facility B. Transients due to relay operation C. Crosstalk from dc signaling systems D. All of these
Last Answer : D. All of these
Description : Which causes a quantization noise in PCM system? A. Serial transmission errors B. The approximation of the quantized signal C. The synchronization between encoder and decoder D. Binary coding techniques
Last Answer : B. The approximation of the quantized signal
Last Answer : The approximation of the quantized signal
Description : Quantization noise is caused by A. binary coding techniques B. serial transmission errors C. the synchronization between encoder and decoder D. the approximation of the quantized signal
Last Answer : D. the approximation of the quantized signal
Description : External noise fields are measured in terms of _______. A. rms values B. dc values C. average values D. peak values
Last Answer : D. peak values
Description : _______ is more prevalent in analog signals that have steep slopes or whose amplitudes vary rapidly. A. Peak limiting B. Quantization noise C. Granular noise D. Slope overload
Last Answer : D. Slope overload
Description : Indicate the false statement. A. HF mixer are generally noisier than HF amplifiers. B. Impulse noise voltage is dependent on bandwidth C. Thermal noise is independent of the frequency at which is measured. D. Industrial noise is usually of the impulse type.
Last Answer : B. Impulse noise voltage is dependent on bandwidth
Description : What do you call the noise coming from the sun and stars? A. Black-body noise B. Space noise C. Galactic noise D. All of these
Last Answer : B. Space noise
Description : What noise is observable at frequencies in the range from about 8 MHz to somewhat 1.5 GHz? A. Industrial noise B. Atmospheric noise C. Space noise D. Shot noise
Last Answer : C. Space noise
Description : What noise type is observable between 8 MHz to somewhat above 1.43 GHz or up to 1.5 GHz? A. Solar noise B. Space noise C. Galactic noise D. Cosmic noise
Description : It is useful to refer to an isotropic radiator. A. when comparing the gains of directional antennas B. when testing a transmission line for standing wave ratio C. when (in the northern hemisphere) directing the transmission D. when using a dummy load to tune a transmitter
Last Answer : A. when comparing the gains of directional antennas
Description : Which of the following characterizes a properly terminated transmission line? A. The line loss is minimum. B. The standing wave ratio is minimum. C. The input impedance is twice the load impedance. D. The standing wave ratio is one.
Last Answer : D. The standing wave ratio is one.
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 : When is it useful to refer to an isotropic radiator? A. When comparing the gains of directional antennas B. When testing a transmission line for standing wave ratio C. When (in the northern ... ) directing the transmission in a southerly direction D. When using a dummy load to tune a transmitter
Last Answer : A. When comparing the gains of directional antennas
Description : What type of transmission is radiated from an aircraft’s radio altimeter antenna? A. An amplitude modulated continuous wave B. A pulse position modulated UHF signal C. A differential phase shift keyed UHF signal D. A frequency modulated continuous wave
Last Answer : D. A frequency modulated continuous wave
Description : What is the meaning of the term velocity factor of a transmission line? A. The ratio of the characteristic impedance of the line to the terminating impedance B. The index of shielding for coaxial ... The velocity of the wave on the transmission line divided by the velocity of light in a vacuum.
Last Answer : D. The velocity of the wave on the transmission line divided by the velocity of light in a vacuum.
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 : What is the meaning of the term velocity factor of a transmission line? A. The index of shielding for coaxial cable B. The velocity of the wave on the transmission line multiplied by the velocity of ... The velocity of the wave on the transmission line divided by the velocity of light in a vacuum
Last Answer : D. The velocity of the wave on the transmission line divided by the velocity of light in a vacuum
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 : The standing wave ratio is equal to ________ if the load is properly matched with the transmission line. A. 1 B. 50 C. 10 D. 2
Last Answer : A. 1
Description : The velocity factor in transmission lines vary from ___ to ___. A. 0.6 to 0.8 B. 0.3 to 0.5 C.0.5 to 0.9 D. 0.8 to 0.9
Last Answer : C.0.5 to 0.9
Description : Transmission lines when connected to antenna have A. capacitive load B. resistive load whose resistance is less than characteristics impedance C. resistive load at the resonant frequency D. resistive load whose resistance is greater than the characteristic impedance of the line
Last Answer : C. resistive load at the resonant frequency
Description : ECE Board Exam March 1996 What is the transmission rate of a system for transmitting the output of a microcomputer to a line printer operating at a speed of 30 lines/minute? Assume that the line printer has 8 bits ... and prints out 80 characters/line. A. 800 bps B. 400 bps C. 320 bps D. 640 bps
Last Answer : C. 320 bps
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