Tech Arsenal 1/Tech Arsenal (Arsenal Computer).ISO/tek-20/extra.zip/EXT4.DAT

Text File | 1992-01-11 | 17KB | 438 lines

147C-3.2 C 3-12 5,000 miles
What is the maximum range for signals using transequatorial
propagation?
A. About 1,000 miles
B. About 2,500 miles
C. About 5,000 miles
D. About 7,500 miles
*
148C-3.3 C 3-12 Afternoon
What is the best time of day for transequatorial propagation?
A. Morning
B. Noon
C. Afternoon or early evening
D. Transequatorial propagation only works at night
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149C-4.1 C 3-13 Long-path
If a beam antenna must be pointed in a direction 180 degrees
away from a station to receive the strongest signals, what type
of propagation is probably occurring?
A. Transequatorial propagation
B. Sporadic-E propagation
C. Long-path propagation
D. Auroral propagation
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150C-5.1 D 3-14 Gray-line
What is the name for a type of propagation in which radio
signals travel along the terminator, which separates daylight
from darkness?
A. Transequatorial propagation
B. Sporadic-E propagation
C. Long-path propagation
D. Gray-line propagation
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151D-1A1 C 4-1  An oscilloscope is used to display electrical|signals in the time domain
How does a spectrum analyzer differ from a conventional
time-domain oscilloscope?
A. An oscilloscope is used to display electrical signals
   while the spectrum analyzer is used to measure ionospheric
   reflection
B. An oscilloscope is used to display electrical signals
   in the frequency domain while the spectrum analyzer is
   used to display electrical signals in the time domain
C. An oscilloscope is used to display electrical signals
   in the time domain while the spectrum analyzer is used
   to display electrical signals in the frequency domain
D. An oscilloscope is used to displaying audio frequencies
   and the spectrum analyzer is used for displaying radio
   frequencies
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152D-1A2 D 4-1  Frequency
What does the horizontal axis of a spectrum analyzer display?
A. Amplitude
B. Voltage
C. Resonance
D. Frequency
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153D-1A3 A 4-2  Amplitude
What does the vertical axis of a spectrum analyzer display?
A. Amplitude
B. Duration
C. Frequency
D. Time
*
154D-1B1 A 4-3  Spectrum analyzer
What test instrument can be used to display spurious signals in
the output of a radio transmitter?
A. A spectrum analyzer
B. A wattmeter
C. A logic analyzer
D. A time-domain reflectometer
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155D-1B2 B 4-4  Spectrum analyzer
What test instrument is used to display intermodulation
distortion products from a SSB transmitter?
A. A wattmeter
B. A spectrum analyzer
C. A logic analyzer
D. A time-domain reflectometer
*
156D-2A1 D 4-6  Simplified readout
What advantage does a logic probe have over a voltmeter for
monitoring logic states in a circuit?
A. A logic probe has fewer leads to connect to a circuit
   than a voltmeter
B. A logic probe can be used to test analog and digital
   circuits
C. A logic probe can be powered by commercial ac lines
D. A logic probe is smaller and shows a simplified readout
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157D-2A2 C 4-6  Logic probe
What piece of test equipment can be used to directly indicate
high and low logic states?
A. A galvanometer
B. An electroscope
C. A logic probe
D. A Wheatstone bridge
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158D-2A3 D 4-6  Logic states
What is a logic probe used to indicate?
A. A short-circuit fault in a digital-logic circuit
B. An open-circuit failure in a digital-logic circuit
C. A high-impedance ground loop
D. High and low logic states in a digital-logic circuit
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159D-2B1 A 4-6  Logic probe
What piece of test equipment besides an oscilloscope can be
used to indicate pulse conditions in a digital-logic circuit?
A. A logic probe
B. A galvanometer
C. An electroscope
D. A Wheatstone bridge
*
160D-3A1 A 4-6  Ignition noise
What is one of the most significant problems you might encounter
when you try to receive signals with a mobile station?
A. Ignition noise
B. Doppler shift
C. Radar interference
D. Mechanical vibrations
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161D-3A2 A 4-6  Shielding and filtering
What is the proper procedure for suppressing electrical noise in
a mobile station?
A. Apply shielding and filtering where necessary
B. Insulate all plane sheet metal surfaces from each other
C. Apply antistatic spray liberally to all non-metallic surfaces
D. Install filter capacitors in series with all dc wiring
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162D-3A3 C 4-6  Ignition leads
How can ferrite beads be used to suppress ignition noise?
A. Install them in the resistive high voltage cable every 2
   years
B. Install them between the starter solenoid and the starter
   motor
C. Install them in the primary and secondary ignition leads
D. Install them in the antenna lead to the radio
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163D-3A4 D 4-7  Lower frequencies don't radiate|as well as higher frequencies
How can ensuring good electrical contact between connecting
metal surfaces in a vehicle reduce spark plug noise?
A. It reduces the spark gap distance, causing a lower
   frequency spark
B. It helps radiate the spark plug noise away from the
   vehicle
C. It reduces static buildup on the vehicle
D. It encourages lower frequency electrical resonances
   in the vehicle
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164D-3B1 B 4-7  Why waste wire?
How can alternator whine be minimized?
A. By connecting the the radio's power leads to the battery by
   the longest possible path
B. By connecting the the radio's power leads to the battery
   by the shortest possible path
C. By installing a high pass filter in series with the radio's
   dc power lead to the vehicle's electrical system
D. By installing filter capacitors in series with the dc power
   lead
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165D-3B2 D 4-7  Connect the radio's power leads directly|to the battery and install capacitors in|the alternator leads
How can conducted and radiated noise caused by an automobile
alternator be suppressed?
A. By installing filter capacitors in series with the dc power
   lead and by installing a blocking capacitor in the field lead
B. By connecting the radio's power leads to the battery by the
   longest possible path and by installing a blocking capacitor
   in series with the positive lead
C. By installing a high pass filter in series with the radio's
   power lead to the vehicle's electrical system and by installing
   a low pass filter in parallel with the field lead
D. By connecting the radio's power lead directly to the battery
   and by installing coaxial capacitors in the alternator leads
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166D-3C1 B 4-7  Makes a lot of audible noise too
What is a major cause of atmospheric static?
A. Sunspots
B. Thunderstorms
C. Airplanes
D. Meteor showers
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167D-3D1 C 4-8  Keep it simple.  Buy a battery operated|radio.  Good to have during emergencies
How can you determine if a line-noise interference problem is
being generated within your home?
A. Check the power-line voltage with a time-domain reflectometer
B. Observe the ac waveform on an oscilloscope
C. Turn off the main circuit breaker and listen on a battery-
   operated radio
D. Observe the power-line voltage on a spectrum analyzer
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168D-4.1 A 4-10 Bidirectional
What is the main drawback of a wire-loop antenna for
direction finding?
A. It has a bidirectional pattern broadside to the loop
B. It is non-rotatable
C. It receives equally well in all directions
D. It is practical for use only on VHF bands
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169D-4.2 B 4-10 Good|Front-to-back|Front-to-side
What directional pattern is desirable for a direction-finding
antenna?
A. A non-cardioid pattern
B. Good front-to-back and front-to-side ratios
C. Good top-to-bottom and and front-to-side ratios
D. Shallow nulls
*
170D-4.3 C 4-14 Several receiving locations
What is the triangulation method of direction finding?
A. Using the geometric angle of ground waves and sky waves
   emanating from the same source to locate the signal source
B. A fixed receiving station uses three beam headings to plot
   the signal source on a map
C. Beam headings from several receiving locations are used
   to plot the signal source on a map
D. The use of three vertical antennas to indicate the location
   of the signal source
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171D-4.4 D 4-10 Prevents overload
Why is an RF attenuator desirable in a receiver used for
direction finding?
A. It narrows the bandwidth of the received signal
B. It eliminates the effects of isotropic radiation
C. It reduces loss of received signals caused by antenna
   pattern nulls
D. It prevents receiver overload from extremely strong
   signals
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172D-4.5 A 4-12 A vertical antenna added to a loop antenna
What is a sense antenna?
A. A vertical antenna added to a loop antenna to produce a
   cardioid reception pattern
B. A horizontal antenna added to a loop antenna to produce
   a cardioid reception pattern
C. A vertical antenna added to a Adcock antenna to produce
   an omnidirectional reception pattern
D. A horizontal antenna added to a Adcock antenna to produce
   a cardioid reception pattern
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173D-4.6 D 4-13 Adcock antenna
What type of antenna is most useful for sky-wave reception
in radio direction finding?
A. A log-periodic dipole array
B. An isotropic antenna
C. A circularly polarized antenna
D. An Adcock antenna
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174D-4.7 C 4-10 Loop used in radio direction finding
What is a loop antenna?
A. A circularly polarized antenna
B. A coil of wire used as an antenna in FM broadcast receivers
C. A wire loop used in radio direction finding
D. An antenna coupled to the feed line through an inductive
   loop of wire
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175D-4.8 D 4-11 Key word increase|Larger number of turns|Larger loop area
How can the output voltage of loop antenna be increased?
A. By reducing the permeability of the loop shield
B. By increasing the number of wire turns in the loop while
   reducing the area of the loop structure
C. By reducing either the number of wire turns in the loop,
   or the area of the loop structure
D. By increasing either the number of wire turns in the loop,
   or the area of the loop structure
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176D-4.9 B 4-12 Nulls are usually sharper than peaks
Why is an antenna system with a cardioid pattern desirable
for a direction-finding system?
A. The broad side responses of the cardioid pattern can be
   aimed at the desired station
B. The deep null of the cardioid pattern can pinpoint the
   direction of the desired station
C. The sharp peak response of the cardioid pattern can
   pinpoint the direction of the desired station
D. The high radiation angle of the cardioid pattern is
   useful for short-distance direction finding
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177D-4.10C 4-15 Varied terrain
What type of terrain can cause errors in direction finding?
A. Homogeneous terrain
B. Smooth grassy terrain
C. Varied terrain
D. Terrain with no buildings of mountains
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178E-1.1 B 5-3  Increased conductivity with illumination
What is the photoconductive effect?
A. The conversion of photon energy to electromotive energy
B. The increased conductivity of an illuminated semiconductor
   junction
C. The conversion of electromotive energy to photon energy
D. The decreased conductivity of an illuminated semiconductor
   junction
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179E-1.2 A 5-3  Conductivity increases |when light shines on it
What happens to photoconductive material when light shines
on it?
A. The conductivity of the material increases
B. The conductivity of the material decreases
C. The conductivity of the material stays the same
D. The conductivity of the material becomes temperature
   dependent
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180E-1.3 D 5-3  Resistance is the reciprocal of conductance|Resistance decreases when light shines on a|photoconductive material
What happens to the resistance of a photoconductive material
when light shines on it?
A. It increases
B. It becomes temperature dependent
C. It stays the same
D. It decreases
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181E-1.4 C 5-3  Conductivity increases |when light shines on it
What happens to the conductivity of a semiconductor junction
when it is illuminated?
A. It stays the same
B. It becomes temperature dependent
C. It increases
D. It decreases
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182E-1.5 D 5-4  LED and a phototransistor
What is an optocoupler?
A. A resistor and a capacitor
B. A frequency modulated helium-neon laser
C. An amplitude modulated helium-neon laser
D. An LED and a phototransistor
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183E-1.6 A 5-4  LED and a phototransistor
What is an optoisolator?
A. An LED and a phototransistor
B. A P-N junction that develops an excess positive charge
   when exposed to light
C. An LED and a capacitor
D. An LED and a solar cell
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184E-1.7 B 5-5  Light transmission controlled|by a rotating wheel
What is an optical shaft encoder?
A. An array of optocouplers chopped by a stationary wheel
B. An array of optocouplers whose light transmission path
   is controlled by a rotating wheel
C. An array of optocouplers whose propagation velocity is
   controlled by a stationary wheel
D. An array of optocouplers whose propagation velocity is
   controlled by a rotating wheel
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185E-1.8 D 5-3  The photoconductive effect is a change in   |the conductivity of a solid when illuminated|Resistance is the reciprocal of conductance
What does the photoconductive effect in crystalline solids
produce a noticeable change in?
A. The capacitance of the solid
B. The inductance of the solid
C. The specific gravity of the solid
D. The resistance of the solid
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186E-2A1 D 5-6  When a capacitor is charged,  the|voltage across the terminals rise|One τ = 63.2% of the supply volt.
What is the meaning of the term time constant of an RC circuit?
A. The time required to charge the capacitor in the circuit to
   36.8% of the supply voltage
B. The time required to charge the capacitor in the circuit to
   36.8% of the supply current
C. The time required to charge the capacitor in the circuit to
   63.2% of the supply current
D. The time required to charge the capacitor in the circuit to
   63.2% of the supply voltage
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187E-2A2 C 5-11 63.2% of the maximum current
What is the meaning of the term time constant of an RL circuit?
A. The time required for the current in the circuit to build
   up to 36.8% of the maximum value
B. The time required for the voltage in the circuit to build
   up to 63.2% of the maximum value
C. The time required for the current in the circuit to build
   up to 63.2% of the maximum value
D. The time required for the voltage in the circuit to build
   up to 36.8% of the maximum value
*
188E-2A3 B 5-8  Time constant
What is the term for the time required for the capacitor in
an RC circuit to be charged to 63.2% of the maximum value?
A. An exponential rate of one
B. One time constant
C. One exponential period
D. A time factor of one
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189E-2A4 A 5-11 Time constant
What is the term for the time required for the current in an
RL circuit to build up to 63.2% of the maximum value?
A. One time constant
B. An exponential period of one
C. A time factor of one
D. One exponential rate
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190E-2A5 D 5-8  Time constant
What is the term for the time it takes for a charged capacitor
in an RC circuit to discharge to 36.8% of its initial value of
stored charge?
A. One discharge period
B. An exponential discharge rate of one
C. A discharge factor of one
D. One time constant
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191E-2A6 D 5-11 ElectroMotive Force is  |another term for Voltage
What is meant by back EMF?
A. A current equal to the applied EMF
B. An opposing EMF equal to R times C (RC) percent of the
   applied EMF
C. A current that opposes the applied EMF
D. A voltage that opposes the applied EMF
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192E-2B1 C 5-8  For a capacitor being charged|100*(1-e(-1))% = 63.2%, One Time Constant |100*(1-e(-2))% = 86.5%, Two Time Constants
After two time constants, the capacitor in an RC circuit is
charged to what percentage of the supply voltage?
A. 36.8%
B. 63.2%
C. 86.5%
D. 95%
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193E-2B2 D 5-8  For a capacitor being discharged|100*(e(-1))% = 36.8%, One Time Constant |100*(e(-2))% = 13.5%, Two Time Constants
After two time constants, the capacitor in an RC circuit is
discharged to what percentage of the starting voltage?
A. 86.5%
B. 63.2%
C. 36.8%
D. 13.5%
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194E-2B3 C 5-7  τ = RC,  τ = 470E3*100E-6,  τ = 47
What is the time constant of a circuit having a 100-microfarad
capacitor in series with a 470-kilohm resistor?
A. 4700 seconds
B. 470 seconds
C. 47 seconds
D. 0.47 seconds
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195E-2B4 A 5-7  τ = RC, τ = 1E6*220E-6, τ = 220
What is the time constant of a circuit having a 220-microfarad
capacitor in parallel with a 1-megohm resistor?
A. 220 seconds
B. 22 seconds
C. 2.2 seconds
D. 0.22 seconds
*