Ham Radio 2000/Ham Radio 2000.iso/ham2000/exams/adv21/adv3.dat

Text File | 1993-03-09 | 18KB | 488 lines

114D-2.7   B 4-4   Less accurate
What happens in a dip-meter when it is too tightly coupled
with the tuned circuit being checked?
A. Harmonics are generated
B. A less accurate reading results
C. Cross modulation occurs
D. Intermodulation distortion occurs
*
115D-3.1   A 4-8   Oscillator  stability and|amplifier bandwidth
What factors limit the accuracy, frequency response, and stability
of an oscilloscope?
A. Sweep oscillator quality and deflection amplifier bandwidth
B. Tube face voltage increments and deflection amplifier voltage
C. Sweep oscillator quality and tube face voltage increments
D. Deflection amplifier output impedance and tube face frequency
   increments
*
116D-3.2   D 4-6   Mechanical tolerance & calibration
What factors limit the accuracy, frequency response, and stability
of a D'Arsonval movement type meter?
A. Calibration, coil impedance and meter size
B. Calibration, series resistance and electromagnet current
C. Coil impedance, electromagnet voltage and movement mass
D. Calibration, mechanical tolerance and coil impedance
*
117D-3.3   B 4-3   Time base most important for accuracy|and the speed of the logic determines|the frequency response
What factors limit the accuracy, frequency response, and stability
of a frequency counter?
A. Number of digits in the readout, speed of the logic and time
   base stability
B. Time base accuracy, speed of the logic and time base stability
C. Time base accuracy, temperature coefficient of the logic and
   time base stability
D. Number of digits in the readout, external frequency reference
   and temperature coefficient of the logic
*
118D-3.4   D 4-8   Better vertical amplifier
How can the frequency response of an oscilloscope be improved?
A. By using a triggered sweep and a crystal oscillator as the
   time base
B. By using a crystal oscillator as the time base and increasing
   the vertical sweep rate
C. By increasing the vertical sweep rate and the horizontal
   amplifier frequency response
D. By increasing the horizontal sweep rate and the vertical
   amplifier frequency response
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119D-3.5   C 4-3   Time base most important
How can the accuracy of a frequency counter be improved?
A. By using slower digital logic
B. By improving the accuracy of the frequency response
C. By increasing the accuracy of the time base
D. By using faster digital logic
*
120D-4.1   D 4-9   Intermod.
What is the condition called which occurs when the signals of two
transmitters in close proximity mix together in one or both of their
final amplifiers, and unwanted signals at the sum and difference
frequencies of the original transmissions are generated?
A. Amplifier desensitization
B. Neutralization
C. Adjacent channel interference
D. Intermodulation interference
*
121D-4.2   B 4-9   Mixing
How does intermodulation interference between two transmitters
usually occur?
A. When the signals from the transmitters are reflected out of
   phase from airplanes passing overhead
B. When they are in close proximity and the signals mix in one or
   both of their final amplifiers
C. When they are in close proximity and the signals cause
   feedback in one or both of their final amplifiers
D. When the signals from the transmitters are reflected in phase
   from airplanes passing overhead
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122D-4.3   B 4-9   Install an isolator
How can intermodulation interference between two transmitters
in close proximity often be reduced or eliminated?
A. By using a Class C final amplifier with high driving power
B. By installing a terminated circulator or ferrite isolator
   in the feed line to the transmitter and duplexer
C. By installing a band-pass filter in the antenna feed line
D. By installing a low-pass filter in the antenna feed line
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123D-4.4   D 4-9   Distortion will occur
What can occur when a non-linear amplifier is used with a
single-sideband phone transmitter?
A. Reduced amplifier efficiency
B. Increased intelligibility
C. Sideband inversion
D. Distortion
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124D-4.5   B 4-9   Push-pull
How can even-order harmonics be reduced or prevented in
transmitter amplifier design?
A. By using a push-push amplifier
B. By using a push-pull amplifier
C. By operating class C
D. By operating class AB
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125D-5.1   C 4-11  Loss of sensitivity by overload
What is receiver desensitizing?
A. A burst of noise when the squelch is set too low
B. A burst of noise when the squelch is set too high
C. A reduction in receiver sensitivity because of a
   strong signal on a nearby frequency
D. A reduction in receiver sensitivity when the AF
   gain control is turned down
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126D-5.2   A 4-11  Desensitizing
What is the term used to refer to the reduction of receiver
gain caused by the signals of a nearby station transmitting
in the same frequency band?
A. Desensitizing
B. Quieting
C. Cross modulation interference
D. Squelch gain rollback
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127D-5.3   C 4-11  Desensitizing
What is the term used to refer to a reduction in receiver
sensitivity caused by unwanted high-level adjacent channel
signals?
A. Intermodulation distortion
B. Quieting
C. Desensitizing
D. Overloading
*
128D-5.4   C 4-11  Loss of sensitivity by overload
What causes receiver desensitizing?
A. Audio gain adjusted too low
B. Squelch gain adjusted too high
C. The presence of a strong signal on a nearby
   frequency
D. Squelch gain adjusted too low
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129D-5.5   A 4-11  Shielding
How can receiver desensitizing be reduced?
A. Ensure good RF shielding between the transmitter
   and receiver
B. Increase the transmitter audio gain
C. Decrease the receiver squelch gain
D. Increase the receiver bandwidth
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130D-6.1   D 4-11  Signals from a strong station|are superimposed
What is cross-modulation interference?
A. Interference between two transmitters of different
   modulation type
B. Interference caused by audio rectification in the
   receiver preamp
C. Harmonic distortion of the transmitted signal
D. Modulation from an unwanted signal is heard in
   addition to the desired signal
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131D-6.2   B 4-12  Cross-modulation
What is the term used to refer to the condition where the
signals from a very strong station are superimposed on other
signals being received?
A. Intermodulation distortion
B. Cross-modulation interference
C. Receiver quieting
D. Capture effect
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132D-6.3   A 4-12  Filtering
How can cross-modulation in a receiver be reduced?
A. By installing a filter at the receiver
B. By using a better antenna
C. By increasing the receiver's RF gain while decreasing
   the AF gain
D. By adjusting the pass-band tuning
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133D-6.4   C 4-12  Signals from a strong station|are superimposed
What is the result of cross-modulation?
A. A decrease in modulation level of transmitted signals
B. Receiver quieting
C. The modulation of an unwanted signal is heard on the
   desired signal
D. Inverted sidebands in the final stage of the amplifier
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134D-7.1   C 4-12  Strong signal depresses weak signals
What is the capture effect?
A. All signals on a frequency are demodulated by an FM receiver
B. All signals on a frequency are demodulated by an AM receiver
C. The loudest signal received is the only demodulated signal
D. The weakest signal received is the only demodulated signal
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135D-7.2   C 4-12  Capture effect
What is the term used to refer to the reception blockage
of one FM-phone signal by another FM-phone signal?
A. Desensitization
B. Cross-modulation interference
C. Capture effect
D. Frequency discrimination
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136D-7.3   A 4-12  FM
With which emission type is the capture-effect most
pronounced?
A. FM
B. SSB
C. AM
D. CW
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137E-1.1   A 5-0   Current out of phase with voltage
What is reactive power?
A. Wattless, non-productive power
B. Power consumed in wire resistance in an inductor
C. Power lost because of capacitor leakage
D. Power consumed in circuit Q
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138E-1.2   D 5-0   Reactive
What is the term for an out-of-phase, non-productive
power associated with inductors and capacitors?
A. Effective power
B. True power
C. Peak envelope power
D. Reactive power
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139E-1.3   A 5-2   Potential
What is the term for energy that is stored in an
electromagnetic or electrostatic field?
A. Potential energy
B. Amperes-joules
C. Joules-coulombs
D. Kinetic energy
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140E-1.4   B 5-14  Resonance
What is responsible for the phenomenon when voltages
across reactances in series can often be larger than
the voltages applied to them?
A. Capacitance
B. Resonance
C. Conductance
D. Resistance
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141E-2.1   C 5-13  Xl = Xc
What is resonance in an electrical circuit?
A. The highest frequency that will pass current
B. The lowest frequency that will pass current
C. The frequency at which capacitive reactance equals
   inductive reactance
D. The frequency at which power factor is at a minimum
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142E-2.2   B 5-13  Xl = Xc
Under what conditions does resonance occur in an electrical
circuit?
A. When the power factor is at a minimum
B. When inductive and capacitive reactances are equal
C. When the square root of the sum of the capacitive and
   inductive reactances is equal to the resonant frequency
D. When the square root of the product of the capacitive and
   inductive reactances is equal to the resonant frequency
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143E-2.3   D 5-13  Resonance
What is the term for the phenomena which occurs in an
electrical circuit when the inductive reactance equals
the capacitive reactance?
A. Reactive quiescence
B. High Q
C. Reactive equilibrium
D. Resonance
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144E-2.4   B 5-15  For a series circuit Z = R +jXl -jXc|and at resonance Xl = Xc,  therefore|Z = R, the circuit resistance
What is the approximate magnitude of the impedance of a
series R-L-C circuit at resonance?
A. High, as compared to the circuit resistance
B. Approximately equal to the circuit resistance
C. Approximately equal to XL
D. Approximately equal to XC
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145E-2.5   A 5-15  ≈ the circuit resistance
What is the approximate magnitude of the impedance of a
parallel R-L-C circuit at resonance?
A. Approximately equal to the circuit resistance
B. Approximately equal to XL
C. Low, as compared to the circuit resistance
D. Approximately equal to XC
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146E-2.6   B 5-15  Maximum
What is the characteristic of the current flow in a series
R-L-C circuit at resonance?
A. It is at a minimum
B. It is at a maximum
C. It is DC
D. It is zero
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147E-2.7   B 5-15  Circulating current is maximum
What is the characteristic of the current flow in a parallel
R-L-C circuit at resonance?
A. The current circulating in the parallel elements is at a
   minimum
B. The current circulating in the parallel elements is at a
   maximum
C. The current circulating in the parallel elements is DC
D. The current circulating in the parallel elements is zero
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148E-3.1   A 5-19  RF current flows on the surface
What is the skin effect?
A. The phenomenon where RF current flows in a thinner layer of
   the conductor, close to the surface, as frequency increases
B. The phenomenon where RF current flows in a thinner layer of
   the conductor, close to the surface, as frequency decreases
C. The phenomenon where thermal effects on the surface of the
   conductor increase the impedance
D. The phenomenon where thermal effects on the surface of the
   conductor decrease the impedance
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149E-3.2   C 5-19  Skin effect
What is the term for the phenomenon where most of an RF
current flows along the surface of the conductor?
A. Layer effect
B. Seeburg Effect
C. Skin effect
D. Resonance
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150E-3.3   A 5-19  RF current flows on the surface
Where does practically all of the RF current flow in a
conductor?
A. Along the surface
B. In the center of the conductor
C. In the magnetic field around the conductor
D. In the electromagnetic field in the conductor center
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151E-3.4   A 5-19  Called skin effect
Why does practically all of an RF current flow within a few
thousandths-of-an-inch of the conductor's surface?
A. Because of skin effect
B. Because the RF resistance of the conductor is much less
   than the DC resistance
C. Because of heating of the metal at the conductor's interior
D. Because of the AC-resistance of the conductor's self
   inductance
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152E-3.5   C 5-19  RF current flows on the surface
Why is the resistance of a conductor different for RF
current than for DC?
A. Because the insulation conducts current at radio
   frequencies
B. Because of the Heisenburg Effect
C. Because of skin effect
D. Because conductors are non-linear devices
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153E-4.1   B 5-4   Field produced by a magnet|or by an electric current
What is a magnetic field?
A. Current flow through space around a permanent magnet
B. A force set up when current flows through a conductor
C. The force between the plates of a charged capacitor
D. The force that drives current through a resistor
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154E-4.2   D 5-4   Found by the left hand rule
In what direction is the magnetic field about a conductor
when current is flowing?
A. In the same direction as the current
B. In a direction opposite to the current flow
C. In all directions; omnidirectional
D. In a direction determined by the left hand rule
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155E-4.3   C 5-2   Capacitor
What device is used to store electrical energy in an
electrostatic field?
A. A battery
B. A transformer
C. A capacitor
D. An inductor
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156E-4.4   B 5-3   Joules
What is the term used to express the amount of electrical
energy stored in an electrostatic field?
A. Coulombs
B. Joules
C. Watts
D. Volts
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157E-4.5   B 5-3   Area, distance apart, and|dielectric constant
What factors determine the capacitance of a capacitor?
A. Area of the plates, voltage on the plates and distance
   between the plates
B. Area of the plates, distance between the plates and the
   dielectric constant of the material between the plates
C. Area of the plates, voltage on the plates and the dielectric
   constant of the material between the plates
D. Area of the plates, amount of charge on the plates and the
   dielectric constant of the material between the plates
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158E-4.6   A 5-3   Unity
What is the dielectric constant for air?
A. Approximately 1
B. Approximately 2
C. Approximately 4
D. Approximately 0
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159E-4.7   D 5-4   Amount of current
What determines the strength of the magnetic field
around a conductor?
A. The resistance divided by the current
B. The ratio of the current to the resistance
C. The diameter of the conductor
D. The amount of current
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160E-5.1   C 5-14  F = _____1____         L*C = 2.00E-15|    2*π*√(L*C)       √(L*C) = 4.47E-8|F = 1/(6.28*4.47E-8),   F = 1/2.81E-7
What is the resonant frequency of the circuit in Figure 4AE-5-1
when L is 50 microhenrys and C is 40 picofarads?
A. 79.6 MHz
B. 1.78 MHz
C. 3.56 MHz
D. 7.96 MHz
*
161E-5.2   B 5-14  F = _____1____         L*C = 8.00E-15|    2*π*√(L*C)       √(L*C) = 8.94E-8|F = 1/(6.28*8.94E-8),   F = 1/5.62E-7
What is the resonant frequency of the circuit in Figure 4AE-5-1
when L is 40 microhenrys and C is 200 picofarads?
A. 1.99 kHz
B. 1.78 MHz
C. 1.99 MHz
D. 1.78 kHz
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162E-5.3   C 5-14  F = 1/(6.28*√(50E-6*10E-12))|1. Multiply L*C       2. Take √  |3. Multiply by 6.28   3. Take 1/X
What is the resonant frequency of the circuit in Figure 4AE-5-1
when L is 50 microhenrys and C is 10 picofarads?
A. 3.18 MHz
B. 3.18 kHz
C. 7.12 MHz
D. 7.12 kHz
*
163E-5.4   A 5-14  F = 1/6.28*√(25E-6*10E-12)|1. Multiply L*C       2. Take √  |3. Multiply by 6.28   3. Take 1/X
What is the resonant frequency of the circuit in Figure 4AE-5-1
when L is 25 microhenrys and C is 10 picofarads?
A. 10.1 MHz
B. 63.7 MHz
C. 10.1 kHz
D. 63.7 kHz
*
164E-5.5   B 5-14  F = 1/6.28*√(3E-6*40E-12)|1. Multiply L*C       2. Take √  |3. Multiply by 6.28   3. Take 1/X
What is the resonant frequency of the circuit in Figure 4AE-5-1
when L is 3 microhenrys and C is 40 picofarads?
A. 13.1 MHz
B. 14.5 MHz
C. 14.5 kHz
D. 13.1 kHz
*
165E-5.6   D 5-14  F = 1/6.28*√(4E-6*20E-12)|1. Multiply L*C       2. Take √  |3. Multiply by 6.28   3. Take 1/X
What is the resonant frequency of the circuit in Figure 4AE-5-1
when L is 4 microhenrys and C is 20 picofarads?
A. 19.9 kHz
B. 17.8 kHz
C. 19.9 MHz
D. 17.8 MHz
*
166E-5.7   C 5-14  F = _____1____         L*C = 5.60E-17|    2*π*√(L*C)       √(L*C) = 7.48E-9|F = 1/(6.28*7.48E-9),   F = 1/4.70E-8
What is the resonant frequency of the circuit in Figure 4AE-5-1
when L is 8 microhenrys and C is 7 picofarads?
A. 2.84 MHz
B. 28.4 MHz
C. 21.3 MHz
D. 2.13 MHz
*
167E-5.8   A 5-14  F = 1/6.28*√(3E-6*15E-12)|1. Multiply L*C       2. Take √  |3. Multiply by 6.28   3. Take 1/X
What is the resonant frequency of the circuit in Figure 4AE-5-1
when L is 3 microhenrys and C is 15 picofarads?
A. 23.7 MHz
B. 23.7 kHz
C. 35.4 kHz
D. 35.4 MHz
*
168E-5.9   B 5-14  F = 1/6.28*√(4E-6*8E-12) |1. Multiply L*C       2. Take √  |3. Multiply by 6.28   3. Take 1/X
What is the resonant frequency of the circuit in Figure 4AE-5-1
when L is 4 microhenrys and C is 8 picofarads?
A. 28.1 kHz
B. 28.1 MHz
C. 49.7 MHz
D. 49.7 kHz
*
169E-5.10  C 5-14  F = 1/6.28*√(1E-6*9E-12)|1. Multiply L*C       2. Take √  |3. Multiply by 6.28   3. Take 1/X
What is the resonant frequency of the circuit in Figure 4AE-5-1
when L is 1 microhenry and C is 9 picofarads?
A. 17.7 MHz
B. 17.7 kHz
C. 53.1 MHz
D. 53.1 kHz
*
170E-5.11  A 5-14  F = _____1____         L*C = 1.00E-17|    2*π*√(L*C)       √(L*C) = 3.16E-9|F = 1/(6.28*3.16E-9),   F = 1/1.99E-8
What is the resonant frequency of the circuit in Figure 4AE-5-2
when L is 1 microhenry and C is 10 picofarads?
A. 50.3 MHz
B. 15.9 MHz
C. 15.9 kHz
D. 50.3 kHz
*