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US Amateur Radio - Amateur Extra (Element 4, 2020-2024) Practice Test

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1. - E0A02

When evaluating RF exposure levels from your station at a neighbor's home, what must you do?

SelectAnswer
AEnsure signals from your station are less than the controlled Maximum Permitted Exposure (MPE) limits
BEnsure signals from your station are less than the uncontrolled Maximum Permitted Emission (MPE) limits
CEnsure signals from your station are less than the controlled Maximum Permitted Emission (MPE) limits
DEnsure signals from your station are less than the uncontrolled Maximum Permitted Exposure (MPE) limits

2. - E1A03

What is the maximum legal carrier frequency on the 20 meter band for transmitting USB AFSK digital signals having a 1 kHz bandwidth?

SelectAnswer
A14.100 MHz
B14.149 MHz
C14.349 MHz
D14.070 MHz

3. - E1B07

To what type of regulations does PRB-1 apply?

SelectAnswer
AState and local zoning
BFAA tower height limits
CHomeowners associations
DUse of wireless devices in vehicles

4. - E1C01

What is the maximum bandwidth for a data emission on 60 meters?

SelectAnswer
A170 Hz
B2.8 kHz
C60 Hz
D1.5 kHz

5. - E1D08

Which VHF amateur bands have frequencies authorized for space stations?

SelectAnswer
A2 meters
B6 meters and 2 meters
C2 meters and 1.25 meters
D6 meters, 2 meters, and 1.25 meters

6. - E1E10

What must the administering VEs do after the administration of a successful examination for an amateur operator license?

SelectAnswer
AThey must collect and send the documents to the FCC according to instructions
BThey must submit the application document to the coordinating VEC according to the coordinating VEC instructions
CThey must collect and submit the documents to the coordinating VEC for grading
DThey must collect and send the documents to the NCVEC for grading

7. - E1F01

On what frequencies are spread spectrum transmissions permitted?

SelectAnswer
AOnly on amateur frequencies above 50 MHz
BOnly on amateur frequencies above 420 MHz
COnly on amateur frequencies above 222 MHz
DOnly on amateur frequencies above 144 MHz

8. - E2A10

What type of satellite appears to stay in one position in the sky?

SelectAnswer
AGeostationary
BLEO
CGeomagnetic
DHEO

9. - E2B10

What aspect of an analog slow-scan television signal encodes the brightness of the picture?

SelectAnswer
ATone amplitude
BTone frequency
CSync amplitude
DSync frequency

10. - E2C08

Which of the following contacts may be confirmed through the U.S. QSL bureau system?

SelectAnswer
ASpecial event contacts between stations in the U.S.
BRepeater contacts between U.S. club members
CContacts between a U.S. station and a non-U.S. station
DContacts using tactical call signs

11. - E2D08

What type of packet frame is used to transmit APRS beacon data?

SelectAnswer
AConnect
BDisconnect
CUnnumbered Information
DAcknowledgement

12. - E2E10

Which of these digital modes has the narrowest bandwidth?

SelectAnswer
A300-baud packet
B170 Hz shift, 45-baud RTTY
CMFSK16
DPSK31

13. - E3A13

Which of these emission modes is best for auroral propagation?

SelectAnswer
ACW
BRTTY
CSSB
DFM

14. - E3B11

At what time of day can sporadic E propagation occur?

SelectAnswer
AOnly in hours of darkness
BOnly around sunset
CAny time
DOnly around sunset and sunrise

15. - E3C09

How does the intensity of an X3 flare compare to that of an X2 flare?

SelectAnswer
AFour times as great
B50 percent greater
C10 percent greater
DTwice as great

16. - E4A01

Which of the following limits the highest frequency signal that can be accurately displayed on a digital oscilloscope?

SelectAnswer
ASampling rate of the analog-to-digital converter
BQ of the circuit
CAmount of memory
DAll these choices are correct

17. - E4B04

Which S parameter represents input port return loss or reflection coefficient (equivalent to VSWR)?

SelectAnswer
AS12
BS11
CS21
DS22

18. - E4C11

Why can an attenuator be used to reduce receiver overload on the lower frequency HF bands with little or no impact on signal-to-noise ratio?

SelectAnswer
AThe attenuator has a low-pass filter to increase the strength of lower frequency signals
BAtmospheric noise is generally greater than internally generated noise even after attenuation
CThe attenuator has a noise filter to suppress interference
DSignals are attenuated separately from the noise

19. - E4D10

What does a third-order intercept level of 40 dBm mean with respect to receiver performance?

SelectAnswer
AA pair of 40 dBm input signals will theoretically generate a third-order intermodulation product that has the same output amplitude as either of the input signals
BThe receiver can tolerate signals up to 40 dB above the noise floor without producing third-order intermodulation products
CSignals less than 40 dBm will not generate audible third-order intermodulation products
DA pair of 1 mW input signals will produce a third-order intermodulation product that is 40 dB stronger than the input signal

20. - E4E10

What might be the cause of a loud roaring or buzzing AC line interference that comes and goes at intervals?

SelectAnswer
AA malfunctioning illuminated advertising display
BAll these choices are correct
CArcing contacts in a thermostatically controlled device
DA defective doorbell or doorbell transformer inside a nearby residence

21. - E5A15

Which of the following increases Q for inductors and capacitors?

SelectAnswer
ALower losses
BHigher self-resonant frequency
CLower reactance
DLower self-resonant frequency

22. - E5B05

What happens to the magnitude of a pure reactance when it is converted to a susceptance?

SelectAnswer
AIt becomes the reciprocal
BIt is shifted by 90 degrees
CIt is unchanged
DThe sign is reversed

23. - E5C03

Which of the following represents an inductive reactance in polar coordinates?

SelectAnswer
AA positive phase angle
BA positive magnitude
CA negative phase angle
DA negative magnitude

24. - E5D06

In what direction is the magnetic field oriented about a conductor in relation to the direction of electron flow?

SelectAnswer
AIn a direction opposite to the current
BIn a circle around the conductor
CIn all directions; omni-directional
DIn the same direction as the current

25. - E6A12

Why do many MOSFET devices have internally connected Zener diodes on the gates?

SelectAnswer
ATo provide a voltage reference for the correct amount of reverse-bias gate voltage
BTo keep the gate voltage within specifications and prevent the device from overheating
CTo reduce the chance of static damage to the gate
DTo protect the substrate from excessive voltages

26. - E6B01

What is the most useful characteristic of a Zener diode?

SelectAnswer
AA constant voltage drop under conditions of varying current
BAn internal capacitance that varies with the applied voltage
CA constant current drop under conditions of varying voltage
DA negative resistance region

27. - E6C11

In Figure E6-3, what is the schematic symbol for the NOT operation (inverter)?

SelectAnswer
A5
B6
C2
D4

28. - E6D03

Which of the following is an aspect of the piezoelectric effect?

SelectAnswer
AMechanical deformation of material by the application of a voltage
BGeneration of electrical energy in the presence of light
CMechanical deformation of material by the application of a magnetic field
DIncreased conductivity in the presence of light

29. - E6E05

Which of the following noise figure values is typical of a low-noise UHF preamplifier?

SelectAnswer
A-10 dB
B44 dBm
C-20 dBm
D2 dB

30. - E6F08

Why are optoisolators often used in conjunction with solid-state circuits when switching 120 VAC?

SelectAnswer
AOptoisolators eliminate the effects of reflected light in the control circuit
BOptoisolators provide impedance matching between the control circuit and power circuit
COptoisolators provide a very high degree of electrical isolation between a control circuit and the circuit being switched
DOptoisolators provide a low impedance link between a control circuit and a power circuit

31. - E7A05

Which of the following is a circuit that continuously alternates between two states without an external clock?

SelectAnswer
AT flip-flop
BMonostable multivibrator
CAstable multivibrator
DJ-K flip-flop

32. - E7B08

How can an RF power amplifier be neutralized?

SelectAnswer
ABy feeding a 180-degree out-of-phase portion of the output back to the input
BBy feeding an in-phase component of the output back to the input
CBy increasing the driving power
DBy reducing the driving power

33. - E7C11

Which of the following describes a receiving filter's ability to reject signals occupying an adjacent channel?

SelectAnswer
ANoise factor
BPassband ripple
CShape factor
DPhase response

34. - E7D15

What is the purpose of a step-start circuit in a high-voltage power supply?

SelectAnswer
ATo allow for remote control of the power supply
BTo provide a dual-voltage output for reduced power applications
CTo allow the filter capacitors to charge gradually
DTo compensate for variations of the incoming line voltage

35. - E7E05

What circuit is added to an FM transmitter to boost the higher audio frequencies?

SelectAnswer
AA pre-emphasis network
BA heterodyne suppressor
CA heterodyne enhancer
DA de-emphasis network

36. - E7F08

What is the function of decimation?

SelectAnswer
ARemoving unnecessary significant digits
BReducing the effective sample rate by removing samples
CAttenuating the signal
DConverting data to binary code decimal form

37. - E7G07

What magnitude of voltage gain can be expected from the circuit in Figure E73 when R1 is 10 ohms and RF is 470 ohms?

SelectAnswer
A94
B24
C0.21
D47

38. - E7H01

What are three oscillator circuits used in amateur radio equipment?

SelectAnswer
APierce, Fenner and Beane
BColpitts, Hartley and Pierce
CTaft, Hartley and Pierce
DTaft, Pierce and negative feedback

39. - E8A04

What is "dither" with respect to analog-to-digital converters?

SelectAnswer
AAn error caused by irregular quantization step size
BA method of decimation by randomly skipping samples
CAn abnormal condition where the converter cannot settle on a value to represent the signal
DA small amount of noise added to the input signal to allow more precise representation of a signal over time

40. - E8B05

What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus-or-minus 5 kHz when the maximum modulation frequency is 3 kHz?

SelectAnswer
A0.167
B60
C1.67
D0.6

41. - E8C01

How is Forward Error Correction implemented?

SelectAnswer
ABy transmitting extra data that may be used to detect and correct transmission errors
BBy varying the frequency shift of the transmitted signal according to a predefined algorithm
CBy transmitting a special algorithm to the receiving station along with the data characters
DBy the receiving station repeating each block of three data characters

42. - E8D09

What is considered an acceptable maximum IMD level for an idling PSK signal?

SelectAnswer
A-20 dB
B+10 dB
C+15 dB
D-30 dB

43. - E9A10

Which of the following improves the efficiency of a ground-mounted quarter-wave vertical antenna?

SelectAnswer
AAll these choices are correct
BShortening the radiating element
CIsolating the coax shield from ground
DInstalling a radial system

44. - E9B04

What is the front-to-back ratio of the radiation pattern shown in Figure E92?

SelectAnswer
A28 dB
B3 dB
C38 dB
D15 dB

45. - E9C05

Which of the following is a type of OCFD antenna?

SelectAnswer
AA dipole fed approximately 1/3 the way from one end with a 4:1 balun to provide multiband operation
BA remotely tunable dipole antenna using orthogonally controlled frequency diversity
CA multiband dipole antenna using one-way circular polarization for frequency diversity
DA folded dipole center-fed with 300-ohm transmission line

46. - E9D11

Which of the following conductors would be best for minimizing losses in a station's RF ground system?

SelectAnswer
ASolid wire
BResistive wire, such as spark plug wire
CStranded wire
DWide flat copper strap

47. - E9E03

What is the name of the matching system that uses a section of transmission line connected in parallel with the feed line at or near the feed point?

SelectAnswer
AThe stub match
BThe gamma match
CThe omega match
DThe delta match

48. - E9F03

Why is the physical length of a coaxial cable transmission line shorter than its electrical length?

SelectAnswer
AElectrical signals move more slowly in a coaxial cable than in air
BThe characteristic impedance is higher in a parallel feed line
CSkin effect is less pronounced in the coaxial cable
DThe surge impedance is higher in a parallel feed line

49. - E9G06

On the Smith chart shown in Figure E9-3, what is the name for the large outer circle on which the reactance arcs terminate?

SelectAnswer
APrime axis
BImpedance axis
CReactance axis
DPolar axis

50. - E9H04

What is an advantage of placing a grounded electrostatic shield around a small loop direction-finding antenna?

SelectAnswer
AIt eliminates unbalanced capacitive coupling to the surroundings, improving the nulls
BIt eliminates tracking errors caused by strong out-of-band signals
CIt increases signal strength by providing a better match to the feed line
DIt adds capacitive loading, increasing the bandwidth of the antenna

Figure E6-3

Figure E9-3