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

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1. - E0A05

What is one of the potential hazards of operating in the amateur radio microwave bands?

Select	Answer
A	The extremely high frequency energy can damage the joints of antenna structures
B	Microwaves often travel long distances by ionospheric reflection
C	The high gain antennas commonly used can result in high exposure levels
D	Microwaves are ionizing radiation

2. - E1A01

Which of the following carrier frequencies is illegal for LSB AFSK emissions on the 17 meter band RTTY and data segment of 18.068 to 18.110 MHz?

Select	Answer
A	18.100 MHz
B	18.107 MHz
C	18.110 MHz
D	18.068 MHz

3. - E1B09

Which amateur stations may be operated under RACES rules?

Select	Answer
A	Only those club stations licensed to Amateur Extra Class operators
B	Any FCC-licensed amateur station participating in the Military Auxiliary Radio System (MARS)
C	Any FCC-licensed amateur station certified by the responsible civil defense organization for the area served
D	Any FCC-licensed amateur station except a Technician Class

4. - E1C08

What is the maximum permissible duration of a remotely controlled station's transmissions if its control link malfunctions?

Select	Answer
A	3 minutes
B	30 seconds
C	5 minutes
D	10 minutes

5. - E1D02

Which of the following may transmit special codes intended to obscure the meaning of messages?

Select	Answer
A	Auxiliary relay links carrying repeater audio
B	Binary control characters
C	Data containing personal information
D	Telecommand signals from a space telecommand station

6. - E1E03

What is a Volunteer Examiner Coordinator?

Select	Answer
A	An organization that has entered into an agreement with the FCC to coordinate, prepare, and administer amateur operator license examinations
B	The person who has entered into an agreement with the FCC to be the VE session manager
C	A person who has volunteered to administer amateur operator license examinations
D	A person who has volunteered to prepare amateur operator license examinations

7. - E1F03

Under what circumstances may a dealer sell an external RF power amplifier capable of operation below 144 MHz if it has not been granted FCC certification?

Select	Answer
A	It was imported from a manufacturer in another country and was certificated by that country's government
B	It was imported from a manufacturer in a country that does not require certification of RF power amplifiers
C	It was purchased in used condition from an amateur operator and is sold to another amateur operator for use at that operator's station
D	The equipment dealer assembled it from a kit

8. - E2A11

What type of antenna can be used to minimize the effects of spin modulation and Faraday rotation?

Select	Answer
A	An isotropic antenna
B	A linearly polarized antenna
C	A log-periodic dipole array
D	A circularly polarized antenna

9. - E2B09

What hardware, other than a receiver with SSB capability and a suitable computer, is needed to decode SSTV using Digital Radio Mondiale (DRM)?

Select	Answer
A	A special front end limiter
B	A special notch filter to remove synchronization pulses
C	A special IF converter
D	No other hardware is needed

10. - E2C10

Why might a DX station state that they are listening on another frequency?

Select	Answer
A	To improve operating efficiency by reducing interference
B	All these choices are correct
C	Because the DX station may be transmitting on a frequency that is prohibited to some responding stations
D	To separate the calling stations from the DX station

11. - E2D03

Which of the following digital modes is especially useful for EME communications?

Select	Answer
A	MSK144
B	PACTOR III
C	JT65
D	Olivia

12. - E2E09

Which of the following HF digital modes uses variable-length coding for bandwidth efficiency?

Select	Answer
A	MT63
B	PSK31
C	PACTOR
D	RTTY

13. - E3A13

Which of these emission modes is best for auroral propagation?

Select	Answer
A	CW
B	RTTY
C	FM
D	SSB

14. - E3B12

What is the primary characteristic of chordal hop propagation?

Select	Answer
A	Successive ionospheric refractions without an intermediate reflection from the ground
B	Signals reflected back toward the transmitting station
C	Propagation across the geomagnetic equator
D	Propagation away from the great circle bearing between stations

15. - E3C02

What is indicated by a rising A or K index?

Select	Answer
A	Decreasing disruption of the geomagnetic field
B	An increase in the critical frequency
C	Higher levels of solar UV radiation
D	Increasing disruption of the geomagnetic field

16. - E4A02

Which of the following parameters does a spectrum analyzer display on the vertical and horizontal axes?

Select	Answer
A	SWR and frequency
B	RF amplitude and time
C	SWR and time
D	RF amplitude and frequency

17. - E4B01

Which of the following factors most affects the accuracy of a frequency counter?

Select	Answer
A	Input attenuator accuracy
B	Decade divider accuracy
C	Time base accuracy
D	Temperature coefficient of the logic

18. - E4C08

An SDR receiver is overloaded when input signals exceed what level?

Select	Answer
A	One-half the maximum sampling buffer size
B	The reference voltage of the analog-to-digital converter
C	One-half the maximum sample rate
D	The maximum count value of the analog-to-digital converter

19. - E4D01

What is meant by the blocking dynamic range of a receiver?

Select	Answer
A	The difference in dB between the noise floor and the level of an incoming signal that will cause 1 dB of gain compression
B	The minimum difference in dB between the levels of two FM signals that will cause one signal to block the other
C	The minimum difference in dB between two signals which produce third-order intermodulation products greater than the noise floor
D	The difference in dB between the noise floor and the third-order intercept point

20. - E4E10

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

Select	Answer
A	Arcing contacts in a thermostatically controlled device
B	A malfunctioning illuminated advertising display
C	A defective doorbell or doorbell transformer inside a nearby residence
D	All these choices are correct

21. - E5A11

What is the half-power bandwidth of a resonant circuit that has a resonant frequency of 7.1 MHz and a Q of 150?

Select	Answer
A	157.8 Hz
B	47.3 kHz
C	23.67 kHz
D	315.6 Hz

22. - E5B12

What is admittance?

Select	Answer
A	The inverse of impedance
B	The inverse of Q factor
C	The turns ratio of a transformer
D	The term for the gain of a field effect transistor

23. - E5C03

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

Select	Answer
A	A negative magnitude
B	A positive phase angle
C	A negative phase angle
D	A positive magnitude

24. - E5D11

What is the power factor of an RL circuit having a 60-degree phase angle between the voltage and the current?

Select	Answer
A	0.866
B	1.73
C	1.414
D	0.5

25. - E6A03

Why does a PN-junction diode not conduct current when reverse biased?

Select	Answer
A	Only N-type semiconductor material can conduct current
B	Excess holes in P-type material combine with the electrons in N-type material, converting the entire diode into an insulator
C	Holes in P-type material and electrons in the N-type material are separated by the applied voltage, widening the depletion region
D	Only P-type semiconductor material can conduct current

26. - E6B08

Which of the following is a Schottky barrier diode?

Select	Answer
A	Electrolytic rectifier
B	Metal-semiconductor junction
C	Thermionic emission diode
D	PIN junction

27. - E6C07

What best describes a pull-up or pull-down resistor?

Select	Answer
A	A resistor connected to the positive or negative supply line used to establish a voltage when an input or output is an open circuit
B	A resistor connected to an op-amp output that prevents signals from exceeding the power supply voltage
C	A resistor in a keying circuit used to reduce key clicks
D	A resistor that ensures that an oscillator frequency does not drift

28. - E6D01

Why should core saturation of an impedance matching transformer be avoided?

Select	Answer
A	Magnetic flux would increase with frequency
B	Temporary changes of the core permeability could result
C	RF susceptance would increase
D	Harmonics and distortion could result

29. - E6E04

Which is the most common input and output impedance of circuits that use MMICs?

Select	Answer
A	300 ohms
B	450 ohms
C	50 ohms
D	10 ohms

30. - E6F09

What is the efficiency of a photovoltaic cell?

Select	Answer
A	Cost per kilowatt-hour generated
B	The relative fraction of light that is converted to current
C	The open-circuit voltage divided by the short-circuit current under full illumination
D	The output RF power divided by the input DC power

31. - E7A05

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

Select	Answer
A	J-K flip-flop
B	Monostable multivibrator
C	T flip-flop
D	Astable multivibrator

32. - E7B01

For what portion of the signal cycle does each active element in a push-pull Class AB amplifier conduct?

Select	Answer
A	Less than 180 degrees
B	Exactly 180 degrees
C	More than 180 degrees but less than 360 degrees
D	The entire cycle

33. - E7C11

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

Select	Answer
A	Passband ripple
B	Phase response
C	Shape factor
D	Noise factor

34. - E7D08

What type of circuit is shown in Figure E7-2?

Select	Answer
A	Grounded emitter amplifier
B	Switching voltage regulator
C	Linear voltage regulator
D	Monostable multivibrator

35. - E7E02

What is the function of a reactance modulator?

Select	Answer
A	To produce AM signals by using an electrically variable inductance or capacitance
B	To produce AM signals by using an electrically variable resistance
C	To produce PM signals by using an electrically variable resistance
D	To produce PM or FM signals by using an electrically variable inductance or capacitance

36. - E7F03

What type of digital signal processing filter is used to generate an SSB signal?

Select	Answer
A	An elliptical filter
B	A notch filter
C	A Hilbert-transform filter
D	An adaptive filter

37. - E7G04

What is meant by the "op-amp input offset voltage"?

Select	Answer
A	The differential input voltage needed to bring the open loop output voltage to zero
B	The potential between the amplifier input terminals of the op-amp in an open loop condition
C	The output voltage of the op-amp minus its input voltage
D	The difference between the output voltage of the op-amp and the input voltage required in the immediately following stage

38. - E7H09

What type of frequency synthesizer circuit uses a phase accumulator, lookup table, digital to analog converter, and a low-pass anti-alias filter?

Select	Answer
A	A hybrid synthesizer
B	A phase-locked loop synthesizer
C	A direct digital synthesizer
D	A diode-switching matrix synthesizer

39. - E8A08

Why would a direct or flash conversion analog-to-digital converter be useful for a software defined radio?

Select	Answer
A	Very high speed allows digitizing high frequencies
B	Immunity to out-of-sequence coding reduces spurious responses
C	All these choices are correct
D	Very low power consumption decreases frequency drift

40. - E8B01

What is the modulation index of an FM signal?

Select	Answer
A	The ratio of modulating signal amplitude to frequency deviation
B	The type of modulation used by the transmitter
C	The bandwidth of the transmitted signal divided by the modulating signal frequency
D	The ratio of frequency deviation to modulating signal frequency

41. - E8C09

Which digital code allows only one bit to change between sequential code values?

Select	Answer
A	Binary Coded Decimal Code
B	Excess 3 code
C	Extended Binary Coded Decimal Interchange Code
D	Gray code

42. - E8D11

What is one advantage of using ASCII code for data communications?

Select	Answer
A	It contains fewer information bits per character than any other code
B	It includes built-in error correction features
C	It uses one character as a shift code to send numeric and special characters
D	It is possible to transmit both upper and lower case text

43. - E9A01

What is an isotropic antenna?

Select	Answer
A	A horizontally polarized antenna used to compare Yagi antennas
B	A grounded antenna used to measure Earth conductivity
C	A spacecraft antenna used to direct signals toward Earth
D	A theoretical, omnidirectional antenna used as a reference for antenna gain

44. - E9B09

What type of computer program technique is commonly used for modeling antennas?

Select	Answer
A	Graphical analysis
B	Method of Moments
C	Calculus differentiation with respect to physical properties
D	Mutual impedance analysis

45. - E9C14

How does the performance of a horizontally polarized antenna mounted on the side of a hill compare with the same antenna mounted on flat ground?

Select	Answer
A	The horizontal beamwidth decreases in the downhill direction
B	The main lobe takeoff angle decreases in the downhill direction
C	The main lobe takeoff angle increases in the downhill direction
D	The horizontal beamwidth increases in the uphill direction

46. - E9D04

Why should an HF mobile antenna loading coil have a high ratio of reactance to resistance?

Select	Answer
A	To minimize losses
B	To swamp out harmonics
C	To lower the radiation angle
D	To minimize the Q

47. - E9E05

How must an antenna's driven element be tuned to use a hairpin matching system?

Select	Answer
A	The driven element reactance must be inductive
B	The driven element radiation resistance must be higher than the characteristic impedance of the transmission line
C	The driven element resonance must be lower than the operating frequency
D	The driven element reactance must be capacitive

48. - E9F03

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

Select	Answer
A	Electrical signals move more slowly in a coaxial cable than in air
B	The surge impedance is higher in a parallel feed line
C	The characteristic impedance is higher in a parallel feed line
D	Skin effect is less pronounced in the coaxial cable

49. - E9G02

What type of coordinate system is used in a Smith chart?

Select	Answer
A	Voltage lines and current chords
B	Resistance lines and reactance chords
C	Resistance circles and reactance arcs
D	Voltage circles and current arcs

50. - E9H03

What is Receiving Directivity Factor (RDF)?

Select	Answer
A	Relative directivity compared to a dipole
B	Relative directivity compared to isotropic
C	Forward gain compared to average gain over the entire hemisphere
D	Forward gain compared to the gain in the reverse direction

Figure E7-2