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

Logging in (or registering) will help the system to select questions that you need to focus on.

1. - E0A02

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

Select	Answer
A	Ensure signals from your station are less than the controlled Maximum Permitted Emission (MPE) limits
B	Ensure signals from your station are less than the controlled Maximum Permitted Exposure (MPE) limits
C	Ensure signals from your station are less than the uncontrolled Maximum Permitted Emission (MPE) limits
D	Ensure signals from your station are less than the uncontrolled Maximum Permitted Exposure (MPE) limits

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	18.068 MHz
B	18.100 MHz
C	18.110 MHz
D	18.107 MHz

3. - E1B12

What must the control operator of a repeater operating in the 70 cm band do if a radiolocation system experiences interference from that repeater?

Select	Answer
A	File an FAA NOTAM (Notice to Airmen) with the repeater system's ERP, call sign, and six-character grid locator
B	Cease operation or make changes to the repeater to mitigate the interference
C	All these choices are correct
D	Reduce the repeater antenna HAAT (Height Above Average Terrain)

4. - E1C05

When may an automatically controlled station originate third party communications?

Select	Answer
A	Never
B	When agreed upon by the sending or receiving station
C	Only when transmitting RTTY or data emissions
D	When approved by the National Telecommunication and Information Administration

5. - E1D12

Which of the following amateur stations may transmit one-way communications?

Select	Answer
A	A message forwarding station or automatically controlled digital station
B	All these choices are correct
C	A space station, beacon station, or telecommand station
D	A local repeater or linked repeater station

6. - E1E03

What is a Volunteer Examiner Coordinator?

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

7. - E1F10

Who may be the control operator of an auxiliary station?

Select	Answer
A	Only Amateur Extra Class operators
B	Only Technician, General, Advanced or Amateur Extra Class operators
C	Any licensed amateur operator
D	Only General, Advanced or Amateur Extra Class operators

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 circularly polarized antenna
D	A log-periodic dipole array

9. - E2B02

How many horizontal lines make up a fast-scan (NTSC) television frame?

Select	Answer
A	1080
B	525
C	30
D	60

10. - E2C01

What indicator is required to be used by U.S.-licensed operators when operating a station via remote control and the remote transmitter is located in the U.S.?

Select	Answer
A	/ followed by the USPS two-letter abbreviation for the state in which the remote station is located
B	/ followed by the ARRL Section of the remote station
C	/R# where # is the district of the remote station
D	No additional indicator is required

11. - E2D03

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

Select	Answer
A	Olivia
B	PACTOR III
C	MSK144
D	JT65

12. - E2E11

What is the difference between direct FSK and audio FSK?

Select	Answer
A	Direct FSK occupies less bandwidth
B	Direct FSK applies the data signal to the transmitter VFO, while AFSK transmits tones via phone
C	Direct FSK can transmit faster baud rates
D	Only direct FSK can be decoded by computer

13. - E3A04

What do Hepburn maps predict?

Select	Answer
A	Sporadic E propagation
B	Probability of tropospheric propagation
C	Locations of auroral reflecting zones
D	Likelihood of rain scatter along cold or warm fronts

14. - E3B11

At what time of day can sporadic E propagation occur?

Select	Answer
A	Any time
B	Only in hours of darkness
C	Only around sunset and sunrise
D	Only around sunset

15. - E3C01

What does the radio communication term "ray tracing" describe?

Select	Answer
A	Modeling a radio wave's path through the ionosphere
B	The process in which an electronic display presents a pattern
C	Determining the radiation pattern from an array of antennas
D	Evaluating high voltage sources for x-rays

16. - E4A05

What is the purpose of the prescaler function on a frequency counter?

Select	Answer
A	It amplifies low-level signals for more accurate counting
B	It prevents oscillation in a low-frequency counter circuit
C	It multiplies a higher frequency signal so a low-frequency counter can display the operating frequency
D	It divides a higher frequency signal so a low-frequency counter can display the input frequency

17. - E4B09

What is indicated if the current reading on an RF ammeter placed in series with the antenna feed line of a transmitter increases as the transmitter is tuned to resonance?

Select	Answer
A	The transmitter is not properly neutralized
B	There is more power going into the antenna
C	There is possibly a short to ground in the feed line
D	There is an impedance mismatch between the antenna and feed line

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?

Select	Answer
A	The attenuator has a low-pass filter to increase the strength of lower frequency signals
B	Atmospheric noise is generally greater than internally generated noise even after attenuation
C	Signals are attenuated separately from the noise
D	The attenuator has a noise filter to suppress interference

19. - E4D07

Which of the following reduces the likelihood of receiver desensitization?

Select	Answer
A	Decrease the RF bandwidth of the receiver
B	Switch from fast AGC to slow AGC
C	Increase the receiver front end gain
D	Raise the receiver IF frequency

20. - E4E03

Which of the following signals might a receiver noise blanker be able to remove from desired signals?

Select	Answer
A	Signals that appear across a wide bandwidth
B	Signals that appear at one IF but not another
C	Signals that are constant at all IF levels
D	Signals that have a sharply peaked frequency distribution

21. - E5A16

What is the resonant frequency of an RLC circuit if R is 33 ohms, L is 50 microhenries and C is 10 picofarads?

Select	Answer
A	7.12 MHz
B	23.5 MHz
C	23.5 kHz
D	7.12 kHz

22. - E5B08

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 100 ohms, R is 100 ohms, and XL is 75 ohms?

Select	Answer
A	14 degrees with the voltage lagging the current
B	76 degrees with the voltage lagging the current
C	14 degrees with the voltage leading the current
D	76 degrees with the voltage leading the current

23. - E5C03

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

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

24. - E5D09

What happens to reactive power in an AC circuit that has both ideal inductors and ideal capacitors?

Select	Answer
A	It is dissipated as heat in the circuit
B	It is dissipated as kinetic energy in the circuit
C	It is repeatedly exchanged between the associated magnetic and electric fields, but is not dissipated
D	It is dissipated in the formation of inductive and capacitive fields

25. - E6A08

What term indicates the frequency at which the grounded-base current gain of a transistor has decreased to 0.7 of the gain obtainable at 1 kHz?

Select	Answer
A	Corner frequency
B	Alpha cutoff frequency
C	Alpha rejection frequency
D	Beta cutoff frequency

26. - E6B09

What is a common use for point-contact diodes?

Select	Answer
A	As a constant current source
B	As an RF detector
C	As a high-voltage rectifier
D	As a constant voltage source

27. - E6C10

In Figure E6-3, what is the schematic symbol for a NOR gate?

Select	Answer
A	1
B	4
C	2
D	3

28. - E6D06

What core material property determines the inductance of an inductor?

Select	Answer
A	Resistance
B	Reactivity
C	Thermal impedance
D	Permeability

29. - E6E01

Why is gallium arsenide (GaAs) useful for semiconductor devices operating at UHF and higher frequencies?

Select	Answer
A	Higher electron mobility
B	Lower junction voltage drop
C	Lower transconductance
D	Higher noise figures

30. - E6F03

What is the most common configuration of an optoisolator or optocoupler?

Select	Answer
A	A lens and a photomultiplier
B	An amplitude modulated helium-neon laser
C	A frequency modulated helium-neon laser
D	An LED and a phototransistor

31. - E7A08

What logical operation does an OR gate perform?

Select	Answer
A	It produces logic 1 at its output if all inputs are logic 0
B	It only produces logic 0 at its output when all inputs are logic 1
C	It produces logic 0 at its output if all inputs are logic 1
D	It produces logic 1 at its output if any or all inputs are logic 1

32. - E7B05

What can be done to prevent unwanted oscillations in an RF power amplifier?

Select	Answer
A	Install parasitic suppressors and/or neutralize the stage
B	Tune the stage for maximum SWR
C	Use a phase inverter in the output filter
D	Tune both the input and output for maximum power

33. - E7C04

How does an impedance-matching circuit transform a complex impedance to a resistive impedance?

Select	Answer
A	It introduces transconductance to cancel the reactive part of impedance
B	It cancels the reactive part of the impedance and changes the resistive part to a desired value
C	It introduces negative resistance to cancel the resistive part of impedance
D	Reactive currents are dissipated in matched resistances

34. - E7D06

What is the purpose of Q1 in the circuit shown in Figure E7-2?

Select	Answer
A	It provides D1 with current
B	It provides a constant load for the voltage source
C	It controls the current supplied to the load
D	It provides negative feedback to improve regulation

35. - E7E02

What is the function of a reactance modulator?

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

36. - E7F04

What is a common method of generating an SSB signal using digital signal processing?

Select	Answer
A	Varying quartz crystal characteristics emulated in digital form
B	Signals are combined in quadrature phase relationship
C	A frequency synthesizer removes the unwanted sidebands
D	Mixing products are converted to voltages and subtracted by adder circuits

37. - E7G10

What absolute voltage gain can be expected from the circuit in Figure E7-3 when R1 is 1800 ohms and RF is 68 kilohms?

Select	Answer
A	38
B	1
C	0.03
D	76

38. - E7H11

What are the major spectral impurity components of direct digital synthesizers?

Select	Answer
A	Broadband noise
B	Nyquist limit noise
C	Digital conversion noise
D	Spurious signals at discrete frequencies

39. - E8A06

What is the approximate ratio of PEP-to-average power in a typical single-sideband phone signal?

Select	Answer
A	2.5 to 1
B	100 to 1
C	25 to 1
D	1 to 1

40. - E8B02

How does the modulation index of a phase-modulated emission vary with RF carrier frequency?

Select	Answer
A	It decreases as the RF carrier frequency increases
B	It increases as the RF carrier frequency increases
C	It does not depend on the RF carrier frequency
D	It varies with the square root of the RF carrier frequency

41. - E8C09

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

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

42. - E8D05

What is the most common method of reducing key clicks?

Select	Answer
A	Reduce keying waveform rise and fall times
B	High-pass filters at the transmitter output
C	Low-pass filters at the transmitter output
D	Increase keying waveform rise and fall times

43. - E9A02

What is the effective radiated power relative to a dipole of a repeater station with 150 watts transmitter power output, 2 dB feed line loss, 2.2 dB duplexer loss, and 7 dBd antenna gain?

Select	Answer
A	1977 watts
B	78.7 watts
C	420 watts
D	286 watts

44. - E9B08

What is the far field of an antenna?

Select	Answer
A	The region where radiated power dissipates over a specified time period
B	The region where radiated field strengths are constant
C	The region where the shape of the antenna pattern is independent of distance
D	The region of the ionosphere where radiated power is not refracted

45. - E9C04

What happens to the radiation pattern of an unterminated long wire antenna as the wire length is increased?

Select	Answer
A	The vertical angle increases
B	The front-to-back ratio decreases
C	The lobes align more in the direction of the wire
D	The lobes become more perpendicular to the wire

46. - E9D01

How much does the gain of an ideal parabolic dish antenna change when the operating frequency is doubled?

Select	Answer
A	2 dB
B	6 dB
C	4 dB
D	3 dB

47. - E9E05

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

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

48. - E9F13

What impedance does a 1/4-wavelength transmission line present to a generator when the line is shorted at the far end?

Select	Answer
A	Very high impedance
B	The same as the characteristic impedance of the transmission line
C	The same as the generator output impedance
D	Very low impedance

49. - E9G07

On the Smith chart shown in Figure E9-3, what is the only straight line shown?

Select	Answer
A	The voltage axis
B	The reactance axis
C	The current axis
D	The resistance axis

50. - E9H07

Why is RF attenuation used when direction-finding?

Select	Answer
A	To narrow the receiver bandwidth
B	To prevent receiver overload which reduces pattern nulls
C	To increase receiver sensitivity
D	To compensate for isotropic directivity and the antenna effect of feed lines

Figure E6-3

Figure E7-2

Figure E7-3

Figure E9-3