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

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1. - E0A08

What does SAR measure?

Select	Answer
A	The rate of RF energy reflected from stationary terrain
B	Signal Amplification Rating
C	The rate at which RF energy is absorbed by the body
D	Synthetic Aperture Ratio of the human body

2. - E1A06

Where must the carrier frequency of a CW signal be set to comply with FCC rules for 60 meter operation?

Select	Answer
A	On any frequency where the signal's sidebands are within the channel
B	At the lowest frequency of the channel
C	At the center frequency of the channel
D	At the highest frequency of the channel

3. - E1B03

Within what distance must an amateur station protect an FCC monitoring facility from harmful interference?

Select	Answer
A	30 miles
B	1 mile
C	3 miles
D	10 miles

4. - E1C02

Which of the following types of communications may be transmitted to amateur stations in foreign countries?

Select	Answer
A	Business-related messages for non-profit organizations
B	All these choices are correct
C	Communications incidental to the purpose of the amateur service and remarks of a personal nature
D	Messages intended for users of the maritime satellite service

5. - E1D07

Which HF amateur bands have frequencies authorized for space stations?

Select	Answer
A	Only the 40, 20, 17, 15, and 10 meter bands
B	Only the 40, 30, 20, 15, 12, and 10 meter bands
C	Only the 40, 20, 17, 15, 12, and 10 meter bands
D	All HF bands

6. - E1E05

What is the minimum passing score on all amateur operator license examinations?

Select	Answer
A	Minimum passing score of 74%
B	Minimum passing score of 77%
C	Minimum passing score of 80%
D	Minimum passing score of 70%

7. - E1F02

What privileges are authorized in the U.S. to persons holding an amateur service license granted by the government of Canada?

Select	Answer
A	All privileges of the Amateur Extra Class license
B	The operating terms and conditions of the Canadian amateur service license, not to exceed U.S. Amateur Extra Class license privileges
C	None, they must obtain a U.S. license
D	Full privileges, up to and including those of the Amateur Extra Class license, on the 80, 40, 20, 15, and 10 meter bands

8. - E2A12

What is the purpose of digital store-and-forward functions on an amateur radio satellite?

Select	Answer
A	To store digital messages in the satellite for later download by other stations
B	To relay messages between satellites
C	To upload operational software for the transponder
D	To delay download of telemetry between satellites

9. - E2B11

What is the function of the Vertical Interval Signaling (VIS) code sent as part of an SSTV transmission?

Select	Answer
A	To lock the color burst oscillator in color SSTV images
B	To identify the call sign of the station transmitting
C	To identify the SSTV mode being used
D	To provide vertical synchronization

10. - E2C09

What type of equipment is commonly used to implement an amateur radio mesh network?

Select	Answer
A	A 440 MHz transceiver with a 9600 baud modem
B	A wireless router running custom firmware
C	An optical cable connection between the USB ports of 2 separate computers
D	A 2 meter VHF transceiver with a 1200 baud modem

11. - E2D11

Which of the following data are used by the APRS network to communicate station location?

Select	Answer
A	Time and frequency
B	Polar coordinates
C	Radio direction finding spectrum analysis
D	Latitude and longitude

12. - E2E03

How is the timing of FT4 contacts organized?

Select	Answer
A	Alternating transmissions at 7.5 second intervals
B	By exchanging ACK/NAK packets
C	Stations take turns on alternate days
D	It depends on the lunar phase

13. - E3A13

Which of these emission modes is best for auroral propagation?

Select	Answer
A	RTTY
B	CW
C	FM
D	SSB

14. - E3B05

Which amateur bands typically support long-path propagation?

Select	Answer
A	160 meters to 10 meters
B	Only 160 meters to 40 meters
C	Only 30 meters to 10 meters
D	6 meters to 2 meters

15. - E3C13

What type of polarization is best for ground-wave propagation?

Select	Answer
A	Vertical
B	Elliptical
C	Circular
D	Horizontal

16. - E4A02

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

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

17. - E4B10

Which of the following methods measures intermodulation distortion in an SSB transmitter?

Select	Answer
A	Modulate the transmitter using two RF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer
B	Modulate the transmitter using two AF signals having harmonically related frequencies and observe the RF output with a peak reading wattmeter
C	Modulate the transmitter using two RF signals having harmonically related frequencies and observe the RF output with a logic analyzer
D	Modulate the transmitter using two AF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer

18. - E4C05

What does a receiver noise floor of -174 dBm represent?

Select	Answer
A	The theoretical noise in a 1 Hz bandwidth at the input of a perfect receiver at room temperature
B	The noise figure of a 1 Hz bandwidth receiver
C	The minimum detectable signal as a function of receive frequency
D	The galactic noise contribution to minimum detectable signal

19. - E4D06

What is the term for spurious signals generated by the combination of two or more signals in a non-linear device or circuit?

Select	Answer
A	Intermodulation
B	Neutralization
C	Amplifier desensitization
D	Adjacent channel interference

20. - E4E09

What undesirable effect can occur when using an IF noise blanker?

Select	Answer
A	FM signals can no longer be demodulated
B	The audio frequency bandwidth of the received signal might be compressed
C	Received audio in the speech range might have an echo effect
D	Nearby signals may appear to be excessively wide even if they meet emission standards

21. - E5A08

What is the phase relationship between the current through and the voltage across a series resonant circuit at resonance?

Select	Answer
A	The voltage leads the current by 90 degrees
B	The voltage and current are in phase
C	The voltage and current are 180 degrees out of phase
D	The current leads the voltage by 90 degrees

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

23. - E5C05

What is the name of the diagram used to show the phase relationship between impedances at a given frequency?

Select	Answer
A	Phasor diagram
B	Far field diagram
C	Venn diagram
D	Near field diagram

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

25. - E6A07

Which of the following indicates that a silicon NPN junction transistor is biased on?

Select	Answer
A	Base-to-emitter voltage of approximately 6 to 7 volts
B	Base-to-emitter voltage of approximately 0.6 to 0.7 volts
C	Base-to-emitter resistance of approximately 6 to 7 ohms
D	Base-to-emitter resistance of approximately 0.6 to 0.7 ohms

26. - E6B06

Which of the following is a common use of a Schottky diode?

Select	Answer
A	As a rectifier in high current power supplies
B	As a constant voltage reference in a power supply
C	As a VHF/UHF mixer or detector
D	As a variable capacitance in an automatic frequency control circuit

27. - E6C11

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

Select	Answer
A	4
B	5
C	6
D	2

28. - E6D08

What is one reason for using powdered-iron cores rather than ferrite cores in an inductor?

Select	Answer
A	Powdered-iron cores generally have greater initial permeability
B	Powdered-iron cores use smaller diameter wire for the same inductance
C	Powdered-iron cores generally require fewer turns to produce a given inductance
D	Powdered-iron cores generally maintain their characteristics at higher currents

29. - E6E04

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

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

30. - E6F05

Which describes an optical shaft encoder?

Select	Answer
A	A device that detects rotation of a control by interrupting a light source with a patterned wheel
B	A device that measures the strength of a beam of light using analog to digital conversion
C	A digital encryption device often used to encrypt spacecraft control signals
D	A device for generating RTTY signals by means of a rotating light source

31. - E7A10

What is a truth table?

Select	Answer
A	A table of logic symbols that indicate the high logic states of an op-amp
B	A table of logic symbols that indicate the logic states of an op-amp
C	A diagram showing logic states when the digital device output is true
D	A list of inputs and corresponding outputs for a digital device

32. - E7B04

Where on the load line of a Class A common emitter amplifier would bias normally be set?

Select	Answer
A	At a point where the bias resistor equals the load resistor
B	Where the load line intersects the voltage axis
C	Approximately halfway between saturation and cutoff
D	At a point where the load line intersects the zero bias current curve

33. - E7C09

What is a crystal lattice filter?

Select	Answer
A	A filter using lattice-shaped quartz crystals for high-Q performance
B	A power supply filter made with interlaced quartz crystals
C	A filter with narrow bandwidth and steep skirts made using quartz crystals
D	An audio filter made with four quartz crystals that resonate at 1 kHz intervals

34. - E7D14

What is the purpose of connecting equal-value resistors across power supply filter capacitors connected in series?

Select	Answer
A	Discharge the capacitors when voltage is removed
B	Equalize the voltage across each capacitor
C	Provide a minimum load on the supply
D	All these choices are correct

35. - E7E05

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

Select	Answer
A	A heterodyne suppressor
B	A pre-emphasis network
C	A heterodyne enhancer
D	A de-emphasis network

36. - E7F14

Which of the following would allow a digital signal processing filter to create a sharper filter response?

Select	Answer
A	Higher data rate
B	Complex phasor representations
C	Double-precision math routines
D	More taps

37. - E7G08

How does the gain of an ideal operational amplifier vary with frequency?

Select	Answer
A	It decreases logarithmically with increasing frequency
B	It decreases linearly with increasing frequency
C	It does not vary with frequency
D	It increases linearly with increasing frequency

38. - E7H01

What are three oscillator circuits used in amateur radio equipment?

Select	Answer
A	Taft, Pierce and negative feedback
B	Colpitts, Hartley and Pierce
C	Pierce, Fenner and Beane
D	Taft, Hartley and Pierce

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	25 to 1
C	100 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 increases as the RF carrier frequency increases
B	It does not depend on the RF carrier frequency
C	It decreases as the RF carrier frequency increases
D	It varies with the square root of the RF carrier frequency

41. - E8C01

How is Forward Error Correction implemented?

Select	Answer
A	By varying the frequency shift of the transmitted signal according to a predefined algorithm
B	By transmitting extra data that may be used to detect and correct transmission errors
C	By the receiving station repeating each block of three data characters
D	By transmitting a special algorithm to the receiving station along with the data characters

42. - E8D06

What is the advantage of including parity bits in ASCII characters?

Select	Answer
A	Some types of errors can be detected
B	The signal can overpower interfering signals
C	Faster transmission rate
D	Foreign language characters can be sent

43. - E9A01

What is an isotropic antenna?

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

44. - E9B08

What is the far field of an antenna?

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

45. - E9C11

How is the far-field elevation pattern of a vertically polarized antenna affected by being mounted over seawater versus soil?

Select	Answer
A	The low-angle radiation decreases
B	Additional higher vertical angle lobes will appear
C	Fewer vertical angle lobes will be present
D	The low-angle radiation increases

46. - E9D10

What happens to feed-point impedance at the base of a fixed length HF mobile antenna when operated below its resonant frequency?

Select	Answer
A	The radiation resistance decreases and the capacitive reactance increases
B	The radiation resistance decreases and the capacitive reactance decreases
C	The radiation resistance increases and the capacitive reactance increases
D	The radiation resistance increases and the capacitive reactance decreases

47. - E9E04

What is the purpose of the series capacitor in a gamma-type antenna matching network?

Select	Answer
A	To transform the antenna impedance to a higher value
B	To cancel the inductive reactance of the matching network
C	To provide a rejection notch that prevents the radiation of harmonics
D	To provide DC isolation between the feed line and the antenna

48. - E9F08

Which of the following is a significant difference between foam dielectric coaxial cable and solid dielectric cable, assuming all other parameters are the same?

Select	Answer
A	All these choices are correct
B	Foam dielectric has lower safe operating voltage limits
C	Foam dielectric has higher velocity factor
D	Foam dielectric has lower loss per unit of length

49. - E9G11

How are the wavelength scales on a Smith chart calibrated?

Select	Answer
A	In fractions of transmission line electrical frequency
B	In fractions of antenna electrical frequency
C	In fractions of transmission line electrical wavelength
D	In fractions of antenna electrical wavelength

50. - E9H09

What is a Pennant antenna?

Select	Answer
A	A small, vertically oriented receiving antenna consisting of a triangular loop terminated in approximately 900 ohms
B	A four-element, high-gain vertical array invented by George Pennant
C	A stealth antenna built to look like a flagpole
D	A form of rhombic antenna terminated in a variable capacitor to provide frequency diversity

Figure E6-3