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

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1. - E0A04

When evaluating a site with multiple transmitters operating at the same time, the operators and licensees of which transmitters are responsible for mitigating over-exposure situations?

Select	Answer
A	Each transmitter that produces 5 percent or more of its MPE limit in areas where the total MPE limit is exceeded.
B	Each transmitter operating with a duty cycle greater than 50 percent
C	Only commercial transmitters
D	Only the most powerful transmitter

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	18.107 MHz
B	18.068 MHz
C	18.110 MHz
D	18.100 MHz

3. - E1B09

Which amateur stations may be operated under RACES rules?

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

4. - E1C12

On what portion of the 630 meter band are phone emissions permitted?

Select	Answer
A	The entire band
B	Only the bottom 3 kHz
C	Only the top 3 kHz
D	None

5. - E1D03

What is a space telecommand station?

Select	Answer
A	An amateur station located in a satellite or a balloon more than 50 kilometers above the surface of the Earth
B	An amateur station that transmits communications to initiate, modify or terminate functions of a space station
C	An amateur station that receives telemetry from a satellite or balloon more than 50 kilometers above the surface of the Earth
D	An amateur station located on the surface of the Earth for communication with other Earth stations by means of Earth satellites

6. - E1E05

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

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

7. - E1F08

Which of the following types of amateur station communications are prohibited?

Select	Answer
A	Communications in a language other than English
B	Communications transmitted for hire or material compensation, except as otherwise provided in the rules
C	Communications that have political content, except as allowed by the Fairness Doctrine
D	Communications that have religious content

8. - E2A09

What do the terms L band and S band specify regarding satellite communications?

Select	Answer
A	The 2 meter and 70 centimeter bands
B	FM and Digital Store-and-Forward systems
C	Which sideband to use
D	The 23 centimeter and 13 centimeter bands

9. - E2B07

What is the name of the signal component that carries color information in NTSC video?

Select	Answer
A	Chroma
B	Spectral intensity
C	Hue
D	Luminance

10. - E2C12

What technique do individual nodes use to form a mesh network?

Select	Answer
A	Discovery and link establishment protocols
B	Forward error correction and Viterbi codes
C	Custom code plugs for the local trunking systems
D	Acting as store-and-forward digipeaters

11. - E2D04

What technology is used to track, in real time, balloons carrying amateur radio transmitters?

Select	Answer
A	Bandwidth compressed LORAN
B	APRS
C	Doppler shift of beacon signals
D	Ultrasonics

12. - E2E01

Which of the following types of modulation is common for data emissions below 30 MHz?

Select	Answer
A	FSK
B	DTMF tones modulating an FM signal
C	Spread spectrum
D	Pulse modulation

13. - E3A13

Which of these emission modes is best for auroral propagation?

Select	Answer
A	RTTY
B	SSB
C	CW
D	FM

14. - E3B05

Which amateur bands typically support long-path propagation?

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

15. - E3C01

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

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

16. - E4A09

Which of the following is good practice when using an oscilloscope probe?

Select	Answer
A	Never use a high-impedance probe to measure a low-impedance circuit
B	Keep the signal ground connection of the probe as short as possible
C	Never use a DC-coupled probe to measure an AC circuit
D	All these choices are correct

17. - E4B07

What do the subscripts of S parameters represent?

Select	Answer
A	The relative time between measurements
B	Relative quality of the data
C	Frequency order of the measurements
D	The port or ports at which measurements are made

18. - E4C13

How does a narrow-band roofing filter affect receiver performance?

Select	Answer
A	It improves intelligibility by using low Q circuitry to reduce ringing
B	All these choices are correct
C	It improves dynamic range by attenuating strong signals near the receive frequency
D	It improves sensitivity by reducing front end noise

19. - E4D10

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

Select	Answer
A	Signals less than 40 dBm will not generate audible third-order intermodulation products
B	A 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
C	The receiver can tolerate signals up to 40 dB above the noise floor without producing third-order intermodulation products
D	A pair of 1 mW input signals will produce a third-order intermodulation product that is 40 dB stronger than the input signal

20. - E4E02

Which of the following types of noise can often be reduced with a digital signal processing noise filter?

Select	Answer
A	Broadband white noise
B	Power line noise
C	All these choices are correct
D	Ignition noise

21. - E5A15

Which of the following increases Q for inductors and capacitors?

Select	Answer
A	Lower reactance
B	Higher self-resonant frequency
C	Lower losses
D	Lower self-resonant frequency

22. - E5B03

How is impedance in polar form converted to an equivalent admittance?

Select	Answer
A	Take the reciprocal of the magnitude and change the sign of the angle
B	Take the square root of the magnitude and add 180 degrees to the angle
C	Take the reciprocal of the angle and change the sign of the magnitude
D	Square the magnitude and subtract 90 degrees from the angle

23. - E5C08

What coordinate system is often used to display the phase angle of a circuit containing resistance, inductive and/or capacitive reactance?

Select	Answer
A	Elliptical coordinates
B	Faraday grid
C	Polar coordinates
D	Maidenhead grid

24. - E5D01

What is the result of skin effect?

Select	Answer
A	As frequency increases, RF current flows in a thinner layer of the conductor, closer to the surface
B	Thermal effects on the surface of the conductor decrease the impedance
C	Thermal effects on the surface of the conductor increase the impedance
D	As frequency decreases, RF current flows in a thinner layer of the conductor, closer to the surface

25. - E6A05

How does DC input impedance at the gate of a field-effect transistor compare with the DC input impedance of a bipolar transistor?

Select	Answer
A	They are both low impedance
B	They are both high impedance
C	An FET has higher input impedance
D	An FET has lower input impedance

26. - E6B04

What type of semiconductor device is designed for use as a voltage-controlled capacitor?

Select	Answer
A	Zener diode
B	Silicon-controlled rectifier
C	Tunnel diode
D	Varactor diode

27. - E6C02

What happens when the level of a comparator's input signal crosses the threshold?

Select	Answer
A	The comparator enters latch-up
B	The feedback loop becomes unstable
C	The IC input can be damaged
D	The comparator changes its output state

28. - E6D05

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

Select	Answer
A	Ferrite toroids are easier to use with surface mount technology
B	Ferrite toroids generally have better temperature stability
C	Ferrite toroids generally require fewer turns to produce a given inductance value
D	Ferrite toroids generally have lower initial permeability

29. - E6E09

Which of the following component package types would be most suitable for use at frequencies above the HF range?

Select	Answer
A	Radial lead
B	TO-220
C	Surface mount
D	Axial lead

30. - E6F04

What is the photovoltaic effect?

Select	Answer
A	The conversion of electrical energy to mechanical energy
B	The conversion of light to electrical energy
C	The conversion of voltage to current when exposed to light
D	The tendency of a battery to discharge when exposed to light

31. - E7A10

What is a truth table?

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

32. - E7B10

In Figure E7-1, what is the purpose of R1 and R2?

Select	Answer
A	Feedback
B	Self bias
C	Voltage divider bias
D	Load resistors

33. - E7C01

How are the capacitors and inductors of a low-pass filter Pi-network arranged between the network's input and output?

Select	Answer
A	A capacitor is connected between the input and ground, another capacitor is connected between the output and ground, and an inductor is connected between input and output
B	Two capacitors are in series between the input and output, and an inductor is connected between the two capacitors and ground
C	Two inductors are in series between the input and output, and a capacitor is connected between the two inductors and ground
D	An inductor is connected between the input and ground, another inductor is connected between the output and ground, and a capacitor is connected between the input and output

34. - E7D11

What is the function of the pass transistor in a linear voltage regulator circuit?

Select	Answer
A	Maintains nearly constant output voltage over a wide range of load current
B	Maintains nearly constant output impedance over a wide range of load current
C	Permits a wide range of output voltage settings
D	Provides a stable input impedance over a wide range of source voltage

35. - E7E08

What are the principal frequencies that appear at the output of a mixer circuit?

Select	Answer
A	The two input frequencies along with their sum and difference frequencies
B	The square root of the product of input frequencies
C	Two and four times the original frequency
D	1.414 and 0.707 times the input frequency

36. - E7F05

How frequently must an analog signal be sampled by an analog-to-digital converter so that the signal can be accurately reproduced?

Select	Answer
A	At the same rate as the highest frequency component of the signal
B	At least twice the rate of the highest frequency component of the signal
C	At least half the rate of the highest frequency component of the signal
D	At four times the rate of the highest frequency component of the signal

37. - E7G09

What will be the output voltage of the circuit shown in Figure E7-3 if R1 is 1000 ohms, RF is 10,000 ohms, and 0.23 volts DC is applied to the input?

Select	Answer
A	-2.3 volts
B	2.3 volts
C	-0.23 volts
D	0.23 volts

38. - E7H11

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

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

39. - E8A01

What is the name of the process that shows that a square wave is made up of a sine wave plus all its odd harmonics?

Select	Answer
A	Numerical analysis
B	Differential analysis
C	Vector analysis
D	Fourier analysis

40. - E8B04

What is the modulation index of an FM-phone signal having a maximum carrier deviation of plus or minus 6 kHz when modulated with a 2 kHz modulating frequency?

Select	Answer
A	2000
B	1/3
C	3
D	6000

41. - E8C03

Why should phase-shifting of a PSK signal be done at the zero crossing of the RF signal?

Select	Answer
A	All these choices are correct
B	To improve carrier suppression
C	To simplify modulation
D	To minimize bandwidth

42. - E8D04

What is the primary effect of extremely short rise or fall time on a CW signal?

Select	Answer
A	The generation of key clicks
B	The generation of RF harmonics
C	Limits data speed
D	More difficult to copy

43. - E9A04

Which of the following factors affect the feed point impedance of an antenna?

Select	Answer
A	Transmission line length
B	Antenna height
C	The settings of an antenna tuner at the transmitter
D	The input power level

44. - E9B05

What type of antenna pattern is shown in Figure E9-2?

Select	Answer
A	Elevation
B	Polarization
C	Radiation resistance
D	Azimuth

45. - E9C02

What is the radiation pattern of two 1/4-wavelength vertical antennas spaced 1/4 wavelength apart and fed 90 degrees out of phase?

Select	Answer
A	Omni-directional
B	A figure-8 broadside to the axis of the array
C	A figure-8 end-fire along the axis of the array
D	Cardioid

46. - E9D11

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

Select	Answer
A	Resistive wire, such as spark plug wire
B	Solid wire
C	Wide flat copper strap
D	Stranded wire

47. - E9E06

Which of these feed line impedances would be suitable for constructing a quarter-wave Q-section for matching a 100-ohm loop to 50-ohm feed line?

Select	Answer
A	75 ohms
B	62 ohms
C	450 ohms
D	50 ohms

48. - E9F10

What impedance does a 1/8-wavelength transmission line present to a generator when the line is shorted at the far end?

Select	Answer
A	An inductive reactance
B	A capacitive reactance
C	The same as the characteristic impedance of the line
D	Zero

49. - E9G10

What do the arcs on a Smith chart represent?

Select	Answer
A	Points with constant resistance
B	Points with constant reactance
C	SWR
D	Frequency

50. - E9H06

What is the triangulation method of direction finding?

Select	Answer
A	The geometric angles of sky waves from the source are used to determine its position
B	A fixed receiving station uses three different antennas to plot the location of the signal source
C	Antenna headings from several different receiving locations are used to locate the signal source
D	A fixed receiving station plots three headings to the signal source

Figure E7-1

Figure E7-3

Figure E9-2