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

2. - E1A08

If a station in a message forwarding system inadvertently forwards a message that is in violation of FCC rules, who is primarily accountable for the rules violation?

Select	Answer
A	The control operators of all the stations in the system
B	The control operator of the packet bulletin board station
C	The control operator of the originating station
D	The control operators of all the stations in the system not authenticating the source from which they accept communications

3. - E1B10

What frequencies are authorized to an amateur station operating under RACES rules?

Select	Answer
A	Military Auxiliary Radio System (MARS) channels
B	All amateur service frequencies authorized to the control operator
C	Specific segments in the amateur service MF, HF, VHF and UHF bands
D	Specific local government channels

4. - E1C10

What is the permitted mean power of any spurious emission relative to the mean power of the fundamental emission from a station transmitter or external RF amplifier installed after January 1, 2003 and transmitting on a frequency below 30 MHz?

Select	Answer
A	At least 53 dB below
B	At least 43 dB below
C	At least 73 dB below
D	At least 63 dB below

5. - E1D01

What is the definition of telemetry?

Select	Answer
A	One-way transmission of measurements at a distance from the measuring instrument
B	Two-way transmissions of data
C	Two-way transmissions in excess of 1000 feet
D	One-way transmission that initiates, modifies, or terminates the functions of a device at a distance

6. - E1E02

Who does Part 97 task with maintaining the pools of questions for all U.S. amateur license examinations?

Select	Answer
A	The VECs
B	The FCC
C	The ARRL
D	The VEs

7. - E1F05

Amateur stations may not transmit in which of the following frequency segments if they are located in the contiguous 48 states and north of Line A?

Select	Answer
A	440 MHz - 450 MHz
B	420 MHz - 430 MHz
C	222 MHz - 223 MHz
D	53 MHz - 54 MHz

8. - E2A01

What is the direction of an ascending pass for an amateur satellite?

Select	Answer
A	From west to east
B	From north to south
C	From south to north
D	From east to west

9. - E2B08

What technique allows commercial analog TV receivers to be used for fast-scan TV operations on the 70 cm band?

Select	Answer
A	Transmitting on channels shared with cable TV
B	Using USB and demodulating the signal with a computer sound card
C	Using converted satellite TV dishes
D	Transmitting on the abandoned TV channel 2

10. - E2C08

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

Select	Answer
A	Contacts between a U.S. station and a non-U.S. station
B	Contacts using tactical call signs
C	Special event contacts between stations in the U.S.
D	Repeater contacts between U.S. club members

11. - E2D03

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

Select	Answer
A	MSK144
B	Olivia
C	PACTOR III
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. - E3A03

When scheduling EME contacts, which of these conditions will generally result in the least path loss?

Select	Answer
A	When the MUF is above 30 MHz
B	When the moon is at apogee
C	When the moon is at perigee
D	When the moon is full

14. - E3B06

Which of the following amateur bands most frequently provides long-path propagation?

Select	Answer
A	20 meters
B	80 meters
C	6 meters
D	10 meters

15. - E3C02

What is indicated by a rising A or K index?

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

16. - E4A06

What is the effect of aliasing on a digital oscilloscope caused by setting the time base too slow?

Select	Answer
A	A false, jittery low-frequency version of the signal is displayed
B	Calibration of the vertical scale is no longer valid
C	Excessive blanking occurs, which prevents display of the signal
D	All signals will have a DC offset

17. - E4B11

Which of the following can be measured with a vector network analyzer?

Select	Answer
A	All these choices are correct
B	Input impedance
C	Reflection coefficient
D	Output impedance

18. - E4C08

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

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

19. - E4D09

What is the purpose of the preselector in a communications receiver?

Select	Answer
A	To store often-used frequencies
B	To allow selection of the optimum RF amplifier device
C	To increase rejection of signals outside the desired band
D	To provide a range of AGC time constants

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

21. - E5A05

What is the result of increasing the Q of an impedance-matching circuit?

Select	Answer
A	It has no effect on impedance matching
B	Matching bandwidth is decreased
C	Matching bandwidth is increased
D	Matching range is increased

22. - E5B11

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 25 ohms, R is 100 ohms, and XL is 50 ohms?

Select	Answer
A	76 degrees with the voltage lagging the current
B	76 degrees with the voltage leading the current
C	14 degrees with the voltage leading the current
D	14 degrees with the voltage lagging 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	Near field diagram
B	Far field diagram
C	Phasor diagram
D	Venn diagram

24. - E5D04

Why are short connections used at microwave frequencies?

Select	Answer
A	To increase compensating capacitance
B	To reduce noise figure
C	To reduce phase shift along the connection
D	To increase neutralizing resistance

25. - E6A03

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

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

26. - E6B02

What is an important characteristic of a Schottky diode as compared to an ordinary silicon diode when used as a power supply rectifier?

Select	Answer
A	Much higher reverse voltage breakdown
B	More constant reverse avalanche voltage
C	Less forward voltage drop
D	Longer carrier retention time

27. - E6C02

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

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

28. - E6D12

What is inductor saturation?

Select	Answer
A	The ability of the inductor's core to store magnetic energy has been exceeded
B	The inductor's voltage rating is exceeded causing a flashover
C	Adjacent inductors become over-coupled
D	The inductor windings are over-coupled

29. - E6E06

What characteristics of the MMIC make it a popular choice for VHF through microwave circuits?

Select	Answer
A	Controlled gain, low noise figure, and constant input and output impedance over the specified frequency range
B	Nearly infinite gain, very high input impedance, and very low output impedance
C	Plate current that is controlled by a control grid
D	The ability to retrieve information from a single signal even in the presence of other strong signals

30. - E6F06

Which of these materials is most commonly used to create photoconductive devices?

Select	Answer
A	A crystalline semiconductor
B	A liquid semiconductor
C	An ordinary metal
D	A heavy metal

31. - E7A08

What logical operation does an OR gate perform?

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

32. - E7B14

Why are switching amplifiers more efficient than linear amplifiers?

Select	Answer
A	Switching amplifiers operate at higher voltages
B	The power transistor is at saturation or cutoff most of the time
C	Switching amplifiers use push-pull circuits
D	Linear amplifiers have high gain resulting in higher harmonic content

33. - E7C04

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

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

34. - E7D02

What is a characteristic of a switching electronic voltage regulator?

Select	Answer
A	It gives a ramp voltage at its output
B	The controlled device's duty cycle is changed to produce a constant average output voltage
C	The resistance of a control element is varied in direct proportion to the line voltage or load current
D	It is generally less efficient than a linear regulator

35. - E7E02

What is the function of a reactance modulator?

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

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	An adaptive filter
D	A Hilbert-transform filter

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?

Select	Answer
A	24
B	47
C	0.21
D	94

38. - E7H12

Which of the following must be done to ensure that a crystal oscillator provides the frequency specified by the crystal manufacturer?

Select	Answer
A	Provide the crystal with a specified parallel inductance
B	Bias the crystal at a specified current
C	Provide the crystal with a specified parallel capacitance
D	Bias the crystal at a specified voltage

39. - E8A03

What type of wave does a Fourier analysis show to be made up of sine waves of a given fundamental frequency plus all its harmonics?

Select	Answer
A	A sine wave
B	A sawtooth wave
C	A square wave
D	A cosine wave

40. - E8B03

What is the modulation index of an FM-phone signal having a maximum frequency deviation of 3000 Hz either side of the carrier frequency when the modulating frequency is 1000 Hz?

Select	Answer
A	0.3
B	3
C	3000
D	1000

41. - E8C06

What is the bandwidth of a 170-hertz shift, 300-baud ASCII transmission?

Select	Answer
A	0.3 kHz
B	0.1 Hz
C	1.0 kHz
D	0.5 kHz

42. - E8D01

Why are received spread spectrum signals resistant to interference?

Select	Answer
A	Signals not using the spread spectrum algorithm are suppressed in the receiver
B	The high power used by a spread spectrum transmitter keeps its signal from being easily overpowered
C	If interference is detected by the receiver it will signal the transmitter to change frequencies
D	The receiver is always equipped with a digital blanker

43. - E9A04

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

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

44. - E9B09

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

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

45. - E9C06

What is the effect of adding a terminating resistor to a rhombic antenna?

Select	Answer
A	It changes the radiation pattern from horizontal to vertical polarization
B	It changes the radiation pattern from bidirectional to unidirectional
C	It decreases the ground loss
D	It reflects the standing waves on the antenna elements back to the transmitter

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

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?

Select	Answer
A	The stub match
B	The omega match
C	The gamma match
D	The delta match

48. - E9F05

What is the approximate physical length of a solid polyethylene dielectric coaxial transmission line that is electrically 1/4 wavelength long at 14.1 MHz?

Select	Answer
A	4.3 meters
B	5.3 meters
C	3.5 meters
D	10.6 meters

49. - E9G07

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

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

50. - E9H03

What is Receiving Directivity Factor (RDF)?

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

Figure E9-3