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

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1. - E0A01

What is the primary function of an external earth connection or ground rod?

Select	Answer
A	Reduce received noise
B	Reduce RF current flow between pieces of equipment
C	Reduce RFI to telephones and home entertainment systems
D	Lightning protection

2. - E1A03

What is the maximum legal carrier frequency on the 20 meter band for transmitting USB AFSK digital signals having a 1 kHz bandwidth?

Select	Answer
A	14.149 MHz
B	14.349 MHz
C	14.100 MHz
D	14.070 MHz

3. - E1B10

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

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

4. - E1C13

What notifications must be given before transmitting on the 630 meter or 2200 meter bands?

Select	Answer
A	An environmental impact statement must be filed with the Department of the Interior
B	Operators must inform the FAA of their intent to operate, giving their call sign and distance to the nearest runway
C	A special endorsement must be requested from the FCC
D	Operators must inform the Utilities Technology Council (UTC) of their call sign and coordinates of the station

5. - E1D03

What is a space telecommand station?

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

6. - E1E01

For which types of out-of-pocket expenses do the Part 97 rules state that VEs and VECs may be reimbursed?

Select	Answer
A	No expenses are authorized for reimbursement
B	Teaching an amateur operator license examination preparation course
C	Providing amateur operator license examination preparation training materials
D	Preparing, processing, administering, and coordinating an examination for an amateur radio operator license

7. - E1F07

When may an amateur station send a message to a business?

Select	Answer
A	When transmitting international third-party communications
B	When neither the amateur nor his or her employer has a pecuniary interest in the communications
C	When the total money involved does not exceed $25
D	When the control operator is employed by the FCC or another government agency

8. - E2A07

Which of the following types of signals can be relayed through a linear transponder?

Select	Answer
A	PSK and packet
B	FM and CW
C	SSB and SSTV
D	All these choices are correct

9. - E2B06

What is vestigial sideband modulation?

Select	Answer
A	Amplitude modulation in which one complete sideband and a portion of the other are transmitted
B	A type of modulation in which one sideband is inverted
C	Narrow-band FM modulation achieved by filtering one sideband from the audio before frequency modulating the carrier
D	Spread spectrum modulation achieved by applying FM modulation following single sideband amplitude modulation

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

11. - E2D09

What type of modulation is used for JT65 contacts?

Select	Answer
A	PSK
B	RTTY
C	Multi-tone AFSK
D	IEEE 802.11

12. - E2E09

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

Select	Answer
A	MT63
B	RTTY
C	PSK31
D	PACTOR

13. - E3A04

What do Hepburn maps predict?

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

14. - E3B09

At what time of year is sporadic E propagation most likely to occur?

Select	Answer
A	Around the equinoxes, especially the fall equinox
B	Around the solstices, especially the summer solstice
C	Around the solstices, especially the winter solstice
D	Around the equinoxes, especially the spring equinox

15. - E3C10

What does the 304A solar parameter measure?

Select	Answer
A	The ratio of x-ray flux to radio flux, correlated to sunspot number
B	The solar emission at 304 GHz, correlated to x-ray flare levels
C	The solar wind velocity at 304 degrees from the solar equator, correlated to solar activity
D	UV emissions at 304 angstroms, correlated to the solar flux index

16. - E4A09

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

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

17. - E4B01

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

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

18. - E4C09

Which of the following choices is a good reason for selecting a high frequency for the design of the IF in a superheterodyne HF or VHF communications receiver?

Select	Answer
A	Easier for front-end circuitry to eliminate image responses
B	Improved receiver noise figure
C	Reduced drift
D	Fewer components in the receiver

19. - E4D05

What transmitter frequencies would cause an intermodulation-product signal in a receiver tuned to 146.70 MHz when a nearby station transmits on 146.52 MHz?

Select	Answer
A	146.88 MHz and 146.34 MHz
B	146.10 MHz and 147.30 MHz
C	146.34 MHz and 146.61 MHz
D	173.35 MHz and 139.40 MHz

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

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	47.3 kHz
B	315.6 Hz
C	23.67 kHz
D	157.8 Hz

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

23. - E5C01

Which of the following represents capacitive reactance in rectangular notation?

Select	Answer
A	Delta
B	-jX
C	Omega
D	+jX

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. - E6A04

What is the name given to an impurity atom that adds holes to a semiconductor crystal structure?

Select	Answer
A	Acceptor impurity
B	N-type impurity
C	Donor impurity
D	Insulator impurity

26. - E6B04

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

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

27. - E6C11

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

Select	Answer
A	4
B	5
C	2
D	6

28. - E6D02

What is the equivalent circuit of a quartz crystal?

Select	Answer
A	Motional inductance and loss resistance in series, paralleled with motional capacitance and a capacitor representing electrode and stray capacitance
B	Motional capacitance, motional inductance, loss resistance, and a capacitor representing electrode and stray capacitance all in series
C	Motional capacitance, motional inductance, and loss resistance in series, all in parallel with a shunt capacitor representing electrode and stray capacitance
D	Motional capacitance, motional inductance, loss resistance, and a capacitor representing electrode and stray capacitance all in parallel

29. - E6E01

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

Select	Answer
A	Lower junction voltage drop
B	Lower transconductance
C	Higher electron mobility
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	A frequency modulated helium-neon laser
C	An LED and a phototransistor
D	An amplitude modulated helium-neon laser

31. - E7A02

What is the function of a decade counter?

Select	Answer
A	It produces 10 output pulses for every input pulse
B	It decodes a binary number for display on a seven-segment LED display
C	It decodes a decimal number for display on a seven-segment LED display
D	It produces one output pulse for every 10 input pulses

32. - E7B02

What is a Class D amplifier?

Select	Answer
A	An amplifier that uses drift-mode FETs for high efficiency
B	A low power amplifier that uses a differential amplifier for improved linearity
C	A type of amplifier that uses switching technology to achieve high efficiency
D	A frequency doubling amplifier

33. - E7C03

What advantage does a series-L Pi-L-network have over a series-L Pi-network for impedance matching between the final amplifier of a vacuum-tube transmitter and an antenna?

Select	Answer
A	Greater harmonic suppression
B	Greater transformation range
C	Does not require a capacitor
D	Higher efficiency

34. - E7D13

What is the equation for calculating power dissipated by a series linear voltage regulator?

Select	Answer
A	Output voltage multiplied by output current
B	Voltage difference from input to output multiplied by output current
C	Input voltage divided by output current
D	Input voltage multiplied by input current

35. - E7E10

How does a diode envelope detector function?

Select	Answer
A	By breakdown of the Zener voltage
B	By sensing the change of reactance in the diode with respect to frequency
C	By rectification and filtering of RF signals
D	By mixing signals with noise in the transition region of the diode

36. - E7F03

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

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

37. - E7G06

What is the gain-bandwidth of an operational amplifier?

Select	Answer
A	The frequency at which the open-loop gain of the amplifier equals one
B	The gain of the amplifier at a filter's cutoff frequency
C	The maximum frequency for a filter circuit using that type of amplifier
D	The frequency at which the amplifier's offset voltage is zero

38. - E7H11

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

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

39. - E8A07

What determines the PEP-to-average power ratio of a single-sideband phone signal?

Select	Answer
A	The degree of carrier suppression
B	Speech characteristics
C	The frequency of the modulating signal
D	Amplifier gain

40. - E8B11

What is digital time division multiplexing?

Select	Answer
A	Two or more data streams are assigned to discrete sub-carriers on an FM transmitter
B	Two or more signals are arranged to share discrete time slots of a data transmission
C	Two or more data streams share the same channel by transmitting time of transmission as the sub-carrier
D	Two or more signals are quadrature modulated to increase bandwidth efficiency

41. - E8C08

How does ARQ accomplish error correction?

Select	Answer
A	If errors are detected, redundant data is substituted
B	Special binary codes provide automatic correction
C	Special polynomial codes provide automatic correction
D	If errors are detected, a retransmission is requested

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	If interference is detected by the receiver it will signal the transmitter to change frequencies
C	The receiver is always equipped with a digital blanker
D	The high power used by a spread spectrum transmitter keeps its signal from being easily overpowered

43. - E9A10

Which of the following improves the efficiency of a ground-mounted quarter-wave vertical antenna?

Select	Answer
A	Shortening the radiating element
B	Installing a radial system
C	All these choices are correct
D	Isolating the coax shield from ground

44. - E9B06

What is the elevation angle of peak response in the antenna radiation pattern shown in Figure E9-2?

Select	Answer
A	25 degrees
B	75 degrees
C	45 degrees
D	7.5 degrees

45. - E9C07

What is the approximate feed point impedance at the center of a two-wire folded dipole antenna?

Select	Answer
A	72 ohms
B	50 ohms
C	450 ohms
D	300 ohms

46. - E9D03

Where should a high Q loading coil be placed to minimize losses in a shortened vertical antenna?

Select	Answer
A	As low as possible on the vertical radiator
B	Near the center of the vertical radiator
C	At a voltage node
D	As close to the transmitter as possible

47. - E9E07

What parameter describes the interactions at the load end of a mismatched transmission line?

Select	Answer
A	Reflection coefficient
B	Dielectric constant
C	Velocity factor
D	Characteristic impedance

48. - E9F01

What is the velocity factor of a transmission line?

Select	Answer
A	The velocity of the wave in the transmission line divided by the velocity of light in a vacuum
B	The index of shielding for coaxial cable
C	The velocity of the wave in the transmission line multiplied by the velocity of light in a vacuum
D	The ratio of the characteristic impedance of the line to the terminating impedance

49. - E9G10

What do the arcs on a Smith chart represent?

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

50. - E9H04

What is an advantage of placing a grounded electrostatic shield around a small loop direction-finding antenna?

Select	Answer
A	It increases signal strength by providing a better match to the feed line
B	It eliminates unbalanced capacitive coupling to the surroundings, improving the nulls
C	It adds capacitive loading, increasing the bandwidth of the antenna
D	It eliminates tracking errors caused by strong out-of-band signals

Figure E6-3

Figure E9-2