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. - E0A09

Which insulating material commonly used as a thermal conductor for some types of electronic devices is extremely toxic if broken or crushed and the particles are accidentally inhaled?

Select	Answer
A	Mica
B	Beryllium Oxide
C	Zinc oxide
D	Uranium Hexafluoride

2. - E1A13

Who must be in physical control of the station apparatus of an amateur station aboard any vessel or craft that is documented or registered in the United States?

Select	Answer
A	Any person named in an amateur station license grant or a person holding an unrestricted Radiotelephone Operator Permit
B	Only a person named in an amateur station license grant
C	Only a person with an FCC Marine Radio license grant
D	Any person holding an FCC issued amateur license or who is authorized for alien reciprocal operation

3. - E1B01

Which of the following constitutes a spurious emission?

Select	Answer
A	An emission outside the signal's necessary bandwidth that can be reduced or eliminated without affecting the information transmitted
B	A signal transmitted to prevent its detection by any station other than the intended recipient
C	An amateur station transmission made without the proper call sign identification
D	Any transmitted signal that unintentionally interferes with another licensed radio station

4. - E1C08

What is the maximum permissible duration of a remotely controlled station's transmissions if its control link malfunctions?

Select	Answer
A	5 minutes
B	10 minutes
C	3 minutes
D	30 seconds

5. - E1D05

What must be posted at the station location of a station being operated by telecommand on or within 50 km of the earth's surface?

Select	Answer
A	A label with the name, address, and telephone number of the control operator
B	A photocopy of the station license
C	A label with the name, address, and telephone number of the station licensee
D	All these choices are correct

6. - E1E04

Which of the following best describes the Volunteer Examiner accreditation process?

Select	Answer
A	Each General, Advanced and Amateur Extra Class operator is automatically accredited as a VE when the license is granted
B	The amateur operator applying must pass a VE examination administered by the FCC Enforcement Bureau
C	The procedure by which a VEC confirms that the VE applicant meets FCC requirements to serve as an examiner
D	The prospective VE obtains accreditation from the FCC

7. - E1F04

Which of the following geographic descriptions approximately describes "Line A"?

Select	Answer
A	A line roughly parallel to and east of the U.S. Pacific coastline
B	A line roughly parallel to and south of the border between the U.S. and Canada
C	A line roughly parallel to and west of the U.S. Atlantic coastline
D	A line roughly parallel to and north of the border between the U.S. and Mexico

8. - E2A13

Which of the following techniques is normally used by low Earth orbiting digital satellites to relay messages around the world?

Select	Answer
A	Node hopping
B	Digipeating
C	Store-and-forward
D	Multi-satellite relaying

9. - E2B05

Which of the following describes the use of vestigial sideband in analog fast-scan TV transmissions?

Select	Answer
A	The vestigial sideband carries the audio information
B	The vestigial sideband contains chroma information
C	Vestigial sideband provides high frequency emphasis to sharpen the picture
D	Vestigial sideband reduces bandwidth while allowing for simple video detector circuitry

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

11. - E2D07

What digital protocol is used by APRS?

Select	Answer
A	AMTOR
B	PACTOR
C	AX.25
D	802.11

12. - E2E02

What do the letters FEC mean as they relate to digital operation?

Select	Answer
A	First Error Correction
B	Fatal Error Correction
C	Final Error Correction
D	Forward Error Correction

13. - E3A04

What do Hepburn maps predict?

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

14. - E3B07

What happens to linearly polarized radio waves that split into ordinary and extraordinary waves in the ionosphere?

Select	Answer
A	They are bent toward the magnetic poles
B	They become depolarized
C	They become phase locked
D	They become elliptically polarized

15. - E3C05

What orientation of Bz (B sub z) increases the likelihood that incoming particles from the sun will cause disturbed conditions?

Select	Answer
A	Eastward
B	Westward
C	Northward
D	Southward

16. - E4A04

How is the compensation of an oscilloscope probe typically adjusted?

Select	Answer
A	A square wave is displayed and the probe is adjusted until the horizontal portions of the displayed wave are as nearly flat as possible
B	A frequency standard is displayed and the probe is adjusted until the deflection time is accurate
C	A high frequency sine wave is displayed and the probe is adjusted for maximum amplitude
D	A DC voltage standard is displayed and the probe is adjusted until the displayed voltage is accurate

17. - E4B10

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

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

18. - E4C10

What is an advantage of having a variety of receiver IF bandwidths from which to select?

Select	Answer
A	The noise figure of the RF amplifier can be adjusted to match the modulation type, thus increasing receiver sensitivity
B	Multiple frequencies can be received simultaneously if desired
C	Receiver power consumption can be reduced when wider bandwidth is not required
D	Receive bandwidth can be set to match the modulation bandwidth, maximizing signal-to-noise ratio and minimizing interference

19. - E4D08

What causes intermodulation in an electronic circuit?

Select	Answer
A	Lack of neutralization
B	Nonlinear circuits or devices
C	Too little gain
D	Positive feedback

20. - E4E03

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

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

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. - E5B12

What is admittance?

Select	Answer
A	The turns ratio of a transformer
B	The inverse of Q factor
C	The term for the gain of a field effect transistor
D	The inverse of impedance

23. - E5C11

Which point in Figure E5-1 best represents the impedance of a series circuit consisting of a 300-ohm resistor and an 18-microhenry inductor at 3.505 MHz?

Select	Answer
A	Point 1
B	Point 8
C	Point 7
D	Point 3

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

25. - E6A07

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

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

26. - E6B08

Which of the following is a Schottky barrier diode?

Select	Answer
A	Electrolytic rectifier
B	PIN junction
C	Metal-semiconductor junction
D	Thermionic emission diode

27. - E6C01

What is the function of hysteresis in a comparator?

Select	Answer
A	To cause the output to change states continually
B	To prevent input noise from causing unstable output signals
C	To increase the sensitivity
D	To allow the comparator to be used with AC input signals

28. - E6D05

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

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

29. - E6E10

What advantage does surface-mount technology offer at RF compared to using through-hole components?

Select	Answer
A	Components have less parasitic inductance and capacitance
B	Shorter circuit-board traces
C	Smaller circuit area
D	All these choices are correct

30. - E6F11

What is the approximate open-circuit voltage produced by a fully illuminated silicon photovoltaic cell?

Select	Answer
A	0.1 V
B	12 V
C	1.5 V
D	0.5 V

31. - E7A03

Which of the following can divide the frequency of a pulse train by 2?

Select	Answer
A	An OR gate
B	A flip-flop
C	A multiplexer
D	An XOR gate

32. - E7B08

How can an RF power amplifier be neutralized?

Select	Answer
A	By feeding an in-phase component of the output back to the input
B	By feeding a 180-degree out-of-phase portion of the output back to the input
C	By reducing the driving power
D	By increasing the driving power

33. - E7C12

What is one advantage of a Pi-matching network over an L-matching network consisting of a single inductor and a single capacitor?

Select	Answer
A	L-networks cannot perform impedance transformation
B	Pi-networks provide balanced input and output
C	The Q of Pi-networks can be controlled
D	Pi-networks are more stable

34. - E7D04

Which of the following types of linear voltage regulator usually make the most efficient use of the primary power source?

Select	Answer
A	A series current source
B	A shunt current source
C	A series regulator
D	A shunt regulator

35. - E7E08

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

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

36. - E7F12

Which of the following is an advantage of a Finite Impulse Response (FIR) filter vs an Infinite Impulse Response (IIR) digital filter?

Select	Answer
A	All these choices are correct
B	FIR filters are easier to implement for a given set of passband rolloff requirements
C	FIR filters can respond faster to impulses
D	FIR filters can delay all frequency components of the signal by the same amount

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	0.03
C	1
D	76

38. - E7H03

How is positive feedback supplied in a Hartley oscillator?

Select	Answer
A	Through a tapped coil
B	Through a capacitive divider
C	Through link coupling
D	Through a neutralizing capacitor

39. - E8A08

Why would a direct or flash conversion analog-to-digital converter be useful for a software defined radio?

Select	Answer
A	Very low power consumption decreases frequency drift
B	Immunity to out-of-sequence coding reduces spurious responses
C	All these choices are correct
D	Very high speed allows digitizing high frequencies

40. - E8B08

What describes Orthogonal Frequency Division Multiplexing?

Select	Answer
A	A bandwidth compression technique using Fourier transforms
B	A frequency modulation technique that uses non-harmonically related frequencies
C	A digital modulation technique using subcarriers at frequencies chosen to avoid intersymbol interference
D	A digital mode for narrow-band, slow-speed transmissions

41. - E8C06

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

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

42. - E8D08

What parameter evaluates distortion of an AFSK signal caused by excessive input audio levels?

Select	Answer
A	Baud rate
B	Signal-to-noise ratio
C	Repeat Request Rate (RRR)
D	Intermodulation Distortion (IMD)

43. - E9A12

How much gain does an antenna have compared to a 1/2-wavelength dipole when it has 6 dB gain over an isotropic antenna?

Select	Answer
A	2.79 dB
B	6.0 dB
C	3.85 dB
D	8.15 dB

44. - E9B03

In the antenna radiation pattern shown in Figure E9-1, what is the front-to-side ratio?

Select	Answer
A	14 dB
B	12 dB
C	24 dB
D	18 dB

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

46. - E9D01

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

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

47. - E9E11

What is the primary purpose of phasing lines when used with an antenna having multiple driven elements?

Select	Answer
A	It prevents reflected power from traveling back down the feed line and causing harmonic radiation from the transmitter
B	It allows single-band antennas to operate on other bands
C	It creates a low-angle radiation pattern
D	It ensures that each driven element operates in concert with the others to create the desired antenna pattern

48. - E9F03

Why is the physical length of a coaxial cable transmission line shorter than its electrical length?

Select	Answer
A	Electrical signals move more slowly in a coaxial cable than in air
B	The characteristic impedance is higher in a parallel feed line
C	Skin effect is less pronounced in the coaxial cable
D	The surge impedance is higher in a parallel feed line

49. - E9G09

What third family of circles is often added to a Smith chart during the process of solving problems?

Select	Answer
A	Antenna-length circles
B	Radiation-pattern circles
C	Coaxial-length circles
D	Standing wave ratio circles

50. - E9H10

How can the output voltage of a multiple-turn receiving loop antenna be increased?

Select	Answer
A	By winding adjacent turns in opposing directions
B	By increasing the number of turns and/or the area
C	By reducing the permeability of the loop shield
D	By utilizing high impedance wire for the coupling loop

Figure E5-1

Figure E7-3

Figure E9-1