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

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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	Uranium Hexafluoride
B	Beryllium Oxide
C	Mica
D	Zinc oxide

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

3. - E1B09

Which amateur stations may be operated under RACES rules?

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

4. - E1C02

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

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

5. - E1D09

Which UHF amateur bands have frequencies authorized for space stations?

Select	Answer
A	70 cm and 33 cm
B	70 cm and 13 cm
C	70 cm only
D	33 cm and 13 cm

6. - E1E07

What should a VE do if a candidate fails to comply with the examiner's instructions during an amateur operator license examination?

Select	Answer
A	Allow the candidate to complete the examination, but invalidate the results
B	Immediately terminate the candidate's examination
C	Warn the candidate that continued failure to comply will result in termination of the examination
D	Immediately terminate everyone's examination and close the session

7. - E1F11

Which of the following best describes one of the standards that must be met by an external RF power amplifier if it is to qualify for a grant of FCC certification?

Select	Answer
A	It must exhibit a gain of 0 dB or less over its full output range
B	It must be capable of external RF switching between its input and output networks
C	It must produce full legal output when driven by not more than 5 watts of mean RF input power
D	It must satisfy the FCC's spurious emission standards when operated at the lesser of 1500 watts or its full output power

8. - E2A12

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

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

9. - E2B05

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

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

10. - E2C09

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

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

11. - E2D10

How can an APRS station be used to help support a public service communications activity?

Select	Answer
A	APRS stations with General Personnel Scanners can automatically relay the participant numbers and time as they pass the check points
B	An APRS station with an emergency medical technician can automatically transmit medical data to the nearest hospital
C	An APRS station with a Global Positioning System unit can automatically transmit information to show a mobile station's position during the event
D	All these choices are correct

12. - E2E02

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

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

13. - E3A02

What characterizes libration fading of an EME signal?

Select	Answer
A	A fluttery irregular fading
B	The returning echo is several hertz lower in frequency than the transmitted signal
C	A slow change in the pitch of the CW signal
D	A gradual loss of signal as the sun rises

14. - E3B05

Which amateur bands typically support long-path propagation?

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

15. - E3C03

Which of the following signal paths is most likely to experience high levels of absorption when the A index or K index is elevated?

Select	Answer
A	Sporadic E
B	NVIS
C	Transequatorial
D	Polar

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	Never use a DC-coupled probe to measure an AC circuit
C	Never use a high-impedance probe to measure a low-impedance circuit
D	All these choices are correct

17. - E4B04

Which S parameter represents input port return loss or reflection coefficient (equivalent to VSWR)?

Select	Answer
A	S12
B	S21
C	S11
D	S22

18. - E4C03

What is the term for the suppression in an FM receiver of one signal by another stronger signal on the same frequency?

Select	Answer
A	Capture effect
B	Desensitization
C	Cross-modulation interference
D	Frequency discrimination

19. - E4D03

How can intermodulation interference between two repeaters occur?

Select	Answer
A	When the signals from the transmitters are reflected in phase from airplanes passing overhead
B	When the signals from the transmitters are reflected out of phase from airplanes passing overhead
C	When the repeaters are in close proximity and the signals cause feedback in the final amplifier of one or both transmitters
D	When the repeaters are in close proximity and the signals mix in the final amplifier of one or both transmitters

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

21. - E5A14

What is the resonant frequency of an RLC circuit if R is 22 ohms, L is 50 microhenries and C is 40 picofarads?

Select	Answer
A	22.36 MHz
B	44.72 MHz
C	1.78 MHz
D	3.56 MHz

22. - E5B04

What is the time constant of a circuit having two 220-microfarad capacitors and two 1-megohm resistors, all in parallel?

Select	Answer
A	55 seconds
B	220 seconds
C	110 seconds
D	440 seconds

23. - E5C03

Which of the following represents an inductive reactance in polar coordinates?

Select	Answer
A	A positive magnitude
B	A negative magnitude
C	A negative phase angle
D	A positive phase angle

24. - E5D03

What is microstrip?

Select	Answer
A	Miniature coax used for low power applications
B	Lightweight transmission line made of common zip cord
C	Precision printed circuit conductors above a ground plane that provide constant impedance interconnects at microwave frequencies
D	Short lengths of coax mounted on printed circuit boards to minimize time delay between microwave circuits

25. - E6A02

Which of the following semiconductor materials contains excess free electrons?

Select	Answer
A	Insulated gate
B	P-type
C	Bipolar
D	N-type

26. - E6B10

In Figure E6-2, what is the schematic symbol for a light-emitting diode?

Select	Answer
A	5
B	6
C	7
D	1

27. - E6C08

In Figure E6-3, what is the schematic symbol for a NAND gate?

Select	Answer
A	2
B	1
C	3
D	4

28. - E6D04

Which materials are commonly used as a core in an inductor?

Select	Answer
A	Cobalt and aluminum
B	Ferrite and brass
C	Polystyrene and polyethylene
D	Teflon and Delrin

29. - E6E10

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

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

30. - E6F06

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

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

31. - E7A06

What is a characteristic of a monostable multivibrator?

Select	Answer
A	It stores one bit of data in either a 0 or 1 state
B	It maintains a constant output voltage, regardless of variations in the input voltage
C	It switches momentarily to the opposite binary state and then returns to its original state after a set time
D	It produces a continuous square wave oscillating between 1 and 0

32. - E7B03

Which of the following components form the output of a class D amplifier circuit?

Select	Answer
A	A high-pass filter to compensate for low gain at low frequencies
B	A temperature compensating load resistor to improve linearity
C	A low-pass filter to remove switching signal components
D	A matched load resistor to prevent damage by switching transients

33. - E7C09

What is a crystal lattice filter?

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

34. - E7D13

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

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

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 PM signals by using an electrically variable resistance
D	To produce AM signals by using an electrically variable resistance

36. - E7F04

What is a common method of generating an SSB signal using digital signal processing?

Select	Answer
A	A frequency synthesizer removes the unwanted sidebands
B	Varying quartz crystal characteristics emulated in digital form
C	Signals are combined in quadrature phase relationship
D	Mixing products are converted to voltages and subtracted by adder circuits

37. - E7G04

What is meant by the "op-amp input offset voltage"?

Select	Answer
A	The differential input voltage needed to bring the open loop output voltage to zero
B	The output voltage of the op-amp minus its input voltage
C	The potential between the amplifier input terminals of the op-amp in an open loop condition
D	The difference between the output voltage of the op-amp and the input voltage required in the immediately following stage

38. - E7H06

Which of the following oscillator circuits are commonly used in VFOs?

Select	Answer
A	Pierce and Zener
B	Armstrong and deForest
C	Negative feedback and balanced feedback
D	Colpitts and Hartley

39. - E8A10

What is the purpose of a low-pass filter used in conjunction with a digital-to-analog converter?

Select	Answer
A	Improve accuracy by removing out-of-sequence codes from the input
B	Remove harmonics from the output caused by the discrete analog levels generated
C	Lower the input bandwidth to increase the effective resolution
D	All these choices are correct

40. - E8B11

What is digital time division multiplexing?

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

41. - E8C12

What factors affect the bandwidth of a transmitted CW signal?

Select	Answer
A	Keying speed and shape factor (rise and fall time)
B	Modulation index and output power
C	IF bandwidth and Q
D	All these choices are correct

42. - E8D11

What is one advantage of using ASCII code for data communications?

Select	Answer
A	It is possible to transmit both upper and lower case text
B	It includes built-in error correction features
C	It uses one character as a shift code to send numeric and special characters
D	It contains fewer information bits per character than any other code

43. - E9A11

Which of the following factors determines ground losses for a ground-mounted vertical antenna operating in the 3 MHz to 30 MHz range?

Select	Answer
A	Take-off angle
B	The standing wave ratio
C	Distance from the transmitter
D	Soil conductivity

44. - E9B05

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

Select	Answer
A	Azimuth
B	Polarization
C	Elevation
D	Radiation resistance

45. - E9C10

Which of the following describes a Zepp antenna?

Select	Answer
A	An end-fed dipole antenna
B	A vertical array capable of quickly changing the direction of maximum radiation by changing phasing lines
C	A dipole constructed from zip cord
D	An omni-directional antenna commonly used for satellite communications

46. - E9D01

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

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

47. - E9E01

What system matches a higher-impedance transmission line to a lower-impedance antenna by connecting the line to the driven element in two places spaced a fraction of a wavelength each side of element center?

Select	Answer
A	The omega matching system
B	The stub matching system
C	The delta matching system
D	The gamma matching system

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. - E9G06

On the Smith chart shown in Figure E9-3, what is the name for the large outer circle on which the reactance arcs terminate?

Select	Answer
A	Polar axis
B	Impedance axis
C	Reactance axis
D	Prime axis

50. - E9H05

What is the main drawback of a small wire-loop antenna for direction finding?

Select	Answer
A	All these choices are correct
B	It has no clearly defined null
C	It has a bidirectional pattern
D	It is practical for use only on VHF and higher bands

Figure E6-2

Figure E6-3

Figure E9-2

Figure E9-3