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	Beryllium Oxide
B	Uranium Hexafluoride
C	Zinc oxide
D	Mica

2. - E1A02

When using a transceiver that displays the carrier frequency of phone signals, which of the following displayed frequencies represents the lowest frequency at which a properly adjusted LSB emission will be totally within the band?

Select	Answer
A	300 Hz above the lower band edge
B	3 kHz above the lower band edge
C	1 kHz above the lower band edge
D	The exact lower band edge

3. - E1B12

What must the control operator of a repeater operating in the 70 cm band do if a radiolocation system experiences interference from that repeater?

Select	Answer
A	Cease operation or make changes to the repeater to mitigate the interference
B	Reduce the repeater antenna HAAT (Height Above Average Terrain)
C	All these choices are correct
D	File an FAA NOTAM (Notice to Airmen) with the repeater system's ERP, call sign, and six-character grid locator

4. - E1C07

At what level below a signal's mean power level is its bandwidth determined according to FCC rules?

Select	Answer
A	23 dB
B	3 dB
C	26 dB
D	6 dB

5. - E1D08

Which VHF amateur bands have frequencies authorized for space stations?

Select	Answer
A	2 meters
B	6 meters, 2 meters, and 1.25 meters
C	6 meters and 2 meters
D	2 meters and 1.25 meters

6. - E1E04

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

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

7. - E1F10

Who may be the control operator of an auxiliary station?

Select	Answer
A	Only General, Advanced or Amateur Extra Class operators
B	Only Technician, General, Advanced or Amateur Extra Class operators
C	Only Amateur Extra Class operators
D	Any licensed amateur operator

8. - E2A08

Why should effective radiated power to a satellite that uses a linear transponder be limited?

Select	Answer
A	To prevent the satellite from emitting out-of-band signals
B	To avoid reducing the downlink power to all other users
C	To avoid interfering with terrestrial QSOs
D	To prevent creating errors in the satellite telemetry

9. - E2B09

What hardware, other than a receiver with SSB capability and a suitable computer, is needed to decode SSTV using Digital Radio Mondiale (DRM)?

Select	Answer
A	A special front end limiter
B	A special IF converter
C	No other hardware is needed
D	A special notch filter to remove synchronization pulses

10. - E2C10

Why might a DX station state that they are listening on another frequency?

Select	Answer
A	All these choices are correct
B	To improve operating efficiency by reducing interference
C	Because the DX station may be transmitting on a frequency that is prohibited to some responding stations
D	To separate the calling stations from the DX station

11. - E2D08

What type of packet frame is used to transmit APRS beacon data?

Select	Answer
A	Acknowledgement
B	Disconnect
C	Connect
D	Unnumbered Information

12. - E2E09

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

Select	Answer
A	PACTOR
B	MT63
C	PSK31
D	RTTY

13. - E3A04

What do Hepburn maps predict?

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

14. - E3B09

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

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

15. - E3C09

How does the intensity of an X3 flare compare to that of an X2 flare?

Select	Answer
A	50 percent greater
B	Twice as great
C	10 percent greater
D	Four times as great

16. - E4A07

Which of the following is an advantage of using an antenna analyzer compared to an SWR bridge to measure antenna SWR?

Select	Answer
A	All these choices are correct
B	Antenna analyzers display a time-varying representation of the modulation envelope
C	Antenna analyzers automatically tune your antenna for resonance
D	Antenna analyzers do not need an external RF source

17. - E4B01

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

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

18. - E4C07

What does the MDS of a receiver represent?

Select	Answer
A	The minimum discernible signal
B	The meter display sensitivity
C	The maximum detectable spectrum
D	The multiplex distortion stability

19. - E4D06

What is the term for spurious signals generated by the combination of two or more signals in a non-linear device or circuit?

Select	Answer
A	Adjacent channel interference
B	Amplifier desensitization
C	Neutralization
D	Intermodulation

20. - E4E02

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

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

21. - E5A12

What is the half-power bandwidth of a resonant circuit that has a resonant frequency of 3.7 MHz and a Q of 118?

Select	Answer
A	31.4 kHz
B	15.7 kHz
C	436.6 kHz
D	218.3 kHz

22. - E5B12

What is admittance?

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

23. - E5C04

What coordinate system is often used to display the resistive, inductive, and/or capacitive reactance components of impedance?

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

24. - E5D05

What is the power factor of an RL circuit having a 30-degree phase angle between the voltage and the current?

Select	Answer
A	0.866
B	0.5
C	1.73
D	0.577

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	An FET has lower input impedance
C	An FET has higher input impedance
D	They are both high impedance

26. - E6B07

What is the failure mechanism when a junction diode fails due to excessive current?

Select	Answer
A	Excessive junction temperature
B	Charge carrier depletion
C	Insufficient forward voltage
D	Excessive inverse voltage

27. - E6C02

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

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

28. - E6D08

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

Select	Answer
A	Powdered-iron cores generally require fewer turns to produce a given inductance
B	Powdered-iron cores generally have greater initial permeability
C	Powdered-iron cores generally maintain their characteristics at higher currents
D	Powdered-iron cores use smaller diameter wire for the same inductance

29. - E6E08

How is power supplied to the most common type of MMIC?

Select	Answer
A	Directly to the bias voltage (VCC IN) lead
B	Through a capacitor and RF choke connected to the amplifier input lead
C	Through a resistor and/or RF choke connected to the amplifier output lead
D	MMICs require no operating bias

30. - E6F01

What absorbs the energy from light falling on a photovoltaic cell?

Select	Answer
A	Photons
B	Electrons
C	Protons
D	Holes

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

32. - E7B06

Which of the following amplifier types reduces even-order harmonics?

Select	Answer
A	Push-push
B	Push-pull
C	Class C
D	Class AB

33. - E7C05

Which filter type is described as having ripple in the passband and a sharp cutoff?

Select	Answer
A	A Chebyshev filter
B	A Butterworth filter
C	A passive op-amp filter
D	An active LC filter

34. - E7D10

What is the primary reason that a high-frequency switching type high-voltage power supply can be both less expensive and lighter in weight than a conventional power supply?

Select	Answer
A	It uses a diode bridge rectifier for increased output
B	The high frequency inverter design uses much smaller transformers and filter components for an equivalent power output
C	The inverter design does not require any output filtering
D	It uses a large power factor compensation capacitor to recover power from the unused portion of the AC cycle

35. - E7E02

What is the function of a reactance modulator?

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

36. - E7F02

What kind of digital signal processing audio filter is used to remove unwanted noise from a received SSB signal?

Select	Answer
A	An adaptive filter
B	A Hilbert-transform filter
C	A phase-inverting filter
D	A crystal-lattice filter

37. - E7G04

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

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

38. - E7H08

Which of the following components can be used to reduce thermal drift in crystal oscillators?

Select	Answer
A	NP0 capacitors
B	Non-inductive resistors
C	Wirewound resistors
D	Toroidal inductors

39. - E8A02

Which of the following is a type of analog-to-digital conversion?

Select	Answer
A	Level shifting
B	Successive approximation
C	Harmonic regeneration
D	Phase reversal

40. - E8B11

What is digital time division multiplexing?

Select	Answer
A	Two or more signals are arranged to share discrete time slots of a data transmission
B	Two or more data streams share the same channel by transmitting time of transmission as the sub-carrier
C	Two or more data streams are assigned to discrete sub-carriers on an FM transmitter
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 polynomial codes provide automatic correction
C	If errors are detected, a retransmission is requested
D	Special binary codes provide automatic correction

42. - E8D02

What spread spectrum communications technique uses a high-speed binary bit stream to shift the phase of an RF carrier?

Select	Answer
A	Frequency hopping
B	Phase compandored spread spectrum
C	Binary phase-shift keying
D	Direct sequence

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

44. - E9B03

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

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

45. - E9C08

What is a folded dipole antenna?

Select	Answer
A	A dipole one-quarter wavelength long
B	A half-wave dipole with an additional parallel wire connecting its two ends
C	A dipole configured to provide forward gain
D	A type of ground-plane antenna

46. - E9D01

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

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

47. - E9E02

What is the name of an antenna matching system that matches an unbalanced feed line to an antenna by feeding the driven element both at the center of the element and at a fraction of a wavelength to one side of center?

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

48. - E9F04

What impedance does a 1/2-wavelength transmission line present to a generator when the line is shorted at the far end?

Select	Answer
A	Very high impedance
B	The same as the characteristic impedance of the line
C	Very low impedance
D	The same as the output impedance of the generator

49. - E9G05

Which of the following is a common use for a Smith chart?

Select	Answer
A	Determine the length and position of an impedance matching stub
B	Determine the impedance of a transmission line, given the physical dimensions
C	Determine the gain of an antenna given the physical and electrical parameters
D	Determine the loss/100 feet of a transmission line, given the velocity factor and conductor materials

50. - E9H08

What is the function of a sense antenna?

Select	Answer
A	It modifies the pattern of a DF antenna array to provide a null in one direction
B	It provides diversity reception that cancels multipath signals
C	It allows DF antennas to receive signals at different vertical angles
D	It increases the sensitivity of a DF antenna array

Figure E9-1