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

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1. - E0A11

Which of the following injuries can result from using high-power UHF or microwave transmitters?

Select	Answer
A	Hearing loss caused by high voltage corona discharge
B	Localized heating of the body from RF exposure in excess of the MPE limits
C	Blood clotting from the intense magnetic field
D	Ingestion of ozone gas from the cooling system

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

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

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	Business-related messages for non-profit organizations
C	Messages intended for users of the maritime satellite service
D	All these choices are correct

5. - E1D03

What is a space telecommand station?

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

6. - E1E02

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

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

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. - E2A12

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

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

9. - E2B01

How many times per second is a new frame transmitted in a fast-scan (NTSC) television system?

Select	Answer
A	120
B	90
C	60
D	30

10. - E2C09

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

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

11. - E2D03

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

Select	Answer
A	JT65
B	Olivia
C	MSK144
D	PACTOR III

12. - E2E07

Which of the following is a possible reason that attempts to initiate contact with a digital station on a clear frequency are unsuccessful?

Select	Answer
A	Your transmit frequency is incorrect
B	All these choices are correct
C	Another station you are unable to hear is using the frequency
D	The protocol version you are using is not supported by the digital station

13. - E3A06

What might help to restore contact when DX signals become too weak to copy across an entire HF band a few hours after sunset?

Select	Answer
A	Switch to a lower frequency HF band
B	Wait 24 hours before attempting another communication on the band
C	Switch to a higher frequency HF band
D	Wait 90 minutes or so for the signal degradation to pass

14. - E3B03

What is the best time of day for transequatorial propagation?

Select	Answer
A	Late at night
B	Afternoon or early evening
C	Noon
D	Morning

15. - E3C06

By how much does the VHF/UHF radio horizon distance exceed the geometric horizon?

Select	Answer
A	By approximately 50 percent of the distance
B	By approximately four times the distance
C	By approximately twice the distance
D	By approximately 15 percent of the distance

16. - E4A02

Which of the following parameters does a spectrum analyzer display on the vertical and horizontal axes?

Select	Answer
A	SWR and time
B	RF amplitude and time
C	RF amplitude and frequency
D	SWR and frequency

17. - E4B05

What three test loads are used to calibrate an RF vector network analyzer?

Select	Answer
A	Short circuit, open circuit, and resonant circuit
B	50 ohms through 1/8 wavelength, 1/4 wavelength, and 1/2 wavelength of coaxial cable
C	50 ohms, 75 ohms, and 90 ohms
D	Short circuit, open circuit, and 50 ohms

18. - E4C01

What is an effect of excessive phase noise in a receiver's local oscillator?

Select	Answer
A	It can combine with strong signals on nearby frequencies to generate interference
B	It limits the receiver's ability to receive strong signals
C	It decreases receiver third-order intercept point
D	It can affect the receiver's frequency calibration

19. - E4D04

Which of the following may reduce or eliminate intermodulation interference in a repeater caused by another transmitter operating in close proximity?

Select	Answer
A	A properly terminated circulator at the output of the repeater's transmitter
B	Utilizing a Class D final amplifier
C	Utilizing a Class C final amplifier
D	A band-pass filter in the feed line between the transmitter and receiver

20. - E4E09

What undesirable effect can occur when using an IF noise blanker?

Select	Answer
A	The audio frequency bandwidth of the received signal might be compressed
B	Nearby signals may appear to be excessively wide even if they meet emission standards
C	Received audio in the speech range might have an echo effect
D	FM signals can no longer be demodulated

21. - E5A09

How is the Q of an RLC parallel resonant circuit calculated?

Select	Answer
A	Reactance of either the inductance or capacitance divided by the resistance
B	Reactance of the inductance multiplied by the reactance of the capacitance
C	Resistance divided by the reactance of either the inductance or capacitance
D	Reactance of either the inductance or capacitance multiplied by the resistance

22. - E5B08

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 100 ohms, R is 100 ohms, and XL is 75 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. - E5C02

How are impedances described in polar coordinates?

Select	Answer
A	By real and imaginary parts
B	By X and R values
C	By Y and G values
D	By phase angle and magnitude

24. - E5D10

How can the true power be determined in an AC circuit where the voltage and current are out of phase?

Select	Answer
A	By dividing the apparent power by the power factor
B	By multiplying the apparent power by the power factor
C	By multiplying the reactive power by the power factor
D	By dividing the reactive power by the power factor

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

26. - E6B03

What type of bias is required for an LED to emit light?

Select	Answer
A	Forward bias
B	Reverse bias
C	Inductive bias
D	Zero bias

27. - E6C10

In Figure E6-3, what is the schematic symbol for a NOR gate?

Select	Answer
A	2
B	1
C	4
D	3

28. - E6D09

What devices are commonly used as VHF and UHF parasitic suppressors at the input and output terminals of a transistor HF amplifier?

Select	Answer
A	Butterworth filters
B	Steel-core toroids
C	Electrolytic capacitors
D	Ferrite beads

29. - E6E02

Which of the following device packages is a through-hole type?

Select	Answer
A	DIP
B	SOT
C	Ball grid array
D	PLCC

30. - E6F01

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

Select	Answer
A	Holes
B	Electrons
C	Photons
D	Protons

31. - E7A10

What is a truth table?

Select	Answer
A	A diagram showing logic states when the digital device output is true
B	A list of inputs and corresponding outputs for a digital device
C	A table of logic symbols that indicate the logic states of an op-amp
D	A table of logic symbols that indicate the high logic states of an op-amp

32. - E7B15

What is one way to prevent thermal runaway in a bipolar transistor amplifier?

Select	Answer
A	Select transistors with high beta
B	Use a resistor in series with the emitter
C	Neutralization
D	All these choices are correct

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	The Q of Pi-networks can be controlled
C	Pi-networks are more stable
D	Pi-networks provide balanced input and output

34. - E7D14

What is the purpose of connecting equal-value resistors across power supply filter capacitors connected in series?

Select	Answer
A	Equalize the voltage across each capacitor
B	All these choices are correct
C	Provide a minimum load on the supply
D	Discharge the capacitors when voltage is removed

35. - E7E03

What is a frequency discriminator stage in a FM receiver?

Select	Answer
A	A circuit for detecting FM signals
B	An FM generator circuit
C	An automatic band-switching circuit
D	A circuit for filtering two closely adjacent signals

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	Signals are combined in quadrature phase relationship
C	Varying quartz crystal characteristics emulated in digital form
D	Mixing products are converted to voltages and subtracted by adder circuits

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	0.21
B	94
C	24
D	47

38. - E7H14

What is a phase-locked loop circuit?

Select	Answer
A	An electronic servo loop consisting of a phase detector, a low-pass filter, a voltage-controlled oscillator, and a stable reference oscillator
B	An electronic circuit consisting of a precision push-pull amplifier with a differential input
C	An electronic servo loop consisting of a ratio detector, reactance modulator, and voltage-controlled oscillator
D	An electronic circuit also known as a monostable multivibrator

39. - E8A07

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

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

40. - E8B01

What is the modulation index of an FM signal?

Select	Answer
A	The ratio of modulating signal amplitude to frequency deviation
B	The ratio of frequency deviation to modulating signal frequency
C	The type of modulation used by the transmitter
D	The bandwidth of the transmitted signal divided by the modulating signal frequency

41. - E8C12

What factors affect the bandwidth of a transmitted CW signal?

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

42. - E8D03

How does the spread spectrum technique of frequency hopping work?

Select	Answer
A	The frequency of the transmitted signal is changed very rapidly according to a pseudorandom sequence also used by the receiving station
B	A binary bit stream is used to shift the phase of an RF carrier very rapidly in a pseudorandom sequence
C	If interference is detected by the receiver it will signal the transmitter to wait until the frequency is clear
D	If interference is detected by the receiver it will signal the transmitter to change frequencies

43. - E9A13

What term describes station output, taking into account all gains and losses?

Select	Answer
A	Power factor
B	Effective radiated power
C	Apparent power
D	Half-power bandwidth

44. - E9B05

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

Select	Answer
A	Radiation resistance
B	Polarization
C	Azimuth
D	Elevation

45. - E9C05

Which of the following is a type of OCFD antenna?

Select	Answer
A	A folded dipole center-fed with 300-ohm transmission line
B	A dipole fed approximately 1/3 the way from one end with a 4:1 balun to provide multiband operation
C	A multiband dipole antenna using one-way circular polarization for frequency diversity
D	A remotely tunable dipole antenna using orthogonally controlled frequency diversity

46. - E9D07

What is an advantage of using top loading in a shortened HF vertical antenna?

Select	Answer
A	Lower Q
B	Improved radiation efficiency
C	Higher losses
D	Greater structural strength

47. - E9E05

How must an antenna's driven element be tuned to use a hairpin matching system?

Select	Answer
A	The driven element reactance must be capacitive
B	The driven element radiation resistance must be higher than the characteristic impedance of the transmission line
C	The driven element resonance must be lower than the operating frequency
D	The driven element reactance must be inductive

48. - E9F02

Which of the following has the biggest effect on the velocity factor of a transmission line?

Select	Answer
A	The line length
B	Dielectric materials used in the line
C	The center conductor resistivity
D	The termination impedance

49. - E9G08

What is the process of normalization with regard to a Smith chart?

Select	Answer
A	Reassigning prime center with regard to the reactance axis
B	Reassigning reactance values with regard to the resistance axis
C	Reassigning impedance values with regard to the prime center
D	Reassigning resistance values with regard to the reactance axis

50. - E9H06

What is the triangulation method of direction finding?

Select	Answer
A	The geometric angles of sky waves from the source are used to determine its position
B	A fixed receiving station plots three headings to the signal source
C	Antenna headings from several different receiving locations are used to locate the signal source
D	A fixed receiving station uses three different antennas to plot the location of the signal source

Figure E6-3

Figure E9-2