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

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1. - E0A03

Over what range of frequencies are the FCC human body RF exposure limits most restrictive?

Select	Answer
A	300 to 3000 MHz
B	3 to 30 MHz
C	30 to 300 MHz
D	300 kHz to 3 MHz

2. - E1A09

What action or actions should you take if your digital message forwarding station inadvertently forwards a communication that violates FCC rules?

Select	Answer
A	Discontinue forwarding the communication as soon as you become aware of it
B	Notify the originating station that the communication does not comply with FCC rules
C	Notify the nearest FCC Field Engineers office
D	All these choices are correct

3. - E1B01

Which of the following constitutes a spurious emission?

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

4. - E1C10

What is the permitted mean power of any spurious emission relative to the mean power of the fundamental emission from a station transmitter or external RF amplifier installed after January 1, 2003 and transmitting on a frequency below 30 MHz?

Select	Answer
A	At least 63 dB below
B	At least 53 dB below
C	At least 43 dB below
D	At least 73 dB below

5. - E1D02

Which of the following may transmit special codes intended to obscure the meaning of messages?

Select	Answer
A	Telecommand signals from a space telecommand station
B	Binary control characters
C	Data containing personal information
D	Auxiliary relay links carrying repeater audio

6. - E1E05

What is the minimum passing score on all amateur operator license examinations?

Select	Answer
A	Minimum passing score of 80%
B	Minimum passing score of 77%
C	Minimum passing score of 70%
D	Minimum passing score of 74%

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

8. - E2A12

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

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

9. - E2B12

What signals SSTV receiving software to begin a new picture line?

Select	Answer
A	Specific tone frequencies
B	Elapsed time
C	Specific tone amplitudes
D	A two-tone signal

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

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	All these choices are correct
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	An APRS station with an emergency medical technician can automatically transmit medical data to the nearest hospital

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. - E3A07

Atmospheric ducts capable of propagating microwave signals often form over what geographic feature?

Select	Answer
A	Forests
B	Mountain ranges
C	Urban areas
D	Bodies of water

14. - E3B12

What is the primary characteristic of chordal hop propagation?

Select	Answer
A	Successive ionospheric refractions without an intermediate reflection from the ground
B	Signals reflected back toward the transmitting station
C	Propagation across the geomagnetic equator
D	Propagation away from the great circle bearing between stations

15. - E3C09

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

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

16. - E4A02

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

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

17. - E4B07

What do the subscripts of S parameters represent?

Select	Answer
A	Frequency order of the measurements
B	Relative quality of the data
C	The port or ports at which measurements are made
D	The relative time between measurements

18. - E4C05

What does a receiver noise floor of -174 dBm represent?

Select	Answer
A	The minimum detectable signal as a function of receive frequency
B	The galactic noise contribution to minimum detectable signal
C	The noise figure of a 1 Hz bandwidth receiver
D	The theoretical noise in a 1 Hz bandwidth at the input of a perfect receiver at room temperature

19. - E4D08

What causes intermodulation in an electronic circuit?

Select	Answer
A	Too little gain
B	Nonlinear circuits or devices
C	Lack of neutralization
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 appear across a wide bandwidth
B	Signals that have a sharply peaked frequency distribution
C	Signals that appear at one IF but not another
D	Signals that are constant at all IF levels

21. - E5A05

What is the result of increasing the Q of an impedance-matching circuit?

Select	Answer
A	Matching range is increased
B	Matching bandwidth is increased
C	It has no effect on impedance matching
D	Matching bandwidth is decreased

22. - E5B09

What is the relationship between the AC current through a capacitor and the voltage across a capacitor?

Select	Answer
A	Voltage and current are 180 degrees out of phase
B	Current leads voltage by 90 degrees
C	Voltage and current are in phase
D	Voltage leads current by 90 degrees

23. - E5C02

How are impedances described in polar coordinates?

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

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	1.73
B	0.5
C	0.577
D	0.866

25. - E6A06

What is the beta of a bipolar junction transistor?

Select	Answer
A	The change in collector current with respect to base current
B	The frequency at which the current gain is reduced to 0.707
C	The breakdown voltage of the base to collector junction
D	The switching speed

26. - E6B06

Which of the following is a common use of a Schottky diode?

Select	Answer
A	As a variable capacitance in an automatic frequency control circuit
B	As a rectifier in high current power supplies
C	As a VHF/UHF mixer or detector
D	As a constant voltage reference in a power supply

27. - E6C01

What is the function of hysteresis in a comparator?

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

28. - E6D06

What core material property determines the inductance of an inductor?

Select	Answer
A	Permeability
B	Resistance
C	Thermal impedance
D	Reactivity

29. - E6E09

Which of the following component package types would be most suitable for use at frequencies above the HF range?

Select	Answer
A	Surface mount
B	Radial lead
C	TO-220
D	Axial lead

30. - E6F10

What is the most common type of photovoltaic cell used for electrical power generation?

Select	Answer
A	Silicon
B	Cadmium Sulfide
C	Copper oxide
D	Selenium

31. - E7A07

What logical operation does a NAND gate perform?

Select	Answer
A	It produces logic 0 at its output only when all inputs are logic 1
B	It produces logic 1 at its output only when all inputs are logic 1
C	It produces logic 0 at its output only when all inputs are logic 0
D	It produces logic 0 at its output if some but not all inputs are logic 1

32. - E7B04

Where on the load line of a Class A common emitter amplifier would bias normally be set?

Select	Answer
A	Approximately halfway between saturation and cutoff
B	At a point where the bias resistor equals the load resistor
C	At a point where the load line intersects the zero bias current curve
D	Where the load line intersects the voltage axis

33. - E7C04

How does an impedance-matching circuit transform a complex impedance to a resistive impedance?

Select	Answer
A	It cancels the reactive part of the impedance and changes the resistive part to a desired value
B	It introduces transconductance to cancel the reactive part of impedance
C	It introduces negative resistance to cancel the resistive part of impedance
D	Reactive currents are dissipated in matched resistances

34. - E7D05

Which of the following types of linear voltage regulator places a constant load on the unregulated voltage source?

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

35. - E7E07

What is meant by the term "baseband" in radio communications?

Select	Answer
A	The basic oscillator frequency in an FM transmitter that is multiplied to increase the deviation and carrier frequency
B	The lowest frequency band that the transmitter or receiver covers
C	The unmodulated bandwidth of the transmitted signal
D	The frequency range occupied by a message signal prior to modulation

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 crystal-lattice filter
D	A phase-inverting filter

37. - E7G01

What is the typical output impedance of an op-amp?

Select	Answer
A	Very low
B	1000 ohms
C	Very high
D	100 ohms

38. - E7H11

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

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

39. - E8A11

Which of the following is a measure of the quality of an analog-to-digital converter?

Select	Answer
A	Reciprocal mixing
B	Total harmonic distortion
C	Power factor
D	Peak envelope power

40. - E8B09

What is deviation ratio?

Select	Answer
A	The ratio of the maximum carrier frequency deviation to the highest audio modulating frequency
B	The ratio of the audio modulating frequency to the center carrier frequency
C	The ratio of the carrier center frequency to the audio modulating frequency
D	The ratio of the highest audio modulating frequency to the average audio modulating frequency

41. - E8C07

What is the bandwidth of a 4800-Hz frequency shift, 9600-baud ASCII FM transmission?

Select	Answer
A	4.8 kHz
B	5.76 kHz
C	9.6 kHz
D	15.36 kHz

42. - E8D07

What is a common cause of overmodulation of AFSK signals?

Select	Answer
A	Ground loops
B	Excessive numbers of retries
C	Excessive transmit audio levels
D	Bit errors in the modem

43. - E9A07

What is the effective isotropic radiated power of a repeater station with 200 watts transmitter power output, 2 dB feed line loss, 2.8 dB duplexer loss, 1.2 dB circulator loss, and 7 dBi antenna gain?

Select	Answer
A	63.2 watts
B	159 watts
C	632 watts
D	252 watts

44. - E9B07

How does the total amount of radiation emitted by a directional gain antenna compare with the total amount of radiation emitted from a theoretical isotropic antenna, assuming each is driven by the same amount of power?

Select	Answer
A	The radiation from the isotropic antenna is 2.15 dB stronger than that from the directional antenna
B	They are the same
C	The total amount of radiation from the directional antenna is stronger by its front-to-back ratio
D	The total amount of radiation from the directional antenna is increased by the gain of the antenna

45. - E9C07

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

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

46. - E9D02

How can linearly polarized Yagi antennas be used to produce circular polarization?

Select	Answer
A	Stack two Yagis fed 90 degrees out of phase to form an array with the respective elements in parallel planes
B	Arrange two Yagis perpendicular to each other with the driven elements at the same point on the boom fed 90 degrees out of phase
C	Arrange two Yagis collinear to each other with the driven elements fed 180 degrees out of phase
D	Stack two Yagis fed in phase to form an array with the respective elements in parallel planes

47. - E9E09

Which of the following is used to shunt-feed a grounded tower at its base?

Select	Answer
A	Double-bazooka match
B	Gamma match
C	Hairpin match
D	All these choices are correct

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

49. - E9G03

Which of the following is often determined using a Smith chart?

Select	Answer
A	Satellite azimuth and elevation bearings
B	Beam headings and radiation patterns
C	Trigonometric functions
D	Impedance and SWR values in transmission lines

50. - E9H09

What is a Pennant antenna?

Select	Answer
A	A stealth antenna built to look like a flagpole
B	A four-element, high-gain vertical array invented by George Pennant
C	A form of rhombic antenna terminated in a variable capacitor to provide frequency diversity
D	A small, vertically oriented receiving antenna consisting of a triangular loop terminated in approximately 900 ohms