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	Mica
D	Zinc oxide

2. - E1A03

What is the maximum legal carrier frequency on the 20 meter band for transmitting USB AFSK digital signals having a 1 kHz bandwidth?

Select	Answer
A	14.070 MHz
B	14.349 MHz
C	14.149 MHz
D	14.100 MHz

3. - E1B07

To what type of regulations does PRB-1 apply?

Select	Answer
A	FAA tower height limits
B	Use of wireless devices in vehicles
C	State and local zoning
D	Homeowners associations

4. - E1C07

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

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

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. - E1E05

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

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

7. - E1F07

When may an amateur station send a message to a business?

Select	Answer
A	When the control operator is employed by the FCC or another government agency
B	When transmitting international third-party communications
C	When the total money involved does not exceed $25
D	When neither the amateur nor his or her employer has a pecuniary interest in the communications

8. - E2A08

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

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

9. - E2B08

What technique allows commercial analog TV receivers to be used for fast-scan TV operations on the 70 cm band?

Select	Answer
A	Transmitting on the abandoned TV channel 2
B	Transmitting on channels shared with cable TV
C	Using converted satellite TV dishes
D	Using USB and demodulating the signal with a computer sound card

10. - E2C11

How should you generally identify your station when attempting to contact a DX station during a contest or in a pileup?

Select	Answer
A	Send only the last two letters of your call sign until you make contact
B	Send your full call sign once or twice
C	Send your full call sign and grid square
D	Send the call sign of the DX station three times, the words this is,then your call sign three times

11. - E2D02

Which of the following is a good technique for making meteor scatter contacts?

Select	Answer
A	All these choices are correct
B	15-second timed transmission sequences with stations alternating based on location
C	Use of special digital modes
D	Short transmissions with rapidly repeated call signs and signal reports

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

13. - E3A07

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

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

14. - E3B04

What is meant by the terms "extraordinary" and "ordinary" waves?

Select	Answer
A	Refracted rays and reflected waves
B	Independent waves created in the ionosphere that are elliptically polarized
C	Long-path and short-path waves
D	Extraordinary waves describe rare long-skip propagation compared to ordinary waves, which travel shorter distances

15. - E3C07

Which of the following descriptors indicates the greatest solar flare intensity?

Select	Answer
A	Class A
B	Class X
C	Class B
D	Class M

16. - E4A08

Which of the following measures SWR?

Select	Answer
A	A Q meter
B	A spectrum analyzer
C	An antenna analyzer
D	An ohmmeter

17. - E4B07

What do the subscripts of S parameters represent?

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

18. - E4C14

What transmit frequency might generate an image response signal in a receiver tuned to 14.300 MHz and that uses a 455 kHz IF frequency?

Select	Answer
A	13.845 MHz
B	14.445 MHz
C	14.755 MHz
D	15.210 MHz

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

20. - E4E01

What problem can occur when using an automatic notch filter (ANF) to remove interfering carriers while receiving CW signals?

Select	Answer
A	Received CW signals will appear to be modulated at the DSP clock frequency
B	Removal of the CW signal as well as the interfering carrier
C	Ringing in the DSP filter will completely remove the spaces between the CW characters
D	Any nearby signal passing through the DSP system will overwhelm the desired signal

21. - E5A02

What is resonance in an LC or RLC circuit?

Select	Answer
A	The lowest frequency that will pass current
B	The frequency at which the capacitive reactance equals the inductive reactance
C	The frequency at which the reactive impedance equals the resistive impedance
D	The highest frequency that will pass current

22. - E5B03

How is impedance in polar form converted to an equivalent admittance?

Select	Answer
A	Take the reciprocal of the magnitude and change the sign of the angle
B	Take the square root of the magnitude and add 180 degrees to the angle
C	Take the reciprocal of the angle and change the sign of the magnitude
D	Square the magnitude and subtract 90 degrees from the angle

23. - E5C03

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

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

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

25. - E6A08

What term indicates the frequency at which the grounded-base current gain of a transistor has decreased to 0.7 of the gain obtainable at 1 kHz?

Select	Answer
A	Beta cutoff frequency
B	Corner frequency
C	Alpha cutoff frequency
D	Alpha rejection frequency

26. - E6B01

What is the most useful characteristic of a Zener diode?

Select	Answer
A	A constant current drop under conditions of varying voltage
B	A negative resistance region
C	A constant voltage drop under conditions of varying current
D	An internal capacitance that varies with the applied voltage

27. - E6C08

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

Select	Answer
A	4
B	1
C	2
D	3

28. - E6D12

What is inductor saturation?

Select	Answer
A	The inductor's voltage rating is exceeded causing a flashover
B	The inductor windings are over-coupled
C	Adjacent inductors become over-coupled
D	The ability of the inductor's core to store magnetic energy has been exceeded

29. - E6E10

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

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

30. - E6F05

Which describes an optical shaft encoder?

Select	Answer
A	A device for generating RTTY signals by means of a rotating light source
B	A device that measures the strength of a beam of light using analog to digital conversion
C	A device that detects rotation of a control by interrupting a light source with a patterned wheel
D	A digital encryption device often used to encrypt spacecraft control signals

31. - E7A05

Which of the following is a circuit that continuously alternates between two states without an external clock?

Select	Answer
A	Astable multivibrator
B	Monostable multivibrator
C	J-K flip-flop
D	T flip-flop

32. - E7B08

How can an RF power amplifier be neutralized?

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

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

34. - E7D06

What is the purpose of Q1 in the circuit shown in Figure E7-2?

Select	Answer
A	It provides D1 with current
B	It controls the current supplied to the load
C	It provides a constant load for the voltage source
D	It provides negative feedback to improve regulation

35. - E7E07

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

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

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 can delay all frequency components of the signal by the same amount
C	FIR filters are easier to implement for a given set of passband rolloff requirements
D	FIR filters can respond faster to impulses

37. - E7G01

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

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

38. - E7H14

What is a phase-locked loop circuit?

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

39. - E8A07

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

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

40. - E8B05

What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus-or-minus 5 kHz when the maximum modulation frequency is 3 kHz?

Select	Answer
A	60
B	0.167
C	1.67
D	0.6

41. - E8C03

Why should phase-shifting of a PSK signal be done at the zero crossing of the RF signal?

Select	Answer
A	To minimize bandwidth
B	To simplify modulation
C	To improve carrier suppression
D	All these choices are correct

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. - E9A13

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

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

44. - E9B09

What type of computer program technique is commonly used for modeling antennas?

Select	Answer
A	Graphical analysis
B	Method of Moments
C	Calculus differentiation with respect to physical properties
D	Mutual impedance analysis

45. - E9C01

What is the radiation pattern of two 1/4-wavelength vertical antennas spaced 1/2-wavelength apart and fed 180 degrees out of phase?

Select	Answer
A	Cardioid
B	A figure-8 oriented along the axis of the array
C	A figure-8 broadside to the axis of the array
D	Omni-directional

46. - E9D11

Which of the following conductors would be best for minimizing losses in a station's RF ground system?

Select	Answer
A	Resistive wire, such as spark plug wire
B	Solid wire
C	Wide flat copper strap
D	Stranded wire

47. - E9E06

Which of these feed line impedances would be suitable for constructing a quarter-wave Q-section for matching a 100-ohm loop to 50-ohm feed line?

Select	Answer
A	50 ohms
B	75 ohms
C	62 ohms
D	450 ohms

48. - E9F03

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

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

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	Prime axis
B	Polar axis
C	Reactance axis
D	Impedance axis

50. - E9H06

What is the triangulation method of direction finding?

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

Figure E6-3

Figure E7-2

Figure E9-3