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

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1. - E0A07

How may dangerous levels of carbon monoxide from an emergency generator be detected?

Select	Answer
A	Only with a carbon monoxide detector
B	By the yellowish appearance of the gas
C	Any ordinary smoke detector can be used
D	By the odor

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	14.100 MHz
C	14.149 MHz
D	14.349 MHz

3. - E1B07

To what type of regulations does PRB-1 apply?

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

4. - E1C04

What is meant by IARP?

Select	Answer
A	An indication of increased antenna reflected power
B	An international amateur radio permit that allows U.S. amateurs to operate in certain countries of the Americas
C	The internal amateur radio practices policy of the FCC
D	A forecast of intermittent aurora radio propagation

5. - E1D04

Which of the following is required in the identification transmissions from a balloon-borne telemetry station?

Select	Answer
A	The station's six-character Maidenhead grid locator
B	The output power of the balloon transmitter
C	Call sign
D	All these choices are correct

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 70%
C	Minimum passing score of 74%
D	Minimum passing score of 77%

7. - E1F10

Who may be the control operator of an auxiliary station?

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

8. - E2A04

What is meant by the term mode? as applied to an amateur radio satellite?

Select	Answer
A	The satellite's orientation with respect to the Earth
B	Whether the satellite is in a polar or equatorial orbit
C	Whether the satellite is in a low earth or geostationary orbit
D	The satellite's uplink and downlink frequency bands

9. - E2B12

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

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

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 440 MHz transceiver with a 9600 baud modem
C	A 2 meter VHF transceiver with a 1200 baud modem
D	A wireless router running custom firmware

11. - E2D05

What is one advantage of the JT65 mode?

Select	Answer
A	The ability to decode signals which have a very low signal-to-noise ratio
B	Uses only a 65 Hz bandwidth
C	Easily copied by ear if necessary
D	Permits fast-scan TV transmissions over narrow bandwidth

12. - E2E06

What is the most common data rate used for HF packet?

Select	Answer
A	1200 baud
B	110 baud
C	48 baud
D	300 baud

13. - E3A14

What is meant by circularly polarized electromagnetic waves?

Select	Answer
A	Waves that circle the Earth
B	Waves with a rotating electric field
C	Waves produced by a loop antenna
D	Waves with an electric field bent into a circular shape

14. - E3B03

What is the best time of day for transequatorial propagation?

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

15. - E3C09

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

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

16. - E4A05

What is the purpose of the prescaler function on a frequency counter?

Select	Answer
A	It divides a higher frequency signal so a low-frequency counter can display the input frequency
B	It prevents oscillation in a low-frequency counter circuit
C	It amplifies low-level signals for more accurate counting
D	It multiplies a higher frequency signal so a low-frequency counter can display the operating frequency

17. - E4B02

What is the significance of voltmeter sensitivity expressed in ohms per volt?

Select	Answer
A	When used as a galvanometer, the reading in volts multiplied by the ohms per volt rating will determine the power drawn by the device under test
B	When used as an ammeter, the full scale reading in amps divided by ohms per volt rating will determine the size of shunt needed
C	The full scale reading of the voltmeter multiplied by its ohms per volt rating will indicate the input impedance of the voltmeter
D	When used as an ohmmeter, the reading in ohms divided by the ohms per volt rating will determine the voltage applied to the circuit

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 theoretical noise in a 1 Hz bandwidth at the input of a perfect receiver at room temperature
D	The noise figure of a 1 Hz bandwidth receiver

19. - E4D10

What does a third-order intercept level of 40 dBm mean with respect to receiver performance?

Select	Answer
A	A pair of 40 dBm input signals will theoretically generate a third-order intermodulation product that has the same output amplitude as either of the input signals
B	Signals less than 40 dBm will not generate audible third-order intermodulation products
C	A pair of 1 mW input signals will produce a third-order intermodulation product that is 40 dB stronger than the input signal
D	The receiver can tolerate signals up to 40 dB above the noise floor without producing third-order intermodulation products

20. - E4E05

How can radio frequency interference from an AC motor be suppressed?

Select	Answer
A	By installing a high-pass filter in series with the motor's power leads
B	By installing a brute-force AC-line filter in series with the motor leads
C	By using a ground-fault current interrupter in the circuit used to power the motor
D	By installing a bypass capacitor in series with the motor leads

21. - E5A15

Which of the following increases Q for inductors and capacitors?

Select	Answer
A	Lower reactance
B	Higher self-resonant frequency
C	Lower self-resonant frequency
D	Lower losses

22. - E5B09

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

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

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 phase angle and magnitude
D	By Y and G values

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

25. - E6A11

In Figure E6-1, what is the schematic symbol for a P-channel junction FET?

Select	Answer
A	3
B	1
C	2
D	6

26. - E6B08

Which of the following is a Schottky barrier diode?

Select	Answer
A	Electrolytic rectifier
B	PIN junction
C	Metal-semiconductor junction
D	Thermionic emission diode

27. - E6C04

Which of the following is an advantage of BiCMOS logic?

Select	Answer
A	All these choices are correct
B	It is immune to electrostatic damage
C	Its simplicity results in much less expensive devices than standard CMOS
D	It has the high input impedance of CMOS and the low output impedance of bipolar transistors

28. - E6D11

Which type of core material decreases inductance when inserted into a coil?

Select	Answer
A	Ceramic
B	Powdered iron
C	Brass
D	Ferrite

29. - E6E02

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

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

30. - E6F02

What happens to the conductivity of a photoconductive material when light shines on it?

Select	Answer
A	It decreases
B	It increases
C	It stays the same
D	It becomes unstable

31. - E7A11

What type of logic defines "1" as a high voltage?

Select	Answer
A	Assertive Logic
B	Positive Logic
C	Reverse Logic
D	Negative logic

32. - E7B10

In Figure E7-1, what is the purpose of R1 and R2?

Select	Answer
A	Load resistors
B	Voltage divider bias
C	Feedback
D	Self bias

33. - E7C10

Which of the following filters would be the best choice for use in a 2 meter band repeater duplexer?

Select	Answer
A	A DSP filter
B	A crystal filter
C	An L-C filter
D	A cavity filter

34. - E7D11

What is the function of the pass transistor in a linear voltage regulator circuit?

Select	Answer
A	Permits a wide range of output voltage settings
B	Provides a stable input impedance over a wide range of source voltage
C	Maintains nearly constant output voltage over a wide range of load current
D	Maintains nearly constant output impedance over a wide range of load current

35. - E7E02

What is the function of a reactance modulator?

Select	Answer
A	To produce AM signals by using an electrically variable inductance or capacitance
B	To produce PM or FM signals by using an electrically variable inductance or capacitance
C	To produce AM signals by using an electrically variable resistance
D	To produce PM 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	Mixing products are converted to voltages and subtracted by adder circuits
B	A frequency synthesizer removes the unwanted sidebands
C	Signals are combined in quadrature phase relationship
D	Varying quartz crystal characteristics emulated in digital form

37. - E7G11

What absolute voltage gain can be expected from the circuit in Figure E7-3 when R1 is 3300 ohms and RF is 47 kilohms?

Select	Answer
A	14
B	7
C	0.07
D	28

38. - E7H01

What are three oscillator circuits used in amateur radio equipment?

Select	Answer
A	Colpitts, Hartley and Pierce
B	Taft, Hartley and Pierce
C	Pierce, Fenner and Beane
D	Taft, Pierce and negative feedback

39. - E8A11

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

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

40. - E8B07

Orthogonal Frequency Division Multiplexing is a technique used for which type of amateur communication?

Select	Answer
A	High-speed digital modes
B	EME
C	OFDM signals are not allowed on amateur bands
D	Extremely low-power contacts

41. - E8C02

What is the definition of symbol rate in a digital transmission?

Select	Answer
A	The duration of each bit in a message sent over the air
B	The rate at which the waveform changes to convey information
C	The number of control characters in a message packet
D	The number of characters carried per second by the station-to-station link

42. - E8D08

What parameter evaluates distortion of an AFSK signal caused by excessive input audio levels?

Select	Answer
A	Baud rate
B	Repeat Request Rate (RRR)
C	Intermodulation Distortion (IMD)
D	Signal-to-noise ratio

43. - E9A09

What is antenna efficiency?

Select	Answer
A	Total resistance divided by radiation resistance
B	Radiation resistance divided by transmission resistance
C	Effective radiated power divided by transmitter output
D	Radiation resistance divided by total resistance

44. - E9B05

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

Select	Answer
A	Radiation resistance
B	Polarization
C	Elevation
D	Azimuth

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

46. - E9D03

Where should a high Q loading coil be placed to minimize losses in a shortened vertical antenna?

Select	Answer
A	At a voltage node
B	Near the center of the vertical radiator
C	As close to the transmitter as possible
D	As low as possible on the vertical radiator

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 delta matching system
B	The gamma matching system
C	The stub matching system
D	The omega matching system

48. - E9F06

What is the approximate physical length of an air-insulated, parallel conductor transmission line that is electrically 1/2 wavelength long at 14.10 MHz?

Select	Answer
A	8.5 meters
B	7.0 meters
C	13.3 meters
D	10.6 meters

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	Reactance axis
B	Prime axis
C	Impedance axis
D	Polar axis

50. - E9H04

What is an advantage of placing a grounded electrostatic shield around a small loop direction-finding antenna?

Select	Answer
A	It eliminates tracking errors caused by strong out-of-band signals
B	It eliminates unbalanced capacitive coupling to the surroundings, improving the nulls
C	It adds capacitive loading, increasing the bandwidth of the antenna
D	It increases signal strength by providing a better match to the feed line

Figure E6-1

Figure E7-1

Figure E7-3

Figure E9-2

Figure E9-3