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

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1. - E0A08

What does SAR measure?

Select	Answer
A	The rate of RF energy reflected from stationary terrain
B	Synthetic Aperture Ratio of the human body
C	Signal Amplification Rating
D	The rate at which RF energy is absorbed by the body

2. - E1A06

Where must the carrier frequency of a CW signal be set to comply with FCC rules for 60 meter operation?

Select	Answer
A	At the center frequency of the channel
B	On any frequency where the signal's sidebands are within the channel
C	At the lowest frequency of the channel
D	At the highest frequency of the channel

3. - E1B03

Within what distance must an amateur station protect an FCC monitoring facility from harmful interference?

Select	Answer
A	30 miles
B	3 miles
C	1 mile
D	10 miles

4. - E1C01

What is the maximum bandwidth for a data emission on 60 meters?

Select	Answer
A	1.5 kHz
B	2.8 kHz
C	170 Hz
D	60 Hz

5. - E1D03

What is a space telecommand station?

Select	Answer
A	An amateur station that transmits communications to initiate, modify or terminate functions of a space station
B	An amateur station that receives telemetry from a satellite or balloon more than 50 kilometers above the surface of the Earth
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. - E1E01

For which types of out-of-pocket expenses do the Part 97 rules state that VEs and VECs may be reimbursed?

Select	Answer
A	Preparing, processing, administering, and coordinating an examination for an amateur radio operator license
B	Teaching an amateur operator license examination preparation course
C	No expenses are authorized for reimbursement
D	Providing amateur operator license examination preparation training materials

7. - E1F02

What privileges are authorized in the U.S. to persons holding an amateur service license granted by the government of Canada?

Select	Answer
A	All privileges of the Amateur Extra Class license
B	None, they must obtain a U.S. license
C	The operating terms and conditions of the Canadian amateur service license, not to exceed U.S. Amateur Extra Class license privileges
D	Full privileges, up to and including those of the Amateur Extra Class license, on the 80, 40, 20, 15, and 10 meter bands

8. - E2A11

What type of antenna can be used to minimize the effects of spin modulation and Faraday rotation?

Select	Answer
A	An isotropic antenna
B	A circularly polarized antenna
C	A linearly polarized antenna
D	A log-periodic dipole array

9. - E2B06

What is vestigial sideband modulation?

Select	Answer
A	A type of modulation in which one sideband is inverted
B	Narrow-band FM modulation achieved by filtering one sideband from the audio before frequency modulating the carrier
C	Spread spectrum modulation achieved by applying FM modulation following single sideband amplitude modulation
D	Amplitude modulation in which one complete sideband and a portion of the other are transmitted

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

11. - E2D02

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

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

12. - E2E01

Which of the following types of modulation is common for data emissions below 30 MHz?

Select	Answer
A	DTMF tones modulating an FM signal
B	Pulse modulation
C	FSK
D	Spread spectrum

13. - E3A11

What is a typical range for tropospheric propagation of microwave signals?

Select	Answer
A	2500 miles
B	10 miles to 50 miles
C	1200 miles
D	100 miles to 300 miles

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 solstices, especially the summer solstice
C	Around the equinoxes, especially the fall equinox
D	Around the equinoxes, especially the spring equinox

15. - E3C09

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

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

16. - E4A06

What is the effect of aliasing on a digital oscilloscope caused by setting the time base too slow?

Select	Answer
A	Excessive blanking occurs, which prevents display of the signal
B	All signals will have a DC offset
C	A false, jittery low-frequency version of the signal is displayed
D	Calibration of the vertical scale is no longer valid

17. - E4B02

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

Select	Answer
A	When used as an ohmmeter, the reading in ohms divided by the ohms per volt rating will determine the voltage applied to the circuit
B	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
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 ammeter, the full scale reading in amps divided by ohms per volt rating will determine the size of shunt needed

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	15.210 MHz
B	14.755 MHz
C	13.845 MHz
D	14.445 MHz

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	Intermodulation
B	Neutralization
C	Adjacent channel interference
D	Amplifier desensitization

20. - E4E09

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

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

21. - E5A04

What is the magnitude of the impedance of a parallel RLC circuit at resonance?

Select	Answer
A	Approximately equal to inductive reactance
B	Approximately equal to circuit resistance
C	High compared to the circuit resistance
D	Low compared to the circuit resistance

22. - E5B10

What is the relationship between the AC current through an inductor and the voltage across an inductor?

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

23. - E5C01

Which of the following represents capacitive reactance in rectangular notation?

Select	Answer
A	Omega
B	Delta
C	-jX
D	+jX

24. - E5D01

What is the result of skin effect?

Select	Answer
A	As frequency decreases, RF current flows in a thinner layer of the conductor, closer to the surface
B	Thermal effects on the surface of the conductor increase the impedance
C	Thermal effects on the surface of the conductor decrease the impedance
D	As frequency increases, RF current flows in a thinner layer of the conductor, closer to the surface

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 breakdown voltage of the base to collector junction
C	The switching speed
D	The frequency at which the current gain is reduced to 0.707

26. - E6B03

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

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

27. - E6C01

What is the function of hysteresis in a comparator?

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

28. - E6D07

What is current in the primary winding of a transformer called if no load is attached to the secondary?

Select	Answer
A	Direct current
B	Stabilizing current
C	Excitation current
D	Magnetizing current

29. - E6E11

What is a characteristic of DIP packaging used for integrated circuits?

Select	Answer
A	A total of two rows of connecting pins placed on opposite sides of the package (Dual In-line Package)
B	Two chips in each package (Dual In Package)
C	Package mounts in a direct inverted position
D	Low leakage doubly insulated package

30. - E6F08

Why are optoisolators often used in conjunction with solid-state circuits when switching 120 VAC?

Select	Answer
A	Optoisolators provide a low impedance link between a control circuit and a power circuit
B	Optoisolators eliminate the effects of reflected light in the control circuit
C	Optoisolators provide impedance matching between the control circuit and power circuit
D	Optoisolators provide a very high degree of electrical isolation between a control circuit and the circuit being switched

31. - E7A11

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

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

32. - E7B09

Which of the following describes how the loading and tuning capacitors are to be adjusted when tuning a vacuum tube RF power amplifier that employs a Pi-network output circuit?

Select	Answer
A	The loading capacitor is adjusted to minimum plate current while alternately adjusting the tuning capacitor for maximum allowable plate current
B	The tuning capacitor is adjusted for minimum plate current, and the loading capacitor is adjusted for maximum permissible plate current
C	The tuning capacitor is set to maximum capacitance and the loading capacitor is adjusted for minimum plate permissible current
D	The loading capacitor is set to maximum capacitance and the tuning capacitor is adjusted for minimum allowable plate current

33. - E7C08

Which of the following factors has the greatest effect on the bandwidth and response shape of a crystal ladder filter?

Select	Answer
A	The gain of the RF stage preceding the filter
B	The relative frequencies of the individual crystals
C	The DC voltage applied to the quartz crystal
D	The amplitude of the signals passing through the filter

34. - E7D15

What is the purpose of a step-start circuit in a high-voltage power supply?

Select	Answer
A	To provide a dual-voltage output for reduced power applications
B	To allow for remote control of the power supply
C	To compensate for variations of the incoming line voltage
D	To allow the filter capacitors to charge gradually

35. - E7E04

What is one way a single-sideband phone signal can be generated?

Select	Answer
A	By using a balanced modulator followed by a filter
B	By using a reactance modulator followed by a mixer
C	By using a loop modulator followed by a mixer
D	By driving a product detector with a DSB signal

36. - E7F10

What aspect of receiver analog-to-digital conversion determines the maximum receive bandwidth of a Direct Digital Conversion SDR?

Select	Answer
A	Sample width in bits
B	Sample clock phase noise
C	Processor latency
D	Sample rate

37. - E7G06

What is the gain-bandwidth of an operational amplifier?

Select	Answer
A	The frequency at which the open-loop gain of the amplifier equals one
B	The maximum frequency for a filter circuit using that type of amplifier
C	The frequency at which the amplifier's offset voltage is zero
D	The gain of the amplifier at a filter's cutoff frequency

38. - E7H01

What are three oscillator circuits used in amateur radio equipment?

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

39. - E8A03

What type of wave does a Fourier analysis show to be made up of sine waves of a given fundamental frequency plus all its harmonics?

Select	Answer
A	A sawtooth wave
B	A cosine wave
C	A sine wave
D	A square wave

40. - E8B08

What describes Orthogonal Frequency Division Multiplexing?

Select	Answer
A	A bandwidth compression technique using Fourier transforms
B	A digital mode for narrow-band, slow-speed transmissions
C	A frequency modulation technique that uses non-harmonically related frequencies
D	A digital modulation technique using subcarriers at frequencies chosen to avoid intersymbol interference

41. - E8C12

What factors affect the bandwidth of a transmitted CW signal?

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

42. - E8D10

What are some of the differences between the Baudot digital code and ASCII?

Select	Answer
A	Baudot uses 7 data bits per character, ASCII uses 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes
B	Baudot uses 6 data bits per character, ASCII uses 7 or 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes
C	Baudot uses 5 data bits per character, ASCII uses 7 or 8; Baudot uses 2 characters as letters/figures shift codes, ASCII has no letters/figures shift code
D	Baudot uses 4 data bits per character, ASCII uses 7 or 8; Baudot uses 1 character as a letters/figures shift code, ASCII has no letters/figures code

43. - E9A05

What is included in the total resistance of an antenna system?

Select	Answer
A	Radiation resistance plus transmission resistance
B	Transmission-line resistance plus radiation resistance
C	Radiation resistance plus loss resistance
D	Radiation resistance plus space impedance

44. - E9B10

What is the principle of a Method of Moments analysis?

Select	Answer
A	A wire is modeled as a single sine-wave current generator
B	A wire is modeled as a series of segments, each having a uniform value of current
C	A wire is modeled as a single sine-wave voltage source
D	A wire is modeled as a series of segments, each having a distinct value of voltage across it

45. - E9C07

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

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

46. - E9D07

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

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

47. - E9E08

What is a use for a Wilkinson divider?

Select	Answer
A	It is used to feed low-impedance loads from a high-impedance source
B	It is used to feed high-impedance antennas from a low-impedance source
C	It divides the operating frequency of a transmitter signal so it can be used on a lower frequency band
D	It is used to divide power equally between two 50-ohm loads while maintaining 50-ohm input impedance

48. - E9F12

What impedance does a 1/4-wavelength transmission line present to a generator when the line is open at the far end?

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

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	Impedance axis
B	Prime axis
C	Polar axis
D	Reactance axis

50. - E9H10

How can the output voltage of a multiple-turn receiving loop antenna be increased?

Select	Answer
A	By reducing the permeability of the loop shield
B	By increasing the number of turns and/or the area
C	By winding adjacent turns in opposing directions
D	By utilizing high impedance wire for the coupling loop

Figure E9-3