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	3 to 30 MHz
B	30 to 300 MHz
C	300 kHz to 3 MHz
D	300 to 3000 MHz

2. - E1A11

Which of the following describes authorization or licensing required when operating an amateur station aboard a U.S.-registered vessel in international waters?

Select	Answer
A	Any FCC-issued amateur license
B	Only General Class or higher amateur licenses
C	An unrestricted Radiotelephone Operator Permit
D	Any amateur license with an FCC Marine or Aircraft endorsement

3. - E1B08

What limitations may the FCC place on an amateur station if its signal causes interference to domestic broadcast reception, assuming that the receivers involved are of good engineering design?

Select	Answer
A	The amateur station must cease operation on all frequencies below 30 MHz
B	The amateur station must cease operation on all frequencies above 30 MHz
C	The amateur station must cease operation
D	The amateur station must avoid transmitting during certain hours on frequencies that cause the interference

4. - E1C03

How do the control operator responsibilities of a station under automatic control differ from one under local control?

Select	Answer
A	Under automatic control there is no control operator
B	Under automatic control the control operator is not required to be present at the control point
C	Under local control there is no control operator
D	Under local control a control operator is not required to be present at a control point

5. - E1D11

Which amateur stations are eligible to operate as Earth stations?

Select	Answer
A	Any amateur station, subject to the privileges of the class of operator license held by the control operator
B	Any amateur station whose licensee has filed a pre-space notification with the FCC's International Bureau
C	Only those of Amateur Extra Class operators
D	Only those of General, Advanced or Amateur Extra Class operators

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

7. - E1F09

Which of the following conditions apply when transmitting spread spectrum emissions?

Select	Answer
A	A station transmitting SS emission must not cause harmful interference to other stations employing other authorized emissions
B	The transmitting station must be in an area regulated by the FCC or in a country that permits SS emissions
C	All these choices are correct
D	The transmission must not be used to obscure the meaning of any communication

8. - E2A11

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

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

9. - E2B03

How is an interlaced scanning pattern generated in a fast-scan (NTSC) television system?

Select	Answer
A	By scanning lines from left to right in one field and right to left in the next
B	By scanning each field from bottom to top
C	By scanning odd numbered lines in one field and even numbered lines in the next
D	By scanning two fields simultaneously

10. - E2C12

What technique do individual nodes use to form a mesh network?

Select	Answer
A	Forward error correction and Viterbi codes
B	Discovery and link establishment protocols
C	Custom code plugs for the local trunking systems
D	Acting as store-and-forward digipeaters

11. - E2D02

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

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

12. - E2E11

What is the difference between direct FSK and audio FSK?

Select	Answer
A	Direct FSK can transmit faster baud rates
B	Only direct FSK can be decoded by computer
C	Direct FSK occupies less bandwidth
D	Direct FSK applies the data signal to the transmitter VFO, while AFSK transmits tones via phone

13. - E3A13

Which of these emission modes is best for auroral propagation?

Select	Answer
A	FM
B	SSB
C	RTTY
D	CW

14. - E3B04

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

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

15. - E3C11

What does VOACAP software model?

Select	Answer
A	AC voltage and impedance
B	HF propagation
C	AC current and impedance
D	VHF radio propagation

16. - E4A06

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

Select	Answer
A	All signals will have a DC offset
B	A false, jittery low-frequency version of the signal is displayed
C	Excessive blanking occurs, which prevents display of the signal
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 ammeter, the full scale reading in amps divided by ohms per volt rating will determine the size of shunt needed
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 ohmmeter, the reading in ohms divided by the ohms per volt rating will determine the voltage applied to the circuit

18. - E4C15

What is reciprocal mixing?

Select	Answer
A	In-phase signals cancelling in a mixer resulting in loss of receiver sensitivity
B	Two out-of-band signals mixing to generate an in-band spurious signal
C	Two digital signals combining from alternate time slots
D	Local oscillator phase noise mixing with adjacent strong signals to create interference to desired signals

19. - E4D05

What transmitter frequencies would cause an intermodulation-product signal in a receiver tuned to 146.70 MHz when a nearby station transmits on 146.52 MHz?

Select	Answer
A	146.34 MHz and 146.61 MHz
B	146.10 MHz and 147.30 MHz
C	173.35 MHz and 139.40 MHz
D	146.88 MHz and 146.34 MHz

20. - E4E01

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

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

21. - E5A10

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

Select	Answer
A	Reactance of the inductance multiplied by the reactance of the capacitance
B	Reactance of either the inductance or capacitance multiplied by the resistance
C	Resistance divided by the reactance of either the inductance or capacitance
D	Reactance of either the inductance or capacitance divided 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 leading the current
B	76 degrees with the voltage lagging the current
C	14 degrees with the voltage lagging the current
D	14 degrees with the voltage leading the current

23. - E5C07

Where is the impedance of a pure resistance plotted on rectangular coordinates?

Select	Answer
A	On a line through the origin, slanted at 45 degrees
B	On a horizontal line, offset vertically above the horizontal axis
C	On the vertical axis
D	On the horizontal axis

24. - E5D08

How many watts are consumed in a circuit having a power factor of 0.6 if the input is 200VAC at 5 amperes?

Select	Answer
A	200 watts
B	1600 watts
C	600 watts
D	1000 watts

25. - E6A06

What is the beta of a bipolar junction transistor?

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

26. - E6B09

What is a common use for point-contact diodes?

Select	Answer
A	As a high-voltage rectifier
B	As a constant voltage source
C	As a constant current source
D	As an RF detector

27. - E6C02

What happens when the level of a comparator's input signal crosses the threshold?

Select	Answer
A	The feedback loop becomes unstable
B	The comparator changes its output state
C	The comparator enters latch-up
D	The IC input can be damaged

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

29. - E6E07

What type of transmission line is used for connections to MMICs?

Select	Answer
A	Microstrip
B	Miniature coax
C	Parallel wire
D	Circular waveguide

30. - E6F10

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

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

31. - E7A01

Which circuit is bistable?

Select	Answer
A	A flip-flop
B	An OR gate
C	An AND gate
D	A bipolar amplifier

32. - E7B14

Why are switching amplifiers more efficient than linear amplifiers?

Select	Answer
A	The power transistor is at saturation or cutoff most of the time
B	Linear amplifiers have high gain resulting in higher harmonic content
C	Switching amplifiers operate at higher voltages
D	Switching amplifiers use push-pull circuits

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

34. - E7D08

What type of circuit is shown in Figure E7-2?

Select	Answer
A	Monostable multivibrator
B	Switching voltage regulator
C	Linear voltage regulator
D	Grounded emitter amplifier

35. - E7E01

Which of the following can be used to generate FM phone emissions?

Select	Answer
A	A reactance modulator on the oscillator
B	A balanced modulator on the audio amplifier
C	A reactance modulator on the final amplifier
D	A balanced modulator on the oscillator

36. - E7F03

What type of digital signal processing filter is used to generate an SSB signal?

Select	Answer
A	An elliptical filter
B	A notch filter
C	A Hilbert-transform filter
D	An adaptive filter

37. - E7G04

What is meant by the "op-amp input offset voltage"?

Select	Answer
A	The output voltage of the op-amp minus its input voltage
B	The difference between the output voltage of the op-amp and the input voltage required in the immediately following stage
C	The potential between the amplifier input terminals of the op-amp in an open loop condition
D	The differential input voltage needed to bring the open loop output voltage to zero

38. - E7H15

Which of these functions can be performed by a phase-locked loop?

Select	Answer
A	Frequency synthesis, FM demodulation
B	Comparison of two digital input signals, digital pulse counter
C	Wide-band AF and RF power amplification
D	Photovoltaic conversion, optical coupling

39. - E8A11

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

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

40. - E8B11

What is digital time division multiplexing?

Select	Answer
A	Two or more data streams share the same channel by transmitting time of transmission as the sub-carrier
B	Two or more signals are arranged to share discrete time slots of a data transmission
C	Two or more signals are quadrature modulated to increase bandwidth efficiency
D	Two or more data streams are assigned to discrete sub-carriers on an FM transmitter

41. - E8C05

What is the approximate bandwidth of a 13-WPM International Morse Code transmission?

Select	Answer
A	26 Hz
B	104 Hz
C	13 Hz
D	52 Hz

42. - E8D06

What is the advantage of including parity bits in ASCII characters?

Select	Answer
A	Foreign language characters can be sent
B	Some types of errors can be detected
C	Faster transmission rate
D	The signal can overpower interfering signals

43. - E9A12

How much gain does an antenna have compared to a 1/2-wavelength dipole when it has 6 dB gain over an isotropic antenna?

Select	Answer
A	6.0 dB
B	2.79 dB
C	8.15 dB
D	3.85 dB

44. - E9B02

In the antenna radiation pattern shown in Figure E9-1, what is the front-to-back ratio?

Select	Answer
A	36 dB
B	14 dB
C	18 dB
D	24 dB

45. - E9C06

What is the effect of adding a terminating resistor to a rhombic antenna?

Select	Answer
A	It decreases the ground loss
B	It changes the radiation pattern from horizontal to vertical polarization
C	It reflects the standing waves on the antenna elements back to the transmitter
D	It changes the radiation pattern from bidirectional to unidirectional

46. - E9D02

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

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

47. - E9E02

What is the name of an antenna matching system that matches an unbalanced feed line to an antenna by feeding the driven element both at the center of the element and at a fraction of a wavelength to one side of center?

Select	Answer
A	The delta match
B	The epsilon match
C	The gamma match
D	The stub match

48. - E9F07

How does ladder line compare to small-diameter coaxial cable such as RG-58 at 50 MHz?

Select	Answer
A	Lower velocity factor
B	Higher SWR
C	Lower loss
D	Smaller reflection coefficient

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. - E9H08

What is the function of a sense antenna?

Select	Answer
A	It allows DF antennas to receive signals at different vertical angles
B	It modifies the pattern of a DF antenna array to provide a null in one direction
C	It increases the sensitivity of a DF antenna array
D	It provides diversity reception that cancels multipath signals

Figure E7-2

Figure E9-1

Figure E9-3