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

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1. - E0A05

What is one of the potential hazards of operating in the amateur radio microwave bands?

Select	Answer
A	The high gain antennas commonly used can result in high exposure levels
B	Microwaves are ionizing radiation
C	The extremely high frequency energy can damage the joints of antenna structures
D	Microwaves often travel long distances by ionospheric reflection

2. - E1A02

When using a transceiver that displays the carrier frequency of phone signals, which of the following displayed frequencies represents the lowest frequency at which a properly adjusted LSB emission will be totally within the band?

Select	Answer
A	300 Hz above the lower band edge
B	1 kHz above the lower band edge
C	3 kHz above the lower band edge
D	The exact lower band edge

3. - E1B03

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

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

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

5. - E1D07

Which HF amateur bands have frequencies authorized for space stations?

Select	Answer
A	Only the 40, 20, 17, 15, and 10 meter bands
B	All HF bands
C	Only the 40, 20, 17, 15, 12, and 10 meter bands
D	Only the 40, 30, 20, 15, 12, and 10 meter bands

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 80%
C	Minimum passing score of 74%
D	Minimum passing score of 77%

7. - E1F06

Under what circumstances might the FCC issue a Special Temporary Authority (STA) to an amateur station?

Select	Answer
A	To provide temporary operation while awaiting normal licensing
B	To provide additional spectrum for personal use
C	To provide for experimental amateur communications
D	To allow regular operation on Land Mobile channels

8. - E2A13

Which of the following techniques is normally used by low Earth orbiting digital satellites to relay messages around the world?

Select	Answer
A	Store-and-forward
B	Digipeating
C	Node hopping
D	Multi-satellite relaying

9. - E2B07

What is the name of the signal component that carries color information in NTSC video?

Select	Answer
A	Luminance
B	Hue
C	Spectral intensity
D	Chroma

10. - E2C08

Which of the following contacts may be confirmed through the U.S. QSL bureau system?

Select	Answer
A	Special event contacts between stations in the U.S.
B	Repeater contacts between U.S. club members
C	Contacts between a U.S. station and a non-U.S. station
D	Contacts using tactical call signs

11. - E2D07

What digital protocol is used by APRS?

Select	Answer
A	AX.25
B	PACTOR
C	802.11
D	AMTOR

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	Your transmit frequency is incorrect
D	Another station you are unable to hear is using the frequency

13. - E3A08

When a meteor strikes the Earth's atmosphere, a cylindrical region of free electrons is formed at what layer of the ionosphere?

Select	Answer
A	The E layer
B	The F2 layer
C	The F1 layer
D	The D layer

14. - E3B03

What is the best time of day for transequatorial propagation?

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

15. - E3C08

What does the space weather term G5 mean?

Select	Answer
A	Waning sunspot numbers
B	Very low solar activity
C	An extreme geomagnetic storm
D	Moderate solar wind

16. - E4A11

How should an antenna analyzer be connected when measuring antenna resonance and feed point impedance?

Select	Answer
A	Connect the analyzer via a high-impedance transformer to the antenna
B	Loosely couple the analyzer near the antenna base
C	Loosely couple the antenna and a dummy load to the analyzer
D	Connect the antenna feed line directly to the analyzer's connector

17. - E4B05

What three test loads are used to calibrate an RF vector network analyzer?

Select	Answer
A	50 ohms through 1/8 wavelength, 1/4 wavelength, and 1/2 wavelength of coaxial cable
B	Short circuit, open circuit, and resonant circuit
C	50 ohms, 75 ohms, and 90 ohms
D	Short circuit, open circuit, and 50 ohms

18. - E4C12

Which of the following has the largest effect on an SDR receiver's dynamic range?

Select	Answer
A	RAM speed used for data storage
B	Analog-to-digital converter sample width in bits
C	CPU register width in bits
D	Anti-aliasing input filter bandwidth

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

20. - E4E07

Which of the following can cause shielded cables to radiate or receive interference?

Select	Answer
A	Use of braided shielding material
B	Low inductance ground connections at both ends of the shield
C	Tying all ground connections to a common point resulting in differential-mode currents in the shield
D	Common-mode currents on the shield and conductors

21. - E5A12

What is the half-power bandwidth of a resonant circuit that has a resonant frequency of 3.7 MHz and a Q of 118?

Select	Answer
A	218.3 kHz
B	31.4 kHz
C	436.6 kHz
D	15.7 kHz

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	14 degrees with the voltage lagging the current
C	14 degrees with the voltage leading the current
D	76 degrees with the voltage lagging the current

23. - E5C01

Which of the following represents capacitive reactance in rectangular notation?

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

24. - E5D12

How many watts are consumed in a circuit having a power factor of 0.2 if the input is 100 VAC at 4 amperes?

Select	Answer
A	400 watts
B	2000 watts
C	50 watts
D	80 watts

25. - E6A06

What is the beta of a bipolar junction transistor?

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

26. - E6B08

Which of the following is a Schottky barrier diode?

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

27. - E6C06

Why do CMOS digital integrated circuits have high immunity to noise on the input signal or power supply?

Select	Answer
A	The input switching threshold is about two times the power supply voltage
B	Bandwidth is very limited
C	Large bypass capacitance is inherent
D	The input switching threshold is about one-half the power supply voltage

28. - E6D05

What is one reason for using ferrite cores rather than powdered iron in an inductor?

Select	Answer
A	Ferrite toroids generally require fewer turns to produce a given inductance value
B	Ferrite toroids are easier to use with surface mount technology
C	Ferrite toroids generally have better temperature stability
D	Ferrite toroids generally have lower initial permeability

29. - E6E12

Why are DIP through-hole package ICs not typically used at UHF and higher frequencies?

Select	Answer
A	Unsuitable for combining analog and digital signals
B	Too many pins
C	Epoxy coating is conductive above 300 MHz
D	Excessive lead length

30. - E6F10

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

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

31. - E7A09

What logical operation is performed by an exclusive NOR gate?

Select	Answer
A	It produces logic 1 at its output only if all inputs are logic 1
B	It produces logic 0 at its output only if all inputs are logic 0
C	It produces logic 0 at its output if only one input is logic 1
D	It produces logic 1 at its output if only one input is logic 1

32. - E7B12

What type of amplifier circuit is shown in Figure E7-1?

Select	Answer
A	Emitter follower
B	Common emitter
C	Common collector
D	Common base

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

34. - E7D01

How does a linear electronic voltage regulator work?

Select	Answer
A	It eliminates the need for a pass transistor
B	The control element duty cycle is proportional to the line or load conditions
C	It has a ramp voltage as its output
D	The conduction of a control element is varied to maintain a constant output voltage

35. - E7E02

What is the function of a reactance modulator?

Select	Answer
A	To produce PM signals by using an electrically variable resistance
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 inductance or capacitance
D	To produce AM signals by using an electrically variable resistance

36. - E7F07

What function is performed by a Fast Fourier Transform?

Select	Answer
A	Converting analog signals to digital form
B	Converting digital signals from the time domain to the frequency domain
C	Converting digital signals to analog form
D	Converting 8-bit data to 16-bit data

37. - E7G06

What is the gain-bandwidth of an operational amplifier?

Select	Answer
A	The maximum frequency for a filter circuit using that type of amplifier
B	The frequency at which the open-loop gain of the amplifier equals one
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. - E7H11

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

Select	Answer
A	Broadband noise
B	Spurious signals at discrete frequencies
C	Nyquist limit 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	Total harmonic distortion
B	Peak envelope power
C	Reciprocal mixing
D	Power factor

40. - E8B01

What is the modulation index of an FM signal?

Select	Answer
A	The bandwidth of the transmitted signal divided by the modulating signal frequency
B	The ratio of frequency deviation to modulating signal frequency
C	The ratio of modulating signal amplitude to frequency deviation
D	The type of modulation used by the transmitter

41. - E8C04

What technique minimizes the bandwidth of a PSK31 signal?

Select	Answer
A	Reed-Solomon character encoding
B	Use of trapezoidal data pulses
C	Use of sinusoidal data pulses
D	Zero-sum character encoding

42. - E8D11

What is one advantage of using ASCII code for data communications?

Select	Answer
A	It uses one character as a shift code to send numeric and special characters
B	It includes built-in error correction features
C	It is possible to transmit both upper and lower case text
D	It contains fewer information bits per character than any other code

43. - E9A10

Which of the following improves the efficiency of a ground-mounted quarter-wave vertical antenna?

Select	Answer
A	Installing a radial system
B	All these choices are correct
C	Shortening the radiating element
D	Isolating the coax shield from ground

44. - E9B09

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

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

45. - E9C11

How is the far-field elevation pattern of a vertically polarized antenna affected by being mounted over seawater versus soil?

Select	Answer
A	The low-angle radiation decreases
B	Additional higher vertical angle lobes will appear
C	The low-angle radiation increases
D	Fewer vertical angle lobes will be present

46. - E9D10

What happens to feed-point impedance at the base of a fixed length HF mobile antenna when operated below its resonant frequency?

Select	Answer
A	The radiation resistance increases and the capacitive reactance increases
B	The radiation resistance decreases and the capacitive reactance increases
C	The radiation resistance decreases and the capacitive reactance decreases
D	The radiation resistance increases and the capacitive reactance decreases

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 stub match
B	The epsilon match
C	The delta match
D	The gamma match

48. - E9F13

What impedance does a 1/4-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 transmission line
B	Very low impedance
C	Very high impedance
D	The same as the generator output impedance

49. - E9G05

Which of the following is a common use for a Smith chart?

Select	Answer
A	Determine the gain of an antenna given the physical and electrical parameters
B	Determine the length and position of an impedance matching stub
C	Determine the loss/100 feet of a transmission line, given the velocity factor and conductor materials
D	Determine the impedance of a transmission line, given the physical dimensions

50. - E9H07

Why is RF attenuation used when direction-finding?

Select	Answer
A	To increase receiver sensitivity
B	To prevent receiver overload which reduces pattern nulls
C	To narrow the receiver bandwidth
D	To compensate for isotropic directivity and the antenna effect of feed lines

Figure E7-1