US Amateur Radio - Amateur Extra (Element 4, 2016-2020) Practice Test

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1. - E1A13

Who must be in physical control of the station apparatus of an amateur station aboard any vessel or craft that is documented or registered in the United States?

Select	Answer
A	Only a person named in an amateur station license grant
B	Any person holding an FCC issued amateur license or who is authorized for alien reciprocal operation
C	Any person named in an amateur station license grant or a person holding an unrestricted Radiotelephone Operator Permit
D	Only a person with an FCC Marine Radio

2. - 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
B	The amateur station must avoid transmitting during certain hours on frequencies that cause the interference
C	The amateur station must cease operation on all frequencies below 30 MHz
D	The amateur station must cease operation on all frequencies above 30 MHz

3. - E1C09

Which of these ranges of frequencies is available for an automatically controlled repeater operating below 30 MHz?

Select	Answer
A	18.110 MHz - 18.168 MHz
B	10.100 MHz - 10.150 MHz
C	24.940 MHz - 24.990 MHz
D	29.500 MHz - 29.700 MHz

4. - E1D04

What is an Earth station in the amateur satellite service?

Select	Answer
A	Any amateur station on the surface of the Earth
B	An amateur station within 50 km of the Earth's surface intended for communications with amateur stations by means of objects in space
C	An amateur station that transmits telemetry consisting of measurement of upper atmosphere
D	An amateur station that is not able to communicate using amateur satellites

5. - E1E08

To which of the following examinees may a VE not administer an examination?

Select	Answer
A	Employees of the VE
B	Friends of the VE
C	All of these choices are correct
D	Relatives of the VE as listed in the FCC rules

6. - E1F11

Which of the following best describes one of the standards that must be met by an external RF power amplifier if it is to qualify for a grant of FCC certification?

Select	Answer
A	It must be capable of external RF switching between its input and output networks
B	It must exhibit a gain of 0 dB or less over its full output range
C	It must satisfy the FCC's spurious emission standards when operated at the lesser of 1500 watts or its full output power
D	It must produce full legal output when driven by not more than 5 watts of mean RF input power

7. - E2A07

Which of the following types of signals can be relayed through a linear transponder?

Select	Answer
A	FM and CW
B	PSK and Packet
C	SSB and SSTV
D	All of these choices are correct

8. - E2B17

What is the approximate bandwidth of a slow-scan TV signal?

Select	Answer
A	2 MHz
B	6 MHz
C	3 kHz
D	600 Hz

9. - E2C04

What type of transmission is most often used for a ham radio mesh network?

Select	Answer
A	Store and forward on the 440 MHz band
B	Multiple Frequency Shift Keying in the 10 GHz band
C	Spread spectrum in the 2.4 GHz band
D	Frequency division multiplex in the 24 GHz band

10. - E2D03

Which of the following digital modes is especially useful for EME communications?

Select	Answer
A	JT65
B	Olivia
C	FSK441
D	PACTOR III

11. - E2E09

Which of the following HF digital modes uses variable-length coding for bandwidth efficiency?

Select	Answer
A	RTTY
B	MT63
C	PSK31
D	PACTOR

12. - E3A01

What is the approximate maximum separation measured along the surface of the Earth between two stations communicating by Moon bounce?

Select	Answer
A	5000 miles, if the Moon is at perigee
B	12,000 miles, if the Moon is visible by both stations
C	500 miles, if the Moon is at perigee
D	2000 miles, if the Moon is at apogee

13. - E3B13

Why is chordal hop propagation desirable?

Select	Answer
A	Signals travel faster along ionospheric chords
B	The MUF for chordal hop propagation is much lower than for normal skip propagation
C	Atmospheric noise is lower in the direction of chordal hop propagation
D	The signal experiences less loss along the path compared to normal skip propagation

14. - E3C12

How does the maximum distance of ground-wave propagation change when the signal frequency is increased?

Select	Answer
A	It peaks at roughly 14 MHz
B	It increases
C	It decreases
D	It stays the same

15. - E4A15

What is an advantage of a period-measuring frequency counter over a direct-count type?

Select	Answer
A	It does not require an expensive high-precision time base
B	It can run on battery power for remote measurements
C	It can directly measure the modulation index of an FM transmitter
D	It provides improved resolution of low-frequency signals within a comparable time period

16. - E4B17

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

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

17. - E4C08

An SDR receiver is overloaded when input signals exceed what level?

Select	Answer
A	The reference voltage of the analog-to-digital converter
B	The maximum count value of the analog-to-digital converter
C	One-half the maximum sample rate
D	One-half the maximum sampling buffer size

18. - E4D12

What is the term for the reduction in receiver sensitivity caused by a strong signal near the received frequency?

Select	Answer
A	Desensitization
B	Cross-modulation interference
C	Squelch gain rollback
D	Quieting

19. - E4E13

What might be the cause of a loud roaring or buzzing AC line interference that comes and goes at intervals?

Select	Answer
A	A defective doorbell or doorbell transformer inside a nearby residence
B	Arcing contacts in a thermostatically controlled device
C	A malfunctioning illuminated advertising display
D	All of these choices are correct

20. - E5A02

What is resonance in an electrical circuit?

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

21. - E5B09

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

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

22. - E5C16

Which point on Figure E5-2 best represents the impedance of a series circuit consisting of a 300 ohm resistor and a 19 picofarad capacitor at 21.200 MHz?

Select	Answer
A	Point 1
B	Point 8
C	Point 3
D	Point 7

23. - E5D15

What is the power factor of an R-L circuit having a 45 degree phase angle between the voltage and the current?

Select	Answer
A	1.0
B	0.866
C	0.707
D	0.5

24. - E6A02

Which of the following semiconductor materials contains excess free electrons?

Select	Answer
A	N-type
B	P-type
C	Insulated gate
D	Bipolar

25. - E6B02

What is an important characteristic of a Schottky diode as compared to an ordinary silicon diode when used as a power supply rectifier?

Select	Answer
A	Much higher reverse voltage breakdown
B	Less forward voltage drop
C	Controlled reverse avalanche voltage
D	Enhanced carrier retention time

26. - E6C02

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

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

27. - E6D07

What is the usable frequency range of inductors that use toroidal cores, assuming a correct selection of core material for the frequency being used?

Select	Answer
A	From about 100 kHz to at least 1000 GHz
B	From a few kHz to no more than 30 MHz
C	From approximately 10 Hz to no more than 3000 kHz
D	From less than 20 Hz to approximately 300 MHz

28. - E6E06

What characteristics of the MMIC make it a popular choice for VHF through microwave circuits?

Select	Answer
A	The ability to retrieve information from a single signal even in the presence of other strong signals
B	Nearly infinite gain, very high input impedance, and very low output impedance
C	Plate current that is controlled by a control grid
D	Controlled gain, low noise figure, and constant input and output impedance over the specified frequency range

29. - E6F01

What is photoconductivity?

Select	Answer
A	The decreased conductivity of an illuminated semiconductor
B	The increased conductivity of an illuminated semiconductor
C	The conversion of electromotive energy to photon energy
D	The conversion of photon energy to electromotive energy

30. - E7A01

Which is a bi-stable circuit?

Select	Answer
A	A flip-flop
B	An "AND" gate
C	A clock
D	An "OR" gate

31. - E7B15

What is one way to prevent thermal runaway in a bipolar transistor amplifier?

Select	Answer
A	Select transistors with high beta
B	All of these choices are correct
C	Use a resistor in series with the emitter
D	Neutralization

32. - E7C04

How does an impedance-matching circuit transform a complex impedance to a resistive impedance?

Select	Answer
A	It introduces negative resistance to cancel the resistive part of impedance
B	It introduces transconductance to cancel the reactive part of impedance
C	Network resistances are substituted for load resistances and reactances are matched to the resistances
D	It cancels the reactive part of the impedance and changes the resistive part to a desired value

33. - E7D14

What is one purpose of a "bleeder" resistor in a conventional unregulated power supply?

Select	Answer
A	To improve output voltage regulation
B	To balance the low-voltage filament windings
C	To boost the amount of output current
D	To cut down on waste heat generated by the power supply

34. - E7E01

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

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

35. - E7F06

What is the minimum number of bits required for an analog-to-digital converter to sample a signal with a range of 1 volt at a resolution of 1 millivolt?

Select	Answer
A	6 bits
B	8 bits
C	4 bits
D	10 bits

36. - E7G06

Which of the following is the most appropriate use of an op-amp active filter?

Select	Answer
A	As a low-pass filter used between a transmitter and a transmission line
B	For smoothing power supply output
C	As an audio filter in a receiver
D	As a high-pass filter used to block RFI at the input to receivers

37. - E7H04

How is positive feedback supplied in a Colpitts oscillator?

Select	Answer
A	Through a capacitive divider
B	Through a tapped coil
C	Through link coupling
D	Through a neutralizing capacitor

38. - E8A03

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

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

39. - E8B08

What describes Orthogonal Frequency Division Multiplexing?

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

40. - E8C10

What is an advantage of Gray code in digital communications where symbols are transmitted as multiple bits

Select	Answer
A	It has more resolution than simple binary
B	It facilitates error detection
C	It increases security
D	It has more possible states than simple binary

41. - E8D10

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

Select	Answer
A	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
B	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
C	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
D	Baudot uses 7 data bits per character, ASCII uses 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes

42. - E9A13

How much gain does an antenna have compared to a 1/2-wavelength dipole when it has 12 dB gain over an isotropic antenna?

Select	Answer
A	14.15 dB
B	9.85 dB
C	12.5 dB
D	6.17 dB

43. - E9B10

What is the principle of a Method of Moments analysis?

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

44. - E9C02

What is the radiation pattern of two 1/4 wavelength vertical antennas spaced 1/4 wavelength apart and fed 90 degrees out of phase?

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

45. - E9D11

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

Select	Answer
A	A single 12 gauge or 10 gauge stainless steel wire
B	A resistive wire, such as spark plug wire
C	A cable with six or seven 18 gauge conductors in parallel
D	A wide flat copper strap

46. - 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 stub matching system
B	The omega matching system
C	The gamma matching system
D	The delta matching system

47. - E9F03

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

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

48. - E9G07

On the Smith chart shown in Figure E9-3, what is the only straight line shown?

Select	Answer
A	The current axis
B	The resistance axis
C	The reactance axis
D	The voltage axis

49. - 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 provides diversity reception that cancels multipath signals
C	It modifies the pattern of a DF antenna array to provide a null in one direction
D	It increases the sensitivity of a DF antenna array

50. - E0A01

What is the primary function of an external earth connection or ground rod?

Select	Answer
A	Reduce received noise
B	Reduce RF current flow between pieces of equipment
C	Reduce RFI to telephones and home entertainment systems
D	Lightning protection

Figure E5-2

Figure E9-3