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

2. - E1A05

What is the maximum power output permitted on the 60 meter band?

Select	Answer
A	50 watts PEP effective radiated power relative to an isotropic radiator
B	100 watts PEP effective radiated power relative to an isotropic radiator
C	100 watts PEP effective radiated power relative to the gain of a half-wave dipole
D	50 watts PEP effective radiated power relative to a dipole

3. - E1B02

Which of the following is an acceptable bandwidth for Digital Radio Mondiale (DRM) based voice or SSTV digital transmissions made on the HF amateur bands?

Select	Answer
A	3 kHz
B	15 kHz
C	10 kHz
D	20 kHz

4. - E1C14

How long must an operator wait after filing a notification with the Utilities Technology Council (UTC) before operating on the 2200 meter or 630 meter band?

Select	Answer
A	Operators may not operate until a test signal has been transmitted in coordination with the local power company
B	Operators may operate after 30 days, providing they have not been told that their station is within 1 km of PLC systems using those frequencies
C	Operations may commence immediately, and may continue unless interference is reported by the UTC
D	Operators must not operate until approval is received

5. - E1D02

Which of the following may transmit special codes intended to obscure the meaning of messages?

Select	Answer
A	Data containing personal information
B	Binary control characters
C	Telecommand signals from a space telecommand station
D	Auxiliary relay links carrying repeater audio

6. - E1E10

What must the administering VEs do after the administration of a successful examination for an amateur operator license?

Select	Answer
A	They must collect and send the documents to the NCVEC for grading
B	They must submit the application document to the coordinating VEC according to the coordinating VEC instructions
C	They must collect and send the documents to the FCC according to instructions
D	They must collect and submit the documents to the coordinating VEC for grading

7. - E1F05

Amateur stations may not transmit in which of the following frequency segments if they are located in the contiguous 48 states and north of Line A?

Select	Answer
A	53 MHz - 54 MHz
B	420 MHz - 430 MHz
C	222 MHz - 223 MHz
D	440 MHz - 450 MHz

8. - E2A12

What is the purpose of digital store-and-forward functions on an amateur radio satellite?

Select	Answer
A	To store digital messages in the satellite for later download by other stations
B	To upload operational software for the transponder
C	To relay messages between satellites
D	To delay download of telemetry between satellites

9. - E2B08

What technique allows commercial analog TV receivers to be used for fast-scan TV operations on the 70 cm band?

Select	Answer
A	Using converted satellite TV dishes
B	Transmitting on channels shared with cable TV
C	Using USB and demodulating the signal with a computer sound card
D	Transmitting on the abandoned TV channel 2

10. - E2C12

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

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

11. - E2D01

Which of the following digital modes is designed for meteor scatter communications?

Select	Answer
A	Hellschreiber
B	WSPR
C	MSK144
D	APRS

12. - E2E02

What do the letters FEC mean as they relate to digital operation?

Select	Answer
A	Final Error Correction
B	Forward Error Correction
C	First Error Correction
D	Fatal Error Correction

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 F1 layer
B	The F2 layer
C	The E layer
D	The D layer

14. - E3B11

At what time of day can sporadic E propagation occur?

Select	Answer
A	Any time
B	Only around sunset and sunrise
C	Only in hours of darkness
D	Only around sunset

15. - E3C10

What does the 304A solar parameter measure?

Select	Answer
A	UV emissions at 304 angstroms, correlated to the solar flux index
B	The ratio of x-ray flux to radio flux, correlated to sunspot number
C	The solar wind velocity at 304 degrees from the solar equator, correlated to solar activity
D	The solar emission at 304 GHz, correlated to x-ray flare levels

16. - E4A07

Which of the following is an advantage of using an antenna analyzer compared to an SWR bridge to measure antenna SWR?

Select	Answer
A	Antenna analyzers do not need an external RF source
B	Antenna analyzers automatically tune your antenna for resonance
C	Antenna analyzers display a time-varying representation of the modulation envelope
D	All these choices are correct

17. - E4B07

What do the subscripts of S parameters represent?

Select	Answer
A	The relative time between measurements
B	Frequency order of the measurements
C	The port or ports at which measurements are made
D	Relative quality of the data

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	14.445 MHz
B	13.845 MHz
C	14.755 MHz
D	15.210 MHz

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

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 using a ground-fault current interrupter in the circuit used to power the motor
C	By installing a bypass capacitor in series with the motor leads
D	By installing a brute-force AC-line filter in series with the motor leads

21. - E5A02

What is resonance in an LC or RLC circuit?

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

22. - E5B05

What happens to the magnitude of a pure reactance when it is converted to a susceptance?

Select	Answer
A	It is shifted by 90 degrees
B	It is unchanged
C	It becomes the reciprocal
D	The sign is reversed

23. - E5C09

When using rectangular coordinates to graph the impedance of a circuit, what do the axes represent?

Select	Answer
A	The X axis represents the reactive component and the Y axis represents the resistive component
B	The X axis represents the phase angle and the Y axis represents the magnitude
C	The X axis represents the resistive component and the Y axis represents the reactive component
D	The X axis represents the magnitude and the Y axis represents the phase angle

24. - E5D07

How many watts are consumed in a circuit having a power factor of 0.71 if the apparent power is 500VA?

Select	Answer
A	355 W
B	1.42 mW
C	252 W
D	704 W

25. - E6A11

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

Select	Answer
A	2
B	6
C	1
D	3

26. - E6B10

In Figure E6-2, what is the schematic symbol for a light-emitting diode?

Select	Answer
A	7
B	6
C	1
D	5

27. - E6C04

Which of the following is an advantage of BiCMOS logic?

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

28. - E6D11

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

Select	Answer
A	Ferrite
B	Brass
C	Powdered iron
D	Ceramic

29. - E6E11

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

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

30. - E6F09

What is the efficiency of a photovoltaic cell?

Select	Answer
A	The open-circuit voltage divided by the short-circuit current under full illumination
B	Cost per kilowatt-hour generated
C	The output RF power divided by the input DC power
D	The relative fraction of light that is converted to current

31. - E7A06

What is a characteristic of a monostable multivibrator?

Select	Answer
A	It maintains a constant output voltage, regardless of variations in the input voltage
B	It stores one bit of data in either a 0 or 1 state
C	It produces a continuous square wave oscillating between 1 and 0
D	It switches momentarily to the opposite binary state and then returns to its original state after a set time

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	Switching amplifiers use push-pull circuits
C	Linear amplifiers have high gain resulting in higher harmonic content
D	Switching amplifiers operate at higher voltages

33. - E7C02

Which of the following is a property of a T-network with series capacitors and a parallel shunt inductor?

Select	Answer
A	It is a high-pass filter
B	It is a band-pass filter
C	It is a notch filter
D	It is a low-pass filter

34. - E7D11

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

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

35. - E7E08

What are the principal frequencies that appear at the output of a mixer circuit?

Select	Answer
A	1.414 and 0.707 times the input frequency
B	Two and four times the original frequency
C	The square root of the product of input frequencies
D	The two input frequencies along with their sum and difference frequencies

36. - E7F12

Which of the following is an advantage of a Finite Impulse Response (FIR) filter vs an Infinite Impulse Response (IIR) digital filter?

Select	Answer
A	FIR filters are easier to implement for a given set of passband rolloff requirements
B	FIR filters can delay all frequency components of the signal by the same amount
C	All these choices are correct
D	FIR filters can respond faster to impulses

37. - E7G01

What is the typical output impedance of an op-amp?

Select	Answer
A	Very low
B	Very high
C	100 ohms
D	1000 ohms

38. - E7H04

How is positive feedback supplied in a Colpitts oscillator?

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

39. - E8A11

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

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

40. - E8B10

What is frequency division multiplexing?

Select	Answer
A	The transmitted signal is divided into packets of information
B	Two or more information streams are merged into a digital combiner, which then pulse position modulates the transmitter
C	The transmitted signal jumps from band to band at a predetermined rate
D	Two or more information streams are merged into a baseband, which then modulates the transmitter

41. - E8C02

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

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

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 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 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

43. - E9A10

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

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

44. - E9B11

What is a disadvantage of decreasing the number of wire segments in an antenna model below 10 segments per half-wavelength?

Select	Answer
A	The antenna will become mechanically unstable
B	The resulting design will favor radiation of harmonic energy
C	Ground conductivity will not be accurately modeled
D	The computed feed point impedance may be incorrect

45. - E9C07

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

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

46. - E9D06

What happens to the SWR bandwidth when one or more loading coils are used to resonate an electrically short antenna?

Select	Answer
A	It is increased
B	It is unchanged if the loading coil is located at the feed point
C	It is unchanged if the loading coil is located at a voltage maximum point
D	It is decreased

47. - E9E04

What is the purpose of the series capacitor in a gamma-type antenna matching network?

Select	Answer
A	To transform the antenna impedance to a higher value
B	To provide a rejection notch that prevents the radiation of harmonics
C	To cancel the inductive reactance of the matching network
D	To provide DC isolation between the feed line and the antenna

48. - E9F07

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

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

49. - E9G07

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

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

50. - E9H08

What is the function of a sense antenna?

Select	Answer
A	It increases the sensitivity of a DF antenna array
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 allows DF antennas to receive signals at different vertical angles

Figure E6-1

Figure E6-2

Figure E9-3