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

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

3. - E1B07

To what type of regulations does PRB-1 apply?

Select	Answer
A	Homeowners associations
B	State and local zoning
C	FAA tower height limits
D	Use of wireless devices in vehicles

4. - E1C11

Which of the following operating arrangements allows an FCC-licensed U.S. citizen to operate in many European countries, and alien amateurs from many European countries to operate in the U.S.?

Select	Answer
A	CEPT agreement
B	All these choices are correct
C	ITU reciprocal license
D	IARP agreement

5. - E1D04

Which of the following is required in the identification transmissions from a balloon-borne telemetry station?

Select	Answer
A	All these choices are correct
B	Call sign
C	The station's six-character Maidenhead grid locator
D	The output power of the balloon transmitter

6. - E1E09

What may be the penalty for a VE who fraudulently administers or certifies an examination?

Select	Answer
A	All these choices are correct
B	A sentence of up to one year in prison
C	Revocation of the VE's amateur station license grant and the suspension of the VE's amateur operator license grant
D	A fine of up to $1000 per occurrence

7. - E1F03

Under what circumstances may a dealer sell an external RF power amplifier capable of operation below 144 MHz if it has not been granted FCC certification?

Select	Answer
A	It was purchased in used condition from an amateur operator and is sold to another amateur operator for use at that operator's station
B	The equipment dealer assembled it from a kit
C	It was imported from a manufacturer in a country that does not require certification of RF power amplifiers
D	It was imported from a manufacturer in another country and was certificated by that country's government

8. - E2A06

What are Keplerian elements?

Select	Answer
A	Parameters that define the orbit of a satellite
B	High-emission heater filaments used in magnetron tubes
C	Phase reversing elements in a Yagi antenna
D	Encrypting codes used for spread spectrum modulation

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

10. - E2C12

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

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

11. - E2D10

How can an APRS station be used to help support a public service communications activity?

Select	Answer
A	APRS stations with General Personnel Scanners can automatically relay the participant numbers and time as they pass the check points
B	An APRS station with an emergency medical technician can automatically transmit medical data to the nearest hospital
C	All these choices are correct
D	An APRS station with a Global Positioning System unit can automatically transmit information to show a mobile station's position during the event

12. - E2E12

How do ALE stations establish contact?

Select	Answer
A	ALE radios send a constant tone code to establish a frequency for future use
B	ALE radios activate when they hear their signal echoed by back scatter
C	ALE radios monitor an internet site for the frequency they are being paged on
D	ALE constantly scans a list of frequencies, activating the radio when the designated call sign is received

13. - E3A13

Which of these emission modes is best for auroral propagation?

Select	Answer
A	SSB
B	CW
C	FM
D	RTTY

14. - E3B02

What is the approximate maximum range for signals using transequatorial propagation?

Select	Answer
A	5000 miles
B	7500 miles
C	2500 miles
D	1000 miles

15. - E3C14

Why does the radio-path horizon distance exceed the geometric horizon?

Select	Answer
A	Due to the Doppler effect
B	E-region skip
C	Downward bending due to density variations in the atmosphere
D	D-region skip

16. - E4A10

Which of the following displays multiple digital signal states simultaneously?

Select	Answer
A	Logic analyzer
B	Network analyzer
C	Modulation monitor
D	Bit error rate tester

17. - E4B05

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

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

18. - E4C07

What does the MDS of a receiver represent?

Select	Answer
A	The multiplex distortion stability
B	The maximum detectable spectrum
C	The meter display sensitivity
D	The minimum discernible signal

19. - E4D02

Which of the following describes problems caused by poor dynamic range in a receiver?

Select	Answer
A	Oscillator instability and severe audio distortion of all but the strongest received signals
B	Cross-modulation of the desired signal and insufficient audio power to operate the speaker
C	Oscillator instability requiring frequent retuning and loss of ability to recover the opposite sideband
D	Spurious signals caused by cross-modulation and desensitization from strong adjacent signals

20. - E4E03

Which of the following signals might a receiver noise blanker be able to remove from desired signals?

Select	Answer
A	Signals that are constant at all IF levels
B	Signals that appear at one IF but not another
C	Signals that appear across a wide bandwidth
D	Signals that have a sharply peaked frequency distribution

21. - E5A02

What is resonance in an LC or RLC circuit?

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

22. - E5B09

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

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

23. - E5C05

What is the name of the diagram used to show the phase relationship between impedances at a given frequency?

Select	Answer
A	Far field diagram
B	Near field diagram
C	Phasor diagram
D	Venn diagram

24. - E5D15

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

Select	Answer
A	0.5
B	0.707
C	1.0
D	0.866

25. - E6A07

Which of the following indicates that a silicon NPN junction transistor is biased on?

Select	Answer
A	Base-to-emitter voltage of approximately 6 to 7 volts
B	Base-to-emitter resistance of approximately 0.6 to 0.7 ohms
C	Base-to-emitter resistance of approximately 6 to 7 ohms
D	Base-to-emitter voltage of approximately 0.6 to 0.7 volts

26. - E6B08

Which of the following is a Schottky barrier diode?

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

27. - 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

28. - E6D10

What is a primary advantage of using a toroidal core instead of a solenoidal core in an inductor?

Select	Answer
A	Toroidal cores confine most of the magnetic field within the core material
B	Toroidal cores have lower Q characteristics
C	Toroidal cores exhibit greater hysteresis
D	Toroidal cores make it easier to couple the magnetic energy into other components

29. - E6E05

Which of the following noise figure values is typical of a low-noise UHF preamplifier?

Select	Answer
A	-10 dB
B	-20 dBm
C	2 dB
D	44 dBm

30. - E6F04

What is the photovoltaic effect?

Select	Answer
A	The conversion of voltage to current when exposed to light
B	The conversion of electrical energy to mechanical energy
C	The tendency of a battery to discharge when exposed to light
D	The conversion of light to electrical energy

31. - E7A03

Which of the following can divide the frequency of a pulse train by 2?

Select	Answer
A	A multiplexer
B	A flip-flop
C	An OR gate
D	An XOR gate

32. - E7B06

Which of the following amplifier types reduces even-order harmonics?

Select	Answer
A	Class AB
B	Class C
C	Push-push
D	Push-pull

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

34. - E7D12

What is the dropout voltage of an analog voltage regulator?

Select	Answer
A	Minimum input voltage for rated power dissipation
B	Maximum output voltage drops when the input voltage is varied over its specified range
C	Maximum that the output voltage may decrease at rated load
D	Minimum input-to-output voltage required to maintain regulation

35. - E7E05

What circuit is added to an FM transmitter to boost the higher audio frequencies?

Select	Answer
A	A heterodyne suppressor
B	A pre-emphasis network
C	A de-emphasis network
D	A heterodyne enhancer

36. - E7F07

What function is performed by a Fast Fourier Transform?

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

37. - E7G08

How does the gain of an ideal operational amplifier vary with frequency?

Select	Answer
A	It increases linearly with increasing frequency
B	It decreases linearly with increasing frequency
C	It does not vary with frequency
D	It decreases logarithmically with increasing frequency

38. - E7H02

What is a microphonic?

Select	Answer
A	Changes in oscillator frequency due to mechanical vibration
B	Excess loading of the microphone by an oscillator
C	Distortion caused by RF pickup on the microphone cable
D	An IC used for amplifying microphone signals

39. - E8A08

Why would a direct or flash conversion analog-to-digital converter be useful for a software defined radio?

Select	Answer
A	Immunity to out-of-sequence coding reduces spurious responses
B	Very high speed allows digitizing high frequencies
C	All these choices are correct
D	Very low power consumption decreases frequency drift

40. - E8B05

What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus-or-minus 5 kHz when the maximum modulation frequency is 3 kHz?

Select	Answer
A	1.67
B	0.6
C	60
D	0.167

41. - E8C01

How is Forward Error Correction implemented?

Select	Answer
A	By the receiving station repeating each block of three data characters
B	By varying the frequency shift of the transmitted signal according to a predefined algorithm
C	By transmitting a special algorithm to the receiving station along with the data characters
D	By transmitting extra data that may be used to detect and correct transmission errors

42. - E8D03

How does the spread spectrum technique of frequency hopping work?

Select	Answer
A	A binary bit stream is used to shift the phase of an RF carrier very rapidly in a pseudorandom sequence
B	The frequency of the transmitted signal is changed very rapidly according to a pseudorandom sequence also used by the receiving station
C	If interference is detected by the receiver it will signal the transmitter to wait until the frequency is clear
D	If interference is detected by the receiver it will signal the transmitter to change frequencies

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	2.79 dB
B	6.0 dB
C	8.15 dB
D	3.85 dB

44. - E9B06

What is the elevation angle of peak response in the antenna radiation pattern shown in Figure E9-2?

Select	Answer
A	25 degrees
B	45 degrees
C	7.5 degrees
D	75 degrees

45. - E9C08

What is a folded dipole antenna?

Select	Answer
A	A dipole one-quarter wavelength long
B	A type of ground-plane antenna
C	A dipole configured to provide forward gain
D	A half-wave dipole with an additional parallel wire connecting its two ends

46. - E9D03

Where should a high Q loading coil be placed to minimize losses in a shortened vertical antenna?

Select	Answer
A	At a voltage node
B	As close to the transmitter as possible
C	As low as possible on the vertical radiator
D	Near the center of the vertical radiator

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 gamma match
D	The delta match

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 loss
C	Lower velocity factor
D	Higher SWR

49. - E9G05

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

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

50. - E9H10

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

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

Figure E9-2