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

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1. - E0A02

When evaluating RF exposure levels from your station at a neighbor's home, what must you do?

Select	Answer
A	Ensure signals from your station are less than the controlled Maximum Permitted Emission (MPE) limits
B	Ensure signals from your station are less than the uncontrolled Maximum Permitted Emission (MPE) limits
C	Ensure signals from your station are less than the controlled Maximum Permitted Exposure (MPE) limits
D	Ensure signals from your station are less than the uncontrolled Maximum Permitted Exposure (MPE) limits

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

3. - E1B10

What frequencies are authorized to an amateur station operating under RACES rules?

Select	Answer
A	Military Auxiliary Radio System (MARS) channels
B	All amateur service frequencies authorized to the control operator
C	Specific segments in the amateur service MF, HF, VHF and UHF bands
D	Specific local government channels

4. - E1C09

What is the highest modulation index permitted at the highest modulation frequency for angle modulation below 29.0 MHz?

Select	Answer
A	2.0
B	3.0
C	1.0
D	0.5

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	The output power of the balloon transmitter
C	Call sign
D	The station's six-character Maidenhead grid locator

6. - E1E06

Who is responsible for the proper conduct and necessary supervision during an amateur operator license examination session?

Select	Answer
A	The VEC coordinating the session
B	The VE session manager
C	Each administering VE
D	The FCC

7. - E1F09

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

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

8. - E2A08

Why should effective radiated power to a satellite that uses a linear transponder be limited?

Select	Answer
A	To avoid reducing the downlink power to all other users
B	To avoid interfering with terrestrial QSOs
C	To prevent the satellite from emitting out-of-band signals
D	To prevent creating errors in the satellite telemetry

9. - E2B01

How many times per second is a new frame transmitted in a fast-scan (NTSC) television system?

Select	Answer
A	60
B	90
C	30
D	120

10. - E2C07

What is the Cabrillo format?

Select	Answer
A	A standard for submission of electronic contest logs
B	The rules of order for meetings between contest sponsors
C	The most common set of contest rules
D	A method of exchanging information during a contest QSO

11. - E2D01

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

Select	Answer
A	WSPR
B	MSK144
C	APRS
D	Hellschreiber

12. - E2E03

How is the timing of FT4 contacts organized?

Select	Answer
A	By exchanging ACK/NAK packets
B	It depends on the lunar phase
C	Stations take turns on alternate days
D	Alternating transmissions at 7.5 second intervals

13. - E3A06

What might help to restore contact when DX signals become too weak to copy across an entire HF band a few hours after sunset?

Select	Answer
A	Switch to a lower frequency HF band
B	Wait 24 hours before attempting another communication on the band
C	Wait 90 minutes or so for the signal degradation to pass
D	Switch to a higher frequency HF band

14. - E3B01

What is transequatorial propagation?

Select	Answer
A	Propagation between points located on the magnetic equator
B	Propagation between a point on the equator and its antipodal point
C	Propagation between points at the same latitude
D	Propagation between two mid-latitude points at approximately the same distance north and south of the magnetic equator

15. - E3C04

What does the value of Bz (B sub Z) represent?

Select	Answer
A	Duration of long-delayed echoes
B	Direction and strength of the interplanetary magnetic field
C	Critical frequency for vertical transmissions
D	Geomagnetic field stability

16. - E4A08

Which of the following measures SWR?

Select	Answer
A	A spectrum analyzer
B	An ohmmeter
C	A Q meter
D	An antenna analyzer

17. - E4B03

Which S parameter is equivalent to forward gain?

Select	Answer
A	S11
B	S12
C	S21
D	S22

18. - E4C02

Which of the following receiver circuits can be effective in eliminating interference from strong out-of-band signals?

Select	Answer
A	A front-end filter or pre-selector
B	A narrow IF filter
C	A notch filter
D	A properly adjusted product detector

19. - E4D06

What is the term for spurious signals generated by the combination of two or more signals in a non-linear device or circuit?

Select	Answer
A	Intermodulation
B	Neutralization
C	Adjacent channel interference
D	Amplifier desensitization

20. - E4E05

How can radio frequency interference from an AC motor be suppressed?

Select	Answer
A	By installing a brute-force AC-line filter in series with the motor leads
B	By using a ground-fault current interrupter in the circuit used to power the motor
C	By installing a high-pass filter in series with the motor's power leads
D	By installing a bypass capacitor in series with the motor leads

21. - E5A13

What is an effect of increasing Q in a series resonant circuit?

Select	Answer
A	Phase shift can become uncontrolled
B	Internal voltages increase
C	Parasitic effects are minimized
D	Fewer components are needed for the same performance

22. - E5B12

What is admittance?

Select	Answer
A	The inverse of impedance
B	The term for the gain of a field effect transistor
C	The turns ratio of a transformer
D	The inverse of Q factor

23. - E5C12

Which point on Figure E5-1 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 3
C	Point 8
D	Point 7

24. - E5D09

What happens to reactive power in an AC circuit that has both ideal inductors and ideal capacitors?

Select	Answer
A	It is dissipated in the formation of inductive and capacitive fields
B	It is dissipated as kinetic energy in the circuit
C	It is dissipated as heat in the circuit
D	It is repeatedly exchanged between the associated magnetic and electric fields, but is not dissipated

25. - E6A02

Which of the following semiconductor materials contains excess free electrons?

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

26. - E6B03

What type of bias is required for an LED to emit light?

Select	Answer
A	Reverse bias
B	Forward bias
C	Inductive bias
D	Zero bias

27. - E6C03

What is tri-state logic?

Select	Answer
A	Logic devices with 0, 1, and high-impedance output states
B	Low-power logic devices designed to operate at 3 volts
C	Logic devices that utilize ternary math
D	Proprietary logic devices manufactured by Tri-State Devices

28. - E6D11

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

Select	Answer
A	Ferrite
B	Ceramic
C	Brass
D	Powdered iron

29. - E6E01

Why is gallium arsenide (GaAs) useful for semiconductor devices operating at UHF and higher frequencies?

Select	Answer
A	Lower transconductance
B	Higher electron mobility
C	Higher noise figures
D	Lower junction voltage drop

30. - E6F03

What is the most common configuration of an optoisolator or optocoupler?

Select	Answer
A	An LED and a phototransistor
B	A frequency modulated helium-neon laser
C	A lens and a photomultiplier
D	An amplitude modulated helium-neon laser

31. - E7A10

What is a truth table?

Select	Answer
A	A table of logic symbols that indicate the high logic states of an op-amp
B	A list of inputs and corresponding outputs for a digital device
C	A table of logic symbols that indicate the logic states of an op-amp
D	A diagram showing logic states when the digital device output is true

32. - E7B07

Which of the following is a likely result when a Class C amplifier is used to amplify a single-sideband phone signal?

Select	Answer
A	Increased overall intelligibility
B	Signal inversion
C	Reduced intermodulation products
D	Signal distortion and excessive bandwidth

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

34. - E7D03

What device is typically used as a stable voltage reference in a linear voltage regulator?

Select	Answer
A	A Zener diode
B	A tunnel diode
C	An SCR
D	A varactor diode

35. - E7E10

How does a diode envelope detector function?

Select	Answer
A	By sensing the change of reactance in the diode with respect to frequency
B	By breakdown of the Zener voltage
C	By mixing signals with noise in the transition region of the diode
D	By rectification and filtering of RF signals

36. - E7F13

What is the function of taps in a digital signal processing filter?

Select	Answer
A	Select the point at which baseband signals are generated
B	To reduce excess signal pressure levels
C	Provide incremental signal delays for filter algorithms
D	Provide access for debugging software

37. - E7G05

How can unwanted ringing and audio instability be prevented in an op-amp RC audio filter circuit?

Select	Answer
A	Restrict gain but increase Q
B	Restrict both gain and Q
C	Increase both gain and Q
D	Restrict Q but increase gain

38. - E7H03

How is positive feedback supplied in a Hartley oscillator?

Select	Answer
A	Through a capacitive divider
B	Through a neutralizing capacitor
C	Through a tapped coil
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	Reciprocal mixing
C	Total harmonic distortion
D	Power factor

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	Two or more information streams are merged into a baseband, which then modulates the transmitter
D	The transmitted signal jumps from band to band at a predetermined rate

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 rate at which the waveform changes to convey information
C	The duration of each bit in a message sent over the air
D	The number of control characters in a message packet

42. - E8D03

How does the spread spectrum technique of frequency hopping work?

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

43. - E9A02

What is the effective radiated power relative to a dipole of a repeater station with 150 watts transmitter power output, 2 dB feed line loss, 2.2 dB duplexer loss, and 7 dBd antenna gain?

Select	Answer
A	286 watts
B	78.7 watts
C	1977 watts
D	420 watts

44. - E9B06

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

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

45. - E9C04

What happens to the radiation pattern of an unterminated long wire antenna as the wire length is increased?

Select	Answer
A	The front-to-back ratio decreases
B	The lobes become more perpendicular to the wire
C	The vertical angle increases
D	The lobes align more in the direction of the wire

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

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. - E9F08

Which of the following is a significant difference between foam dielectric coaxial cable and solid dielectric cable, assuming all other parameters are the same?

Select	Answer
A	All these choices are correct
B	Foam dielectric has lower safe operating voltage limits
C	Foam dielectric has lower loss per unit of length
D	Foam dielectric has higher velocity factor

49. - E9G02

What type of coordinate system is used in a Smith chart?

Select	Answer
A	Voltage lines and current chords
B	Resistance circles and reactance arcs
C	Voltage circles and current arcs
D	Resistance lines and reactance chords

50. - E9H04

What is an advantage of placing a grounded electrostatic shield around a small loop direction-finding antenna?

Select	Answer
A	It eliminates tracking errors caused by strong out-of-band signals
B	It increases signal strength by providing a better match to the feed line
C	It eliminates unbalanced capacitive coupling to the surroundings, improving the nulls
D	It adds capacitive loading, increasing the bandwidth of the antenna

Figure E5-1

Figure E9-2