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

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1. - E0A08

What does SAR measure?

SelectAnswer
AThe rate of RF energy reflected from stationary terrain
BSignal Amplification Rating
CThe rate at which RF energy is absorbed by the body
DSynthetic Aperture Ratio of the human body

2. - E1A04

With your transceiver displaying the carrier frequency of phone signals, you hear a DX station calling CQ on 3.601 MHz LSB. Is it legal to return the call using lower sideband on the same frequency?

SelectAnswer
AYes, because the DX station initiated the contact
BYes, because the displayed frequency is within the 75 meter phone band segment
CNo, the sideband will extend beyond the edge of the phone band segment
DNo, U.S. stations are not permitted to use phone emissions below 3.610 MHz

3. - E1B01

Which of the following constitutes a spurious emission?

SelectAnswer
AA signal transmitted to prevent its detection by any station other than the intended recipient
BAn amateur station transmission made without the proper call sign identification
CAny transmitted signal that unintentionally interferes with another licensed radio station
DAn emission outside the signal's necessary bandwidth that can be reduced or eliminated without affecting the information transmitted

4. - E1C08

What is the maximum permissible duration of a remotely controlled station's transmissions if its control link malfunctions?

SelectAnswer
A3 minutes
B30 seconds
C10 minutes
D5 minutes

5. - E1D05

What must be posted at the station location of a station being operated by telecommand on or within 50 km of the earth's surface?

SelectAnswer
AA photocopy of the station license
BAll these choices are correct
CA label with the name, address, and telephone number of the station licensee
DA label with the name, address, and telephone number of the control operator

6. - E1E04

Which of the following best describes the Volunteer Examiner accreditation process?

SelectAnswer
AThe amateur operator applying must pass a VE examination administered by the FCC Enforcement Bureau
BThe prospective VE obtains accreditation from the FCC
CThe procedure by which a VEC confirms that the VE applicant meets FCC requirements to serve as an examiner
DEach General, Advanced and Amateur Extra Class operator is automatically accredited as a VE when the license is granted

7. - E1F09

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

SelectAnswer
AA station transmitting SS emission must not cause harmful interference to other stations employing other authorized emissions
BAll these choices are correct
CThe transmitting station must be in an area regulated by the FCC or in a country that permits SS emissions
DThe transmission must not be used to obscure the meaning of any communication

8. - E2A04

What is meant by the term mode? as applied to an amateur radio satellite?

SelectAnswer
AThe satellite's uplink and downlink frequency bands
BThe satellite's orientation with respect to the Earth
CWhether the satellite is in a polar or equatorial orbit
DWhether the satellite is in a low earth or geostationary orbit

9. - E2B02

How many horizontal lines make up a fast-scan (NTSC) television frame?

SelectAnswer
A30
B525
C60
D1080

10. - E2C07

What is the Cabrillo format?

SelectAnswer
AThe rules of order for meetings between contest sponsors
BA method of exchanging information during a contest QSO
CThe most common set of contest rules
DA standard for submission of electronic contest logs

11. - E2D05

What is one advantage of the JT65 mode?

SelectAnswer
AThe ability to decode signals which have a very low signal-to-noise ratio
BPermits fast-scan TV transmissions over narrow bandwidth
CUses only a 65 Hz bandwidth
DEasily copied by ear if necessary

12. - E2E09

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

SelectAnswer
ARTTY
BPACTOR
CPSK31
DMT63

13. - E3A13

Which of these emission modes is best for auroral propagation?

SelectAnswer
ASSB
BFM
CCW
DRTTY

14. - E3B07

What happens to linearly polarized radio waves that split into ordinary and extraordinary waves in the ionosphere?

SelectAnswer
AThey become elliptically polarized
BThey are bent toward the magnetic poles
CThey become phase locked
DThey become depolarized

15. - E3C05

What orientation of Bz (B sub z) increases the likelihood that incoming particles from the sun will cause disturbed conditions?

SelectAnswer
ANorthward
BWestward
CEastward
DSouthward

16. - E4A07

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

SelectAnswer
AAntenna analyzers display a time-varying representation of the modulation envelope
BAntenna analyzers do not need an external RF source
CAll these choices are correct
DAntenna analyzers automatically tune your antenna for resonance

17. - E4B09

What is indicated if the current reading on an RF ammeter placed in series with the antenna feed line of a transmitter increases as the transmitter is tuned to resonance?

SelectAnswer
AThere is more power going into the antenna
BThe transmitter is not properly neutralized
CThere is possibly a short to ground in the feed line
DThere is an impedance mismatch between the antenna and feed line

18. - E4C08

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

SelectAnswer
AOne-half the maximum sample rate
BOne-half the maximum sampling buffer size
CThe reference voltage of the analog-to-digital converter
DThe maximum count value of the analog-to-digital converter

19. - E4D09

What is the purpose of the preselector in a communications receiver?

SelectAnswer
ATo provide a range of AGC time constants
BTo allow selection of the optimum RF amplifier device
CTo increase rejection of signals outside the desired band
DTo store often-used frequencies

20. - E4E11

What could cause local AM broadcast band signals to combine to generate spurious signals in the MF or HF bands?

SelectAnswer
ANearby corroded metal joints are mixing and re-radiating the broadcast signals
BYou are receiving skywave signals from a distant station
CYour station receiver IF amplifier stage is defective
DOne or more of the broadcast stations is transmitting an over-modulated signal

21. - E5A03

What is the magnitude of the impedance of a series RLC circuit at resonance?

SelectAnswer
AApproximately equal to inductive reactance
BHigh, as compared to the circuit resistance
CApproximately equal to capacitive reactance
DApproximately equal to circuit resistance

22. - E5B05

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

SelectAnswer
AIt is shifted by 90 degrees
BThe sign is reversed
CIt is unchanged
DIt becomes the reciprocal

23. - E5C04

What coordinate system is often used to display the resistive, inductive, and/or capacitive reactance components of impedance?

SelectAnswer
AFaraday grid
BElliptical coordinates
CMaidenhead grid
DRectangular coordinates

24. - E5D06

In what direction is the magnetic field oriented about a conductor in relation to the direction of electron flow?

SelectAnswer
AIn all directions; omni-directional
BIn the same direction as the current
CIn a circle around the conductor
DIn a direction opposite to the current

25. - E6A10

In Figure E6-1, what is the schematic symbol for an N-channel dual-gate MOSFET?

SelectAnswer
A2
B5
C4
D6

26. - E6B02

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

SelectAnswer
ALess forward voltage drop
BMuch higher reverse voltage breakdown
CMore constant reverse avalanche voltage
DLonger carrier retention time

27. - E6C11

In Figure E6-3, what is the schematic symbol for the NOT operation (inverter)?

SelectAnswer
A6
B4
C5
D2

28. - E6D04

Which materials are commonly used as a core in an inductor?

SelectAnswer
ATeflon and Delrin
BFerrite and brass
CPolystyrene and polyethylene
DCobalt and aluminum

29. - E6E04

Which is the most common input and output impedance of circuits that use MMICs?

SelectAnswer
A300 ohms
B50 ohms
C450 ohms
D10 ohms

30. - E6F10

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

SelectAnswer
ACadmium Sulfide
BSilicon
CSelenium
DCopper oxide

31. - E7A09

What logical operation is performed by an exclusive NOR gate?

SelectAnswer
AIt produces logic 0 at its output only if all inputs are logic 0
BIt produces logic 0 at its output if only one input is logic 1
CIt produces logic 1 at its output only if all inputs are logic 1
DIt produces logic 1 at its output if only one input is logic 1

32. - E7B11

In Figure E7-1, what is the purpose of R3?

SelectAnswer
AOutput load resistor
BFixed bias
CSelf bias
DEmitter bypass

33. - E7C08

Which of the following factors has the greatest effect on the bandwidth and response shape of a crystal ladder filter?

SelectAnswer
AThe gain of the RF stage preceding the filter
BThe amplitude of the signals passing through the filter
CThe relative frequencies of the individual crystals
DThe DC voltage applied to the quartz crystal

34. - E7D11

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

SelectAnswer
AMaintains nearly constant output voltage over a wide range of load current
BPermits a wide range of output voltage settings
CProvides a stable input impedance over a wide range of source voltage
DMaintains nearly constant output impedance over a wide range of load current

35. - E7E01

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

SelectAnswer
AA balanced modulator on the audio amplifier
BA balanced modulator on the oscillator
CA reactance modulator on the final amplifier
DA reactance modulator on the oscillator

36. - E7F04

What is a common method of generating an SSB signal using digital signal processing?

SelectAnswer
AMixing products are converted to voltages and subtracted by adder circuits
BA frequency synthesizer removes the unwanted sidebands
CVarying quartz crystal characteristics emulated in digital form
DSignals are combined in quadrature phase relationship

37. - E7G04

What is meant by the "op-amp input offset voltage"?

SelectAnswer
AThe potential between the amplifier input terminals of the op-amp in an open loop condition
BThe difference between the output voltage of the op-amp and the input voltage required in the immediately following stage
CThe differential input voltage needed to bring the open loop output voltage to zero
DThe output voltage of the op-amp minus its input voltage

38. - E7H01

What are three oscillator circuits used in amateur radio equipment?

SelectAnswer
ATaft, Pierce and negative feedback
BColpitts, Hartley and Pierce
CTaft, Hartley and Pierce
DPierce, Fenner and Beane

39. - E8A01

What is the name of the process that shows that a square wave is made up of a sine wave plus all its odd harmonics?

SelectAnswer
AVector analysis
BNumerical analysis
CFourier analysis
DDifferential analysis

40. - E8B07

Orthogonal Frequency Division Multiplexing is a technique used for which type of amateur communication?

SelectAnswer
AEME
BHigh-speed digital modes
CExtremely low-power contacts
DOFDM signals are not allowed on amateur bands

41. - E8C07

What is the bandwidth of a 4800-Hz frequency shift, 9600-baud ASCII FM transmission?

SelectAnswer
A5.76 kHz
B4.8 kHz
C9.6 kHz
D15.36 kHz

42. - E8D04

What is the primary effect of extremely short rise or fall time on a CW signal?

SelectAnswer
AThe generation of RF harmonics
BLimits data speed
CThe generation of key clicks
DMore difficult to copy

43. - E9A07

What is the effective isotropic radiated power of a repeater station with 200 watts transmitter power output, 2 dB feed line loss, 2.8 dB duplexer loss, 1.2 dB circulator loss, and 7 dBi antenna gain?

SelectAnswer
A159 watts
B632 watts
C252 watts
D63.2 watts

44. - E9B09

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

SelectAnswer
AMethod of Moments
BMutual impedance analysis
CGraphical analysis
DCalculus differentiation with respect to physical properties

45. - E9C04

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

SelectAnswer
AThe lobes align more in the direction of the wire
BThe front-to-back ratio decreases
CThe lobes become more perpendicular to the wire
DThe vertical angle increases

46. - E9D04

Why should an HF mobile antenna loading coil have a high ratio of reactance to resistance?

SelectAnswer
ATo lower the radiation angle
BTo swamp out harmonics
CTo minimize the Q
DTo minimize losses

47. - 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?

SelectAnswer
AThe stub matching system
BThe omega matching system
CThe gamma matching system
DThe delta matching system

48. - E9F01

What is the velocity factor of a transmission line?

SelectAnswer
AThe index of shielding for coaxial cable
BThe ratio of the characteristic impedance of the line to the terminating impedance
CThe velocity of the wave in the transmission line multiplied by the velocity of light in a vacuum
DThe velocity of the wave in the transmission line divided by the velocity of light in a vacuum

49. - E9G07

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

SelectAnswer
AThe voltage axis
BThe resistance axis
CThe reactance axis
DThe current axis

50. - E9H10

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

SelectAnswer
ABy utilizing high impedance wire for the coupling loop
BBy reducing the permeability of the loop shield
CBy increasing the number of turns and/or the area
DBy winding adjacent turns in opposing directions

Figure E6-1

Figure E6-3

Figure E7-1

Figure E9-3