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

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1. - E0A03

Over what range of frequencies are the FCC human body RF exposure limits most restrictive?

SelectAnswer
A300 kHz to 3 MHz
B3 to 30 MHz
C30 to 300 MHz
D300 to 3000 MHz

2. - E1A10

If an amateur station is installed aboard a ship or aircraft, what condition must be met before the station is operated?

SelectAnswer
AThe amateur operator must have an FCC Marine or Aircraft endorsement on his or her amateur license
BThe amateur station operator must agree not to transmit when the main radio of the ship or aircraft is in use
CIts operation must be approved by the master of the ship or the pilot in command of the aircraft
DThe amateur station must have a power supply that is completely independent of the main ship or aircraft power supply

3. - 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?

SelectAnswer
AThe amateur station must cease operation on all frequencies above 30 MHz
BThe amateur station must avoid transmitting during certain hours on frequencies that cause the interference
CThe amateur station must cease operation on all frequencies below 30 MHz
DThe amateur station must cease operation

4. - E1C01

What is the maximum bandwidth for a data emission on 60 meters?

SelectAnswer
A170 Hz
B1.5 kHz
C60 Hz
D2.8 kHz

5. - E1D04

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

SelectAnswer
AThe output power of the balloon transmitter
BThe station's six-character Maidenhead grid locator
CCall sign
DAll these choices are correct

6. - E1E06

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

SelectAnswer
AThe VEC coordinating the session
BEach administering VE
CThe FCC
DThe VE session manager

7. - E1F09

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

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

8. - E2A10

What type of satellite appears to stay in one position in the sky?

SelectAnswer
AHEO
BLEO
CGeostationary
DGeomagnetic

9. - E2B04

How is color information sent in analog SSTV?

SelectAnswer
AColor lines are sent sequentially
BColor is amplitude modulated on the frequency modulated intensity signal
CColor information is sent on a 2.8 kHz subcarrier
DColor is sent in a color burst at the end of each line

10. - E2C11

How should you generally identify your station when attempting to contact a DX station during a contest or in a pileup?

SelectAnswer
ASend your full call sign once or twice
BSend the call sign of the DX station three times, the words this is,then your call sign three times
CSend your full call sign and grid square
DSend only the last two letters of your call sign until you make contact

11. - E2D05

What is one advantage of the JT65 mode?

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

12. - E2E05

Which of these digital modes does not support keyboard-to-keyboard operation?

SelectAnswer
APSK31
BPACTOR
CMFSK
DRTTY

13. - E3A14

What is meant by circularly polarized electromagnetic waves?

SelectAnswer
AWaves produced by a loop antenna
BWaves with an electric field bent into a circular shape
CWaves with a rotating electric field
DWaves that circle the Earth

14. - E3B05

Which amateur bands typically support long-path propagation?

SelectAnswer
A6 meters to 2 meters
BOnly 160 meters to 40 meters
C160 meters to 10 meters
DOnly 30 meters to 10 meters

15. - E3C01

What does the radio communication term "ray tracing" describe?

SelectAnswer
AModeling a radio wave's path through the ionosphere
BDetermining the radiation pattern from an array of antennas
CThe process in which an electronic display presents a pattern
DEvaluating high voltage sources for x-rays

16. - E4A09

Which of the following is good practice when using an oscilloscope probe?

SelectAnswer
AKeep the signal ground connection of the probe as short as possible
BNever use a DC-coupled probe to measure an AC circuit
CNever use a high-impedance probe to measure a low-impedance circuit
DAll these choices are correct

17. - E4B08

Which of the following can be used to measure the Q of a series-tuned circuit?

SelectAnswer
AThe frequency shift
BThe inductance to capacitance ratio
CThe bandwidth of the circuit's frequency response
DThe resonant frequency of the circuit

18. - E4C09

Which of the following choices is a good reason for selecting a high frequency for the design of the IF in a superheterodyne HF or VHF communications receiver?

SelectAnswer
AImproved receiver noise figure
BEasier for front-end circuitry to eliminate image responses
CFewer components in the receiver
DReduced drift

19. - E4D10

What does a third-order intercept level of 40 dBm mean with respect to receiver performance?

SelectAnswer
AA pair of 40 dBm input signals will theoretically generate a third-order intermodulation product that has the same output amplitude as either of the input signals
BSignals less than 40 dBm will not generate audible third-order intermodulation products
CThe receiver can tolerate signals up to 40 dB above the noise floor without producing third-order intermodulation products
DA pair of 1 mW input signals will produce a third-order intermodulation product that is 40 dB stronger than the input signal

20. - E4E06

What is one type of electrical interference that might be caused by a nearby personal computer?

SelectAnswer
AA clicking noise at intervals of a few seconds
BThe appearance of unstable modulated or unmodulated signals at specific frequencies
CA loud AC hum in the audio output of your station receiver
DA whining type noise that continually pulses off and on

21. - E5A11

What is the half-power bandwidth of a resonant circuit that has a resonant frequency of 7.1 MHz and a Q of 150?

SelectAnswer
A157.8 Hz
B315.6 Hz
C47.3 kHz
D23.67 kHz

22. - E5B09

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

SelectAnswer
AVoltage and current are 180 degrees out of phase
BCurrent leads voltage by 90 degrees
CVoltage leads current by 90 degrees
DVoltage and current are in phase

23. - E5C11

Which point in Figure E5-1 best represents the impedance of a series circuit consisting of a 300-ohm resistor and an 18-microhenry inductor at 3.505 MHz?

SelectAnswer
APoint 7
BPoint 8
CPoint 3
DPoint 1

24. - E5D11

What is the power factor of an RL circuit having a 60-degree phase angle between the voltage and the current?

SelectAnswer
A0.866
B1.414
C0.5
D1.73

25. - E6A07

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

SelectAnswer
ABase-to-emitter resistance of approximately 0.6 to 0.7 ohms
BBase-to-emitter resistance of approximately 6 to 7 ohms
CBase-to-emitter voltage of approximately 0.6 to 0.7 volts
DBase-to-emitter voltage of approximately 6 to 7 volts

26. - E6B07

What is the failure mechanism when a junction diode fails due to excessive current?

SelectAnswer
AExcessive junction temperature
BInsufficient forward voltage
CCharge carrier depletion
DExcessive inverse voltage

27. - E6C06

Why do CMOS digital integrated circuits have high immunity to noise on the input signal or power supply?

SelectAnswer
AThe input switching threshold is about two times the power supply voltage
BThe input switching threshold is about one-half the power supply voltage
CBandwidth is very limited
DLarge bypass capacitance is inherent

28. - E6D11

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

SelectAnswer
AFerrite
BBrass
CPowdered iron
DCeramic

29. - E6E07

What type of transmission line is used for connections to MMICs?

SelectAnswer
AMiniature coax
BMicrostrip
CParallel wire
DCircular waveguide

30. - E6F07

What is a solid-state relay?

SelectAnswer
AA relay using transistors to drive the relay coil
BA mechanical relay that latches in the on or off state each time it is pulsed
CA semiconductor passive delay line
DA device that uses semiconductors to implement the functions of an electromechanical relay

31. - E7A06

What is a characteristic of a monostable multivibrator?

SelectAnswer
AIt produces a continuous square wave oscillating between 1 and 0
BIt switches momentarily to the opposite binary state and then returns to its original state after a set time
CIt stores one bit of data in either a 0 or 1 state
DIt maintains a constant output voltage, regardless of variations in the input voltage

32. - E7B14

Why are switching amplifiers more efficient than linear amplifiers?

SelectAnswer
ASwitching amplifiers use push-pull circuits
BSwitching amplifiers operate at higher voltages
CThe power transistor is at saturation or cutoff most of the time
DLinear amplifiers have high gain resulting in higher harmonic content

33. - E7C03

What advantage does a series-L Pi-L-network have over a series-L Pi-network for impedance matching between the final amplifier of a vacuum-tube transmitter and an antenna?

SelectAnswer
AGreater harmonic suppression
BHigher efficiency
CDoes not require a capacitor
DGreater transformation range

34. - E7D08

What type of circuit is shown in Figure E7-2?

SelectAnswer
ALinear voltage regulator
BMonostable multivibrator
CGrounded emitter amplifier
DSwitching voltage regulator

35. - E7E03

What is a frequency discriminator stage in a FM receiver?

SelectAnswer
AAn automatic band-switching circuit
BA circuit for filtering two closely adjacent signals
CA circuit for detecting FM signals
DAn FM generator circuit

36. - E7F11

What sets the minimum detectable signal level for a direct-sampling SDR receiver in the absence of atmospheric or thermal noise?

SelectAnswer
AReference voltage level and sample width in bits
BData storage transfer rate
CSample clock phase noise
DMissing codes and jitter

37. - E7G02

What is ringing in a filter?

SelectAnswer
AAn echo caused by a long time delay
BPartial cancellation of the signal over a range of frequencies
CA reduction in high frequency response
DUndesired oscillations added to the desired signal

38. - E7H05

How is positive feedback supplied in a Pierce oscillator?

SelectAnswer
AThrough a tapped coil
BThrough link coupling
CThrough a neutralizing capacitor
DThrough a quartz crystal

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
ADifferential analysis
BNumerical analysis
CVector analysis
DFourier analysis

40. - E8B02

How does the modulation index of a phase-modulated emission vary with RF carrier frequency?

SelectAnswer
AIt varies with the square root of the RF carrier frequency
BIt increases as the RF carrier frequency increases
CIt does not depend on the RF carrier frequency
DIt decreases as the RF carrier frequency increases

41. - E8C06

What is the bandwidth of a 170-hertz shift, 300-baud ASCII transmission?

SelectAnswer
A0.1 Hz
B0.3 kHz
C0.5 kHz
D1.0 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. - E9A11

Which of the following factors determines ground losses for a ground-mounted vertical antenna operating in the 3 MHz to 30 MHz range?

SelectAnswer
AThe standing wave ratio
BTake-off angle
CSoil conductivity
DDistance from the transmitter

44. - E9B09

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

SelectAnswer
AMutual impedance analysis
BCalculus differentiation with respect to physical properties
CMethod of Moments
DGraphical analysis

45. - E9C01

What is the radiation pattern of two 1/4-wavelength vertical antennas spaced 1/2-wavelength apart and fed 180 degrees out of phase?

SelectAnswer
AOmni-directional
BA figure-8 broadside to the axis of the array
CCardioid
DA figure-8 oriented along the axis of the array

46. - E9D02

How can linearly polarized Yagi antennas be used to produce circular polarization?

SelectAnswer
AStack two Yagis fed in phase to form an array with the respective elements in parallel planes
BStack two Yagis fed 90 degrees out of phase to form an array with the respective elements in parallel planes
CArrange two Yagis collinear to each other with the driven elements fed 180 degrees out of phase
DArrange two Yagis perpendicular to each other with the driven elements at the same point on the boom fed 90 degrees out of phase

47. - E9E05

How must an antenna's driven element be tuned to use a hairpin matching system?

SelectAnswer
AThe driven element resonance must be lower than the operating frequency
BThe driven element reactance must be inductive
CThe driven element reactance must be capacitive
DThe driven element radiation resistance must be higher than the characteristic impedance of the transmission line

48. - E9F09

What is the approximate physical length of a foam polyethylene dielectric coaxial transmission line that is electrically 1/4 wavelength long at 7.2 MHz?

SelectAnswer
A6.9 meters
B5.2 meters
C10.4 meters
D8.3 meters

49. - E9G10

What do the arcs on a Smith chart represent?

SelectAnswer
APoints with constant reactance
BSWR
CFrequency
DPoints with constant resistance

50. - E9H11

What feature of a cardioid pattern antenna makes it useful for direction finding?

SelectAnswer
AA very sharp single null
BBroadband response
CHigh radiation angle
DA very sharp peak

Figure E5-1

Figure E7-2