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

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1. - E0A01

What is the primary function of an external earth connection or ground rod?

SelectAnswer
AReduce RF current flow between pieces of equipment
BLightning protection
CReduce RFI to telephones and home entertainment systems
DReduce received noise

2. - E1A07

What is the maximum power permitted on the 2200 meter band?

SelectAnswer
A5 watts EIRP (Equivalent isotropic radiated power)
B50 watts PEP
C1 watt EIRP (Equivalent isotropic radiated power)
D100 watts PEP

3. - E1B03

Within what distance must an amateur station protect an FCC monitoring facility from harmful interference?

SelectAnswer
A10 miles
B3 miles
C30 miles
D1 mile

4. - E1C13

What notifications must be given before transmitting on the 630 meter or 2200 meter bands?

SelectAnswer
AAn environmental impact statement must be filed with the Department of the Interior
BA special endorsement must be requested from the FCC
COperators must inform the FAA of their intent to operate, giving their call sign and distance to the nearest runway
DOperators must inform the Utilities Technology Council (UTC) of their call sign and coordinates of the station

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 label with the name, address, and telephone number of the control operator
BA photocopy of the station license
CAll these choices are correct
DA label with the name, address, and telephone number of the station licensee

6. - E1E10

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

SelectAnswer
AThey must collect and submit the documents to the coordinating VEC for grading
BThey must collect and send the documents to the FCC according to instructions
CThey must collect and send the documents to the NCVEC for grading
DThey must submit the application document to the coordinating VEC according to the coordinating VEC instructions

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?

SelectAnswer
A222 MHz - 223 MHz
B420 MHz - 430 MHz
C440 MHz - 450 MHz
D53 MHz - 54 MHz

8. - E2A08

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

SelectAnswer
ATo avoid reducing the downlink power to all other users
BTo prevent creating errors in the satellite telemetry
CTo avoid interfering with terrestrial QSOs
DTo prevent the satellite from emitting out-of-band signals

9. - E2B05

Which of the following describes the use of vestigial sideband in analog fast-scan TV transmissions?

SelectAnswer
AThe vestigial sideband contains chroma information
BVestigial sideband provides high frequency emphasis to sharpen the picture
CThe vestigial sideband carries the audio information
DVestigial sideband reduces bandwidth while allowing for simple video detector circuitry

10. - E2C02

Which of the following best describes the term self-spotting? in connection with HF contest operating?

SelectAnswer
AThe acceptable practice of manually posting the call signs of stations on a spotting network
BA manual technique for rapidly zero beating or tuning to a station's frequency before calling that station
CAn automatic method for rapidly zero beating or tuning to a station's frequency before calling that station
DThe often-prohibited practice of posting one's own call sign and frequency on a spotting network

11. - E2D03

Which of the following digital modes is especially useful for EME communications?

SelectAnswer
AJT65
BOlivia
CMSK144
DPACTOR III

12. - E2E12

How do ALE stations establish contact?

SelectAnswer
AALE constantly scans a list of frequencies, activating the radio when the designated call sign is received
BALE radios send a constant tone code to establish a frequency for future use
CALE radios monitor an internet site for the frequency they are being paged on
DALE radios activate when they hear their signal echoed by back scatter

13. - E3A04

What do Hepburn maps predict?

SelectAnswer
ALocations of auroral reflecting zones
BLikelihood of rain scatter along cold or warm fronts
CProbability of tropospheric propagation
DSporadic E propagation

14. - E3B03

What is the best time of day for transequatorial propagation?

SelectAnswer
AAfternoon or early evening
BMorning
CNoon
DLate at night

15. - E3C02

What is indicated by a rising A or K index?

SelectAnswer
ADecreasing disruption of the geomagnetic field
BAn increase in the critical frequency
CHigher levels of solar UV radiation
DIncreasing disruption of the geomagnetic field

16. - E4A02

Which of the following parameters does a spectrum analyzer display on the vertical and horizontal axes?

SelectAnswer
ARF amplitude and frequency
BSWR and frequency
CSWR and time
DRF amplitude and time

17. - E4B10

Which of the following methods measures intermodulation distortion in an SSB transmitter?

SelectAnswer
AModulate the transmitter using two RF signals having harmonically related frequencies and observe the RF output with a logic analyzer
BModulate the transmitter using two RF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer
CModulate the transmitter using two AF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer
DModulate the transmitter using two AF signals having harmonically related frequencies and observe the RF output with a peak reading wattmeter

18. - E4C05

What does a receiver noise floor of -174 dBm represent?

SelectAnswer
AThe minimum detectable signal as a function of receive frequency
BThe galactic noise contribution to minimum detectable signal
CThe noise figure of a 1 Hz bandwidth receiver
DThe theoretical noise in a 1 Hz bandwidth at the input of a perfect receiver at room temperature

19. - E4D01

What is meant by the blocking dynamic range of a receiver?

SelectAnswer
AThe difference in dB between the noise floor and the level of an incoming signal that will cause 1 dB of gain compression
BThe minimum difference in dB between the levels of two FM signals that will cause one signal to block the other
CThe difference in dB between the noise floor and the third-order intercept point
DThe minimum difference in dB between two signals which produce third-order intermodulation products greater than the noise floor

20. - E4E09

What undesirable effect can occur when using an IF noise blanker?

SelectAnswer
AThe audio frequency bandwidth of the received signal might be compressed
BReceived audio in the speech range might have an echo effect
CFM signals can no longer be demodulated
DNearby signals may appear to be excessively wide even if they meet emission standards

21. - E5A07

What is the magnitude of the current at the input of a parallel RLC circuit at resonance?

SelectAnswer
AMinimum
BMaximum
CL/R
DR/L

22. - E5B10

What is the relationship between the AC current through an inductor and the voltage across an inductor?

SelectAnswer
ACurrent leads voltage by 90 degrees
BVoltage and current are 180 degrees out of phase
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 1
BPoint 3
CPoint 8
DPoint 7

24. - E5D12

How many watts are consumed in a circuit having a power factor of 0.2 if the input is 100 VAC at 4 amperes?

SelectAnswer
A80 watts
B2000 watts
C50 watts
D400 watts

25. - E6A12

Why do many MOSFET devices have internally connected Zener diodes on the gates?

SelectAnswer
ATo reduce the chance of static damage to the gate
BTo protect the substrate from excessive voltages
CTo keep the gate voltage within specifications and prevent the device from overheating
DTo provide a voltage reference for the correct amount of reverse-bias gate voltage

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
BLonger carrier retention time
CMuch higher reverse voltage breakdown
DMore constant reverse avalanche voltage

27. - E6C06

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

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

28. - E6D04

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

SelectAnswer
ATeflon and Delrin
BCobalt and aluminum
CFerrite and brass
DPolystyrene and polyethylene

29. - E6E11

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

SelectAnswer
ALow leakage doubly insulated package
BA total of two rows of connecting pins placed on opposite sides of the package (Dual In-line Package)
CTwo chips in each package (Dual In Package)
DPackage mounts in a direct inverted position

30. - E6F07

What is a solid-state relay?

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

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

32. - E7B18

What is a characteristic of a grounded-grid amplifier?

SelectAnswer
ALow input impedance
BHigh power gain
CHigh filament voltage
DLow bandwidth

33. - E7C04

How does an impedance-matching circuit transform a complex impedance to a resistive impedance?

SelectAnswer
AIt cancels the reactive part of the impedance and changes the resistive part to a desired value
BReactive currents are dissipated in matched resistances
CIt introduces negative resistance to cancel the resistive part of impedance
DIt introduces transconductance to cancel the reactive part of impedance

34. - E7D15

What is the purpose of a step-start circuit in a high-voltage power supply?

SelectAnswer
ATo provide a dual-voltage output for reduced power applications
BTo allow the filter capacitors to charge gradually
CTo compensate for variations of the incoming line voltage
DTo allow for remote control of the power supply

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 oscillator
DA reactance modulator on the final amplifier

36. - E7F05

How frequently must an analog signal be sampled by an analog-to-digital converter so that the signal can be accurately reproduced?

SelectAnswer
AAt the same rate as the highest frequency component of the signal
BAt least twice the rate of the highest frequency component of the signal
CAt four times the rate of the highest frequency component of the signal
DAt least half the rate of the highest frequency component of the signal

37. - E7G02

What is ringing in a filter?

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

38. - E7H07

How can an oscillator's microphonic responses be reduced?

SelectAnswer
AUse NP0 capacitors
BReduce noise on the oscillator's power supply
CMechanically isolate the oscillator circuitry from its enclosure
DIncrease the bias voltage

39. - E8A08

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

SelectAnswer
AImmunity to out-of-sequence coding reduces spurious responses
BAll these choices are correct
CVery low power consumption decreases frequency drift
DVery high speed allows digitizing high frequencies

40. - E8B03

What is the modulation index of an FM-phone signal having a maximum frequency deviation of 3000 Hz either side of the carrier frequency when the modulating frequency is 1000 Hz?

SelectAnswer
A0.3
B3000
C3
D1000

41. - E8C12

What factors affect the bandwidth of a transmitted CW signal?

SelectAnswer
AKeying speed and shape factor (rise and fall time)
BAll these choices are correct
CIF bandwidth and Q
DModulation index and output power

42. - E8D03

How does the spread spectrum technique of frequency hopping work?

SelectAnswer
AIf interference is detected by the receiver it will signal the transmitter to change frequencies
BThe frequency of the transmitted signal is changed very rapidly according to a pseudorandom sequence also used by the receiving station
CIf interference is detected by the receiver it will signal the transmitter to wait until the frequency is clear
DA binary bit stream is used to shift the phase of an RF carrier very rapidly in a pseudorandom sequence

43. - E9A05

What is included in the total resistance of an antenna system?

SelectAnswer
ATransmission-line resistance plus radiation resistance
BRadiation resistance plus transmission resistance
CRadiation resistance plus space impedance
DRadiation resistance plus loss resistance

44. - E9B08

What is the far field of an antenna?

SelectAnswer
AThe region where radiated field strengths are constant
BThe region of the ionosphere where radiated power is not refracted
CThe region where radiated power dissipates over a specified time period
DThe region where the shape of the antenna pattern is independent of distance

45. - E9C07

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

SelectAnswer
A50 ohms
B450 ohms
C300 ohms
D72 ohms

46. - E9D07

What is an advantage of using top loading in a shortened HF vertical antenna?

SelectAnswer
AGreater structural strength
BHigher losses
CLower Q
DImproved radiation efficiency

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. - E9F10

What impedance does a 1/8-wavelength transmission line present to a generator when the line is shorted at the far end?

SelectAnswer
AThe same as the characteristic impedance of the line
BA capacitive reactance
CZero
DAn inductive reactance

49. - E9G03

Which of the following is often determined using a Smith chart?

SelectAnswer
ASatellite azimuth and elevation bearings
BTrigonometric functions
CImpedance and SWR values in transmission lines
DBeam headings and radiation patterns

50. - E9H02

Which is generally true for low band (160 meter and 80 meter) receiving antennas?

SelectAnswer
ALow loss coax transmission line is essential for good performance
BAll these choices are correct
CAtmospheric noise is so high that gain over a dipole is not important
DThey must be erected at least 1/2 wavelength above the ground to attain good directivity

Figure E5-1