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

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?

SelectAnswer
A300 Hz above the lower band edge
BThe exact lower band edge
C3 kHz above the lower band edge
D1 kHz above the lower band edge

3. - E1B06

Which of the following additional rules apply if you are installing an amateur station antenna at a site at or near a public use airport?

SelectAnswer
AYou must file an Environmental Impact Statement with the EPA before construction begins
BYou must submit engineering drawings to the FAA
CYou may have to notify the Federal Aviation Administration and register it with the FCC as required by Part 17 of the FCC rules
DYou must obtain a construction permit from the airport zoning authority

4. - E1C06

Which of the following is required in order to operate in accordance with CEPT rules in foreign countries where permitted?

SelectAnswer
AYou must identify in the official language of the country in which you are operating
BThe U.S. embassy must approve of your operation
CYou must append "/CEPT" to your call sign
DYou must bring a copy of FCC Public Notice DA 16-1048

5. - E1D01

What is the definition of telemetry?

SelectAnswer
AOne-way transmission that initiates, modifies, or terminates the functions of a device at a distance
BOne-way transmission of measurements at a distance from the measuring instrument
CTwo-way transmissions in excess of 1000 feet
DTwo-way transmissions of data

6. - E1E09

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

SelectAnswer
AA fine of up to $1000 per occurrence
BRevocation of the VE's amateur station license grant and the suspension of the VE's amateur operator license grant
CA sentence of up to one year in prison
DAll these choices are correct

7. - E1F02

What privileges are authorized in the U.S. to persons holding an amateur service license granted by the government of Canada?

SelectAnswer
AFull privileges, up to and including those of the Amateur Extra Class license, on the 80, 40, 20, 15, and 10 meter bands
BAll privileges of the Amateur Extra Class license
CThe operating terms and conditions of the Canadian amateur service license, not to exceed U.S. Amateur Extra Class license privileges
DNone, they must obtain a U.S. license

8. - E2A06

What are Keplerian elements?

SelectAnswer
AParameters that define the orbit of a satellite
BEncrypting codes used for spread spectrum modulation
CHigh-emission heater filaments used in magnetron tubes
DPhase reversing elements in a Yagi antenna

9. - E2B09

What hardware, other than a receiver with SSB capability and a suitable computer, is needed to decode SSTV using Digital Radio Mondiale (DRM)?

SelectAnswer
AA special notch filter to remove synchronization pulses
BNo other hardware is needed
CA special IF converter
DA special front end limiter

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 only the last two letters of your call sign until you make contact
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 once or twice
DSend your full call sign and grid square

11. - E2D03

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

SelectAnswer
APACTOR III
BJT65
COlivia
DMSK144

12. - E2E08

Which of the following HF digital modes can be used to transfer binary files?

SelectAnswer
ARTTY
BPACTOR
CHellschreiber
DAMTOR

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?

SelectAnswer
ASwitch to a higher frequency HF band
BWait 24 hours before attempting another communication on the band
CSwitch to a lower frequency HF band
DWait 90 minutes or so for the signal degradation to pass

14. - E3B03

What is the best time of day for transequatorial propagation?

SelectAnswer
ALate at night
BNoon
CMorning
DAfternoon or early evening

15. - E3C13

What type of polarization is best for ground-wave propagation?

SelectAnswer
AElliptical
BVertical
CHorizontal
DCircular

16. - E4A09

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

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

17. - E4B11

Which of the following can be measured with a vector network analyzer?

SelectAnswer
AAll these choices are correct
BInput impedance
COutput impedance
DReflection coefficient

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
AEasier for front-end circuitry to eliminate image responses
BReduced drift
CImproved receiver noise figure
DFewer components in the receiver

19. - E4D08

What causes intermodulation in an electronic circuit?

SelectAnswer
ANonlinear circuits or devices
BLack of neutralization
CPositive feedback
DToo little gain

20. - E4E08

What current flows equally on all conductors of an unshielded multi-conductor cable?

SelectAnswer
ADifferential-mode current
BReturn current
CReactive current only
DCommon-mode current

21. - E5A14

What is the resonant frequency of an RLC circuit if R is 22 ohms, L is 50 microhenries and C is 40 picofarads?

SelectAnswer
A22.36 MHz
B3.56 MHz
C1.78 MHz
D44.72 MHz

22. - E5B02

What letter is commonly used to represent susceptance?

SelectAnswer
AX
BY
CG
DB

23. - E5C10

Which point on Figure E5-1 best represents the impedance of a series circuit consisting of a 400-ohm resistor and a 38-picofarad capacitor at 14 MHz?

SelectAnswer
APoint 6
BPoint 2
CPoint 5
DPoint 4

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
A400 watts
B2000 watts
C80 watts
D50 watts

25. - E6A05

How does DC input impedance at the gate of a field-effect transistor compare with the DC input impedance of a bipolar transistor?

SelectAnswer
AThey are both high impedance
BThey are both low impedance
CAn FET has lower input impedance
DAn FET has higher input impedance

26. - E6B03

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

SelectAnswer
AInductive bias
BReverse bias
CZero bias
DForward bias

27. - E6C07

What best describes a pull-up or pull-down resistor?

SelectAnswer
AA resistor that ensures that an oscillator frequency does not drift
BA resistor connected to the positive or negative supply line used to establish a voltage when an input or output is an open circuit
CA resistor in a keying circuit used to reduce key clicks
DA resistor connected to an op-amp output that prevents signals from exceeding the power supply voltage

28. - E6D07

What is current in the primary winding of a transformer called if no load is attached to the secondary?

SelectAnswer
ADirect current
BMagnetizing current
CExcitation current
DStabilizing current

29. - E6E05

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

SelectAnswer
A-20 dBm
B-10 dB
C2 dB
D44 dBm

30. - E6F08

Why are optoisolators often used in conjunction with solid-state circuits when switching 120 VAC?

SelectAnswer
AOptoisolators provide a low impedance link between a control circuit and a power circuit
BOptoisolators provide a very high degree of electrical isolation between a control circuit and the circuit being switched
COptoisolators eliminate the effects of reflected light in the control circuit
DOptoisolators provide impedance matching between the control circuit and power circuit

31. - E7A02

What is the function of a decade counter?

SelectAnswer
AIt produces 10 output pulses for every input pulse
BIt decodes a binary number for display on a seven-segment LED display
CIt decodes a decimal number for display on a seven-segment LED display
DIt produces one output pulse for every 10 input pulses

32. - E7B03

Which of the following components form the output of a class D amplifier circuit?

SelectAnswer
AA low-pass filter to remove switching signal components
BA matched load resistor to prevent damage by switching transients
CA high-pass filter to compensate for low gain at low frequencies
DA temperature compensating load resistor to improve linearity

33. - E7C09

What is a crystal lattice filter?

SelectAnswer
AA power supply filter made with interlaced quartz crystals
BA filter using lattice-shaped quartz crystals for high-Q performance
CAn audio filter made with four quartz crystals that resonate at 1 kHz intervals
DA filter with narrow bandwidth and steep skirts made using quartz crystals

34. - E7D10

What is the primary reason that a high-frequency switching type high-voltage power supply can be both less expensive and lighter in weight than a conventional power supply?

SelectAnswer
AIt uses a large power factor compensation capacitor to recover power from the unused portion of the AC cycle
BThe inverter design does not require any output filtering
CIt uses a diode bridge rectifier for increased output
DThe high frequency inverter design uses much smaller transformers and filter components for an equivalent power output

35. - E7E07

What is meant by the term "baseband" in radio communications?

SelectAnswer
AThe lowest frequency band that the transmitter or receiver covers
BThe frequency range occupied by a message signal prior to modulation
CThe unmodulated bandwidth of the transmitted signal
DThe basic oscillator frequency in an FM transmitter that is multiplied to increase the deviation and carrier frequency

36. - E7F14

Which of the following would allow a digital signal processing filter to create a sharper filter response?

SelectAnswer
ADouble-precision math routines
BComplex phasor representations
CMore taps
DHigher data rate

37. - E7G05

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

SelectAnswer
ARestrict gain but increase Q
BRestrict Q but increase gain
CIncrease both gain and Q
DRestrict both gain and Q

38. - E7H10

What information is contained in the lookup table of a direct digital synthesizer (DDS)?

SelectAnswer
AFrequently used receiver and transmitter frequencies
BThe phase relationship between a reference oscillator and the output waveform
CAmplitude values that represent the desired waveform
DThe phase relationship between a voltage-controlled oscillator and the output waveform

39. - E8A03

What type of wave does a Fourier analysis show to be made up of sine waves of a given fundamental frequency plus all its harmonics?

SelectAnswer
AA square wave
BA cosine wave
CA sawtooth wave
DA sine wave

40. - E8B06

What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus or minus 7.5 kHz when the maximum modulation frequency is 3.5 kHz?

SelectAnswer
A2.14
B0.214
C47
D0.47

41. - E8C11

What is the relationship between symbol rate and baud?

SelectAnswer
ABaud is twice the symbol rate
BThey are the same
CBaud is only used for RTTY
DSymbol rate is only used for packet-based modes

42. - E8D06

What is the advantage of including parity bits in ASCII characters?

SelectAnswer
ASome types of errors can be detected
BFaster transmission rate
CThe signal can overpower interfering signals
DForeign language characters can be sent

43. - E9A05

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

SelectAnswer
ARadiation resistance plus loss resistance
BTransmission-line resistance plus radiation resistance
CRadiation resistance plus transmission resistance
DRadiation resistance plus space impedance

44. - E9B07

How does the total amount of radiation emitted by a directional gain antenna compare with the total amount of radiation emitted from a theoretical isotropic antenna, assuming each is driven by the same amount of power?

SelectAnswer
AThe radiation from the isotropic antenna is 2.15 dB stronger than that from the directional antenna
BThe total amount of radiation from the directional antenna is increased by the gain of the antenna
CThe total amount of radiation from the directional antenna is stronger by its front-to-back ratio
DThey are the same

45. - E9C14

How does the performance of a horizontally polarized antenna mounted on the side of a hill compare with the same antenna mounted on flat ground?

SelectAnswer
AThe horizontal beamwidth increases in the uphill direction
BThe main lobe takeoff angle decreases in the downhill direction
CThe main lobe takeoff angle increases in the downhill direction
DThe horizontal beamwidth decreases in the downhill direction

46. - E9D09

What is the function of a loading coil used as part of an HF mobile antenna?

SelectAnswer
ATo lower the losses
BTo increase the SWR bandwidth
CTo cancel capacitive reactance
DTo lower the Q

47. - E9E10

Which of these choices is an effective way to match an antenna with a 100-ohm feed point impedance to a 50-ohm coaxial cable feed line?

SelectAnswer
AInsert a 1/4-wavelength piece of 75-ohm coaxial cable transmission line in series between the antenna terminals and the 50-ohm feed cable
BConnect a 1/2 wavelength shorted stub of 75-ohm cable in parallel with the 50-ohm cable where it attaches to the antenna
CConnect a 1/4-wavelength open stub of 300-ohm twinlead in parallel with the coaxial feed line where it connects to the antenna
DInsert a 1/2 wavelength piece of 300-ohm twinlead in series between the antenna terminals and the 50-ohm feed cable

48. - E9F02

Which of the following has the biggest effect on the velocity factor of a transmission line?

SelectAnswer
AThe center conductor resistivity
BDielectric materials used in the line
CThe line length
DThe termination impedance

49. - E9G05

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

SelectAnswer
ADetermine the gain of an antenna given the physical and electrical parameters
BDetermine the loss/100 feet of a transmission line, given the velocity factor and conductor materials
CDetermine the length and position of an impedance matching stub
DDetermine the impedance of a transmission line, given the physical dimensions

50. - E9H01

When constructing a Beverage antenna, which of the following factors should be included in the design to achieve good performance at the desired frequency?

SelectAnswer
AIt should be one or more wavelengths long
BIt should be configured as a four-sided loop
CIt must be mounted more than 1 wavelength above ground
DIts overall length must not exceed 1/4 wavelength

Figure E5-1