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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
BSynthetic Aperture Ratio of the human body
CThe rate at which RF energy is absorbed by the body
DSignal Amplification Rating

2. - E1A14

Except in some parts of Alaska, what is the maximum power permitted on the 630 meter band?

SelectAnswer
A1 watt EIRP
B100 watts PEP
C50 watts PEP
D5 watts EIRP

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

4. - E1C09

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

SelectAnswer
A3.0
B1.0
C0.5
D2.0

5. - E1D03

What is a space telecommand station?

SelectAnswer
AAn amateur station that transmits communications to initiate, modify or terminate functions of a space station
BAn amateur station located on the surface of the Earth for communication with other Earth stations by means of Earth satellites
CAn amateur station located in a satellite or a balloon more than 50 kilometers above the surface of the Earth
DAn amateur station that receives telemetry from a satellite or balloon more than 50 kilometers above the surface of the Earth

6. - E1E09

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

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

7. - E1F02

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

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

8. - E2A02

Which of the following occurs when a satellite is using an inverting linear transponder?

SelectAnswer
AUpper sideband on the uplink becomes lower sideband on the downlink, and vice versa
BSignal position in the band is reversed
CAll these choices are correct
DDoppler shift is reduced because the uplink and downlink shifts are in opposite directions

9. - E2B01

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

SelectAnswer
A120
B90
C60
D30

10. - E2C04

Which of the following frequencies are sometimes used for amateur radio mesh networks?

SelectAnswer
AFrequencies shared with various unlicensed wireless data services
BHF frequencies where digital communications are permitted
CThe 60 meter band channel centered on 5373 kHz
DCable TV channels 41 through 43

11. - E2D05

What is one advantage of the JT65 mode?

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

12. - E2E01

Which of the following types of modulation is common for data emissions below 30 MHz?

SelectAnswer
APulse modulation
BSpread spectrum
CFSK
DDTMF tones modulating an FM signal

13. - E3A14

What is meant by circularly polarized electromagnetic waves?

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

14. - E3B02

What is the approximate maximum range for signals using transequatorial propagation?

SelectAnswer
A2500 miles
B1000 miles
C7500 miles
D5000 miles

15. - E3C08

What does the space weather term G5 mean?

SelectAnswer
AWaning sunspot numbers
BModerate solar wind
CVery low solar activity
DAn extreme geomagnetic storm

16. - E4A01

Which of the following limits the highest frequency signal that can be accurately displayed on a digital oscilloscope?

SelectAnswer
AAmount of memory
BQ of the circuit
CAll these choices are correct
DSampling rate of the analog-to-digital converter

17. - E4B03

Which S parameter is equivalent to forward gain?

SelectAnswer
AS22
BS12
CS21
DS11

18. - E4C15

What is reciprocal mixing?

SelectAnswer
ALocal oscillator phase noise mixing with adjacent strong signals to create interference to desired signals
BIn-phase signals cancelling in a mixer resulting in loss of receiver sensitivity
CTwo digital signals combining from alternate time slots
DTwo out-of-band signals mixing to generate an in-band spurious signal

19. - E4D07

Which of the following reduces the likelihood of receiver desensitization?

SelectAnswer
ADecrease the RF bandwidth of the receiver
BIncrease the receiver front end gain
CSwitch from fast AGC to slow AGC
DRaise the receiver IF frequency

20. - E4E08

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

SelectAnswer
AReturn current
BCommon-mode current
CDifferential-mode current
DReactive current only

21. - E5A08

What is the phase relationship between the current through and the voltage across a series resonant circuit at resonance?

SelectAnswer
AThe voltage and current are in phase
BThe voltage and current are 180 degrees out of phase
CThe voltage leads the current by 90 degrees
DThe current leads the voltage by 90 degrees

22. - E5B08

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 100 ohms, R is 100 ohms, and XL is 75 ohms?

SelectAnswer
A14 degrees with the voltage lagging the current
B76 degrees with the voltage lagging the current
C14 degrees with the voltage leading the current
D76 degrees with the voltage leading the current

23. - E5C01

Which of the following represents capacitive reactance in rectangular notation?

SelectAnswer
A+jX
BDelta
C-jX
DOmega

24. - E5D07

How many watts are consumed in a circuit having a power factor of 0.71 if the apparent power is 500VA?

SelectAnswer
A355 W
B252 W
C704 W
D1.42 mW

25. - E6A03

Why does a PN-junction diode not conduct current when reverse biased?

SelectAnswer
AExcess holes in P-type material combine with the electrons in N-type material, converting the entire diode into an insulator
BHoles in P-type material and electrons in the N-type material are separated by the applied voltage, widening the depletion region
COnly N-type semiconductor material can conduct current
DOnly P-type semiconductor material can conduct current

26. - E6B03

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

SelectAnswer
AForward bias
BInductive bias
CZero bias
DReverse bias

27. - E6C10

In Figure E6-3, what is the schematic symbol for a NOR gate?

SelectAnswer
A1
B2
C3
D4

28. - E6D03

Which of the following is an aspect of the piezoelectric effect?

SelectAnswer
AIncreased conductivity in the presence of light
BGeneration of electrical energy in the presence of light
CMechanical deformation of material by the application of a voltage
DMechanical deformation of material by the application of a magnetic field

29. - E6E01

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

SelectAnswer
AHigher noise figures
BHigher electron mobility
CLower transconductance
DLower junction voltage drop

30. - E6F10

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

SelectAnswer
ASelenium
BCopper oxide
CCadmium Sulfide
DSilicon

31. - E7A01

Which circuit is bistable?

SelectAnswer
AAn AND gate
BA flip-flop
CA bipolar amplifier
DAn OR gate

32. - E7B09

Which of the following describes how the loading and tuning capacitors are to be adjusted when tuning a vacuum tube RF power amplifier that employs a Pi-network output circuit?

SelectAnswer
AThe loading capacitor is adjusted to minimum plate current while alternately adjusting the tuning capacitor for maximum allowable plate current
BThe loading capacitor is set to maximum capacitance and the tuning capacitor is adjusted for minimum allowable plate current
CThe tuning capacitor is adjusted for minimum plate current, and the loading capacitor is adjusted for maximum permissible plate current
DThe tuning capacitor is set to maximum capacitance and the loading capacitor is adjusted for minimum plate permissible current

33. - E7C08

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

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

34. - E7D05

Which of the following types of linear voltage regulator places a constant load on the unregulated voltage source?

SelectAnswer
AA constant current source
BA shunt current source
CA shunt regulator
DA series regulator

35. - E7E10

How does a diode envelope detector function?

SelectAnswer
ABy sensing the change of reactance in the diode with respect to frequency
BBy mixing signals with noise in the transition region of the diode
CBy breakdown of the Zener voltage
DBy rectification and filtering of RF signals

36. - E7F08

What is the function of decimation?

SelectAnswer
AConverting data to binary code decimal form
BRemoving unnecessary significant digits
CAttenuating the signal
DReducing the effective sample rate by removing samples

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 output voltage of the op-amp minus its input voltage
CThe difference between the output voltage of the op-amp and the input voltage required in the immediately following stage
DThe differential input voltage needed to bring the open loop output voltage to zero

38. - E7H09

What type of frequency synthesizer circuit uses a phase accumulator, lookup table, digital to analog converter, and a low-pass anti-alias filter?

SelectAnswer
AA hybrid synthesizer
BA direct digital synthesizer
CA phase-locked loop synthesizer
DA diode-switching matrix synthesizer

39. - E8A09

How many different input levels can be encoded by an analog-to-digital converter with 8-bit resolution?

SelectAnswer
A8 multiplied by the gain of the input amplifier
B8
C256 divided by the gain of the input amplifier
D256

40. - E8B09

What is deviation ratio?

SelectAnswer
AThe ratio of the maximum carrier frequency deviation to the highest audio modulating frequency
BThe ratio of the highest audio modulating frequency to the average audio modulating frequency
CThe ratio of the carrier center frequency to the audio modulating frequency
DThe ratio of the audio modulating frequency to the center carrier frequency

41. - E8C01

How is Forward Error Correction implemented?

SelectAnswer
ABy transmitting extra data that may be used to detect and correct transmission errors
BBy the receiving station repeating each block of three data characters
CBy varying the frequency shift of the transmitted signal according to a predefined algorithm
DBy transmitting a special algorithm to the receiving station along with the data characters

42. - E8D05

What is the most common method of reducing key clicks?

SelectAnswer
AReduce keying waveform rise and fall times
BIncrease keying waveform rise and fall times
CLow-pass filters at the transmitter output
DHigh-pass filters at the transmitter output

43. - E9A12

How much gain does an antenna have compared to a 1/2-wavelength dipole when it has 6 dB gain over an isotropic antenna?

SelectAnswer
A6.0 dB
B3.85 dB
C8.15 dB
D2.79 dB

44. - E9B02

In the antenna radiation pattern shown in Figure E9-1, what is the front-to-back ratio?

SelectAnswer
A14 dB
B24 dB
C18 dB
D36 dB

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

46. - E9D04

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

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

47. - E9E06

Which of these feed line impedances would be suitable for constructing a quarter-wave Q-section for matching a 100-ohm loop to 50-ohm feed line?

SelectAnswer
A62 ohms
B450 ohms
C50 ohms
D75 ohms

48. - E9F13

What impedance does a 1/4-wavelength transmission line present to a generator when the line is shorted at the far end?

SelectAnswer
AVery low impedance
BThe same as the characteristic impedance of the transmission line
CThe same as the generator output impedance
DVery high impedance

49. - E9G01

Which of the following can be calculated using a Smith chart?

SelectAnswer
AImpedance along transmission lines
BRadio propagation
CRadiation resistance
DAntenna radiation pattern

50. - E9H05

What is the main drawback of a small wire-loop antenna for direction finding?

SelectAnswer
AIt has no clearly defined null
BAll these choices are correct
CIt is practical for use only on VHF and higher bands
DIt has a bidirectional pattern

Figure E6-3

Figure E9-1