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

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1. - E0A04

When evaluating a site with multiple transmitters operating at the same time, the operators and licensees of which transmitters are responsible for mitigating over-exposure situations?

SelectAnswer
AEach transmitter that produces 5 percent or more of its MPE limit in areas where the total MPE limit is exceeded.
BEach transmitter operating with a duty cycle greater than 50 percent
COnly the most powerful transmitter
DOnly commercial transmitters

2. - E1A03

What is the maximum legal carrier frequency on the 20 meter band for transmitting USB AFSK digital signals having a 1 kHz bandwidth?

SelectAnswer
A14.070 MHz
B14.149 MHz
C14.349 MHz
D14.100 MHz

3. - E1B09

Which amateur stations may be operated under RACES rules?

SelectAnswer
AAny FCC-licensed amateur station participating in the Military Auxiliary Radio System (MARS)
BAny FCC-licensed amateur station except a Technician Class
COnly those club stations licensed to Amateur Extra Class operators
DAny FCC-licensed amateur station certified by the responsible civil defense organization for the area served

4. - E1C10

What is the permitted mean power of any spurious emission relative to the mean power of the fundamental emission from a station transmitter or external RF amplifier installed after January 1, 2003 and transmitting on a frequency below 30 MHz?

SelectAnswer
AAt least 43 dB below
BAt least 73 dB below
CAt least 63 dB below
DAt least 53 dB below

5. - E1D01

What is the definition of telemetry?

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

6. - E1E02

Who does Part 97 task with maintaining the pools of questions for all U.S. amateur license examinations?

SelectAnswer
AThe VECs
BThe VEs
CThe FCC
DThe ARRL

7. - E1F06

Under what circumstances might the FCC issue a Special Temporary Authority (STA) to an amateur station?

SelectAnswer
ATo provide additional spectrum for personal use
BTo provide temporary operation while awaiting normal licensing
CTo allow regular operation on Land Mobile channels
DTo provide for experimental amateur communications

8. - E2A03

How is the signal inverted by an inverting linear transponder?

SelectAnswer
AThe signal is detected and remodulated on the reverse sideband
BThe signal is reduced to I and Q components and the Q component is filtered out
CThe signal is passed through a non-linear filter
DThe signal is passed through a mixer and the difference rather than the sum is transmitted

9. - E2B07

What is the name of the signal component that carries color information in NTSC video?

SelectAnswer
ASpectral intensity
BLuminance
CChroma
DHue

10. - E2C03

From which of the following bands is amateur radio contesting generally excluded?

SelectAnswer
A30 meters
B6 meters
C33 centimeters
D2 meters

11. - E2D11

Which of the following data are used by the APRS network to communicate station location?

SelectAnswer
APolar coordinates
BTime and frequency
CRadio direction finding spectrum analysis
DLatitude and longitude

12. - E2E04

What is indicated when one of the ellipses in an FSK crossed-ellipse display suddenly disappears?

SelectAnswer
AThe mark and space signal have been inverted
BSelective fading has occurred
CThe receiver has drifted 5 kHz from the desired receive frequency
DOne of the signal filters is saturated

13. - E3A01

What is the approximate maximum separation measured along the surface of the Earth between two stations communicating by EME?

SelectAnswer
A12,000 miles, if the moon is visible by both stations
B500 miles, if the moon is at perigee
C2000 miles, if the moon is at apogee
D5000 miles, if the moon is at perigee

14. - E3B02

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

SelectAnswer
A7500 miles
B5000 miles
C2500 miles
D1000 miles

15. - E3C13

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

SelectAnswer
AElliptical
BHorizontal
CVertical
DCircular

16. - E4A11

How should an antenna analyzer be connected when measuring antenna resonance and feed point impedance?

SelectAnswer
AConnect the analyzer via a high-impedance transformer to the antenna
BConnect the antenna feed line directly to the analyzer's connector
CLoosely couple the antenna and a dummy load to the analyzer
DLoosely couple the analyzer near the antenna base

17. - E4B11

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

SelectAnswer
AAll these choices are correct
BReflection coefficient
COutput impedance
DInput impedance

18. - E4C10

What is an advantage of having a variety of receiver IF bandwidths from which to select?

SelectAnswer
AReceive bandwidth can be set to match the modulation bandwidth, maximizing signal-to-noise ratio and minimizing interference
BReceiver power consumption can be reduced when wider bandwidth is not required
CMultiple frequencies can be received simultaneously if desired
DThe noise figure of the RF amplifier can be adjusted to match the modulation type, thus increasing receiver sensitivity

19. - E4D12

What is the term for the reduction in receiver sensitivity caused by a strong signal near the received frequency?

SelectAnswer
ASquelch gain rollback
BDesensitization
CQuieting
DCross-modulation interference

20. - E4E05

How can radio frequency interference from an AC motor be suppressed?

SelectAnswer
ABy installing a brute-force AC-line filter in series with the motor leads
BBy installing a high-pass filter in series with the motor's power leads
CBy using a ground-fault current interrupter in the circuit used to power the motor
DBy installing a bypass capacitor in series with the motor leads

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
B23.67 kHz
C47.3 kHz
D315.6 Hz

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 leading the current
C76 degrees with the voltage lagging the current
D14 degrees with the voltage leading the current

23. - E5C04

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

SelectAnswer
AMaidenhead grid
BElliptical coordinates
CFaraday grid
DRectangular coordinates

24. - E5D03

What is microstrip?

SelectAnswer
AShort lengths of coax mounted on printed circuit boards to minimize time delay between microwave circuits
BLightweight transmission line made of common zip cord
CPrecision printed circuit conductors above a ground plane that provide constant impedance interconnects at microwave frequencies
DMiniature coax used for low power applications

25. - E6A02

Which of the following semiconductor materials contains excess free electrons?

SelectAnswer
AInsulated gate
BBipolar
CN-type
DP-type

26. - E6B08

Which of the following is a Schottky barrier diode?

SelectAnswer
APIN junction
BMetal-semiconductor junction
CElectrolytic rectifier
DThermionic emission diode

27. - E6C04

Which of the following is an advantage of BiCMOS logic?

SelectAnswer
AIt has the high input impedance of CMOS and the low output impedance of bipolar transistors
BAll these choices are correct
CIt is immune to electrostatic damage
DIts simplicity results in much less expensive devices than standard CMOS

28. - E6D10

What is a primary advantage of using a toroidal core instead of a solenoidal core in an inductor?

SelectAnswer
AToroidal cores make it easier to couple the magnetic energy into other components
BToroidal cores exhibit greater hysteresis
CToroidal cores have lower Q characteristics
DToroidal cores confine most of the magnetic field within the core material

29. - E6E11

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

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

30. - E6F11

What is the approximate open-circuit voltage produced by a fully illuminated silicon photovoltaic cell?

SelectAnswer
A1.5 V
B0.5 V
C0.1 V
D12 V

31. - E7A11

What type of logic defines "1" as a high voltage?

SelectAnswer
AAssertive Logic
BReverse Logic
CNegative logic
DPositive Logic

32. - E7B04

Where on the load line of a Class A common emitter amplifier would bias normally be set?

SelectAnswer
AAt a point where the load line intersects the zero bias current curve
BWhere the load line intersects the voltage axis
CApproximately halfway between saturation and cutoff
DAt a point where the bias resistor equals the load resistor

33. - E7C01

How are the capacitors and inductors of a low-pass filter Pi-network arranged between the network's input and output?

SelectAnswer
AAn inductor is connected between the input and ground, another inductor is connected between the output and ground, and a capacitor is connected between the input and output
BTwo capacitors are in series between the input and output, and an inductor is connected between the two capacitors and ground
CTwo inductors are in series between the input and output, and a capacitor is connected between the two inductors and ground
DA capacitor is connected between the input and ground, another capacitor is connected between the output and ground, and an inductor is connected between input and output

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

35. - E7E08

What are the principal frequencies that appear at the output of a mixer circuit?

SelectAnswer
ATwo and four times the original frequency
B1.414 and 0.707 times the input frequency
CThe square root of the product of input frequencies
DThe two input frequencies along with their sum and difference frequencies

36. - E7F10

What aspect of receiver analog-to-digital conversion determines the maximum receive bandwidth of a Direct Digital Conversion SDR?

SelectAnswer
ASample clock phase noise
BSample width in bits
CProcessor latency
DSample rate

37. - E7G11

What absolute voltage gain can be expected from the circuit in Figure E7-3 when R1 is 3300 ohms and RF is 47 kilohms?

SelectAnswer
A7
B0.07
C14
D28

38. - E7H10

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

SelectAnswer
AThe phase relationship between a reference oscillator and the output waveform
BAmplitude values that represent the desired waveform
CThe phase relationship between a voltage-controlled oscillator and the output waveform
DFrequently used receiver and transmitter frequencies

39. - E8A08

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

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

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
A3000
B3
C1000
D0.3

41. - E8C01

How is Forward Error Correction implemented?

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

42. - E8D06

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

SelectAnswer
AForeign language characters can be sent
BFaster transmission rate
CSome types of errors can be detected
DThe signal can overpower interfering signals

43. - E9A03

What is the radiation resistance of an antenna?

SelectAnswer
AThe value of a resistance that would dissipate the same amount of power as that radiated from an antenna
BThe resistance in the atmosphere that an antenna must overcome to be able to radiate a signal
CThe specific impedance of the antenna
DThe combined losses of the antenna elements and feed line

44. - E9B02

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

SelectAnswer
A18 dB
B24 dB
C14 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 horizontal beamwidth increases in the uphill direction
CThe main lobe takeoff angle increases in the downhill direction
DThe horizontal beamwidth decreases in the downhill 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 lower the radiation angle
CTo minimize losses
DTo minimize the Q

47. - E9E08

What is a use for a Wilkinson divider?

SelectAnswer
AIt divides the operating frequency of a transmitter signal so it can be used on a lower frequency band
BIt is used to divide power equally between two 50-ohm loads while maintaining 50-ohm input impedance
CIt is used to feed high-impedance antennas from a low-impedance source
DIt is used to feed low-impedance loads from a high-impedance source

48. - E9F01

What is the velocity factor of a transmission line?

SelectAnswer
AThe velocity of the wave in the transmission line divided by the velocity of light in a vacuum
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 index of shielding for coaxial cable

49. - E9G11

How are the wavelength scales on a Smith chart calibrated?

SelectAnswer
AIn fractions of antenna electrical frequency
BIn fractions of antenna electrical wavelength
CIn fractions of transmission line electrical frequency
DIn fractions of transmission line electrical wavelength

50. - E9H08

What is the function of a sense antenna?

SelectAnswer
AIt provides diversity reception that cancels multipath signals
BIt modifies the pattern of a DF antenna array to provide a null in one direction
CIt increases the sensitivity of a DF antenna array
DIt allows DF antennas to receive signals at different vertical angles

Figure E7-3

Figure E9-1