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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
A30 to 300 MHz
B300 kHz to 3 MHz
C300 to 3000 MHz
D3 to 30 MHz

2. - E1A07

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

SelectAnswer
A5 watts EIRP (Equivalent isotropic radiated power)
B100 watts PEP
C1 watt EIRP (Equivalent isotropic radiated power)
D50 watts PEP

3. - E1B11

What does PRB-1 require of regulations affecting amateur radio?

SelectAnswer
AAmateur radio operations must be permitted in any private residence
BReasonable accommodations of amateur radio must be made
CUse of wireless devices in a vehicle is exempt from regulation
DNo limitations may be placed on antenna size or placement

4. - E1C07

At what level below a signal's mean power level is its bandwidth determined according to FCC rules?

SelectAnswer
A26 dB
B3 dB
C23 dB
D6 dB

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. - 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. - E1F04

Which of the following geographic descriptions approximately describes "Line A"?

SelectAnswer
AA line roughly parallel to and west of the U.S. Atlantic coastline
BA line roughly parallel to and south of the border between the U.S. and Canada
CA line roughly parallel to and north of the border between the U.S. and Mexico
DA line roughly parallel to and east of the U.S. Pacific coastline

8. - E2A11

What type of antenna can be used to minimize the effects of spin modulation and Faraday rotation?

SelectAnswer
AA circularly polarized antenna
BA log-periodic dipole array
CA linearly polarized antenna
DAn isotropic antenna

9. - E2B08

What technique allows commercial analog TV receivers to be used for fast-scan TV operations on the 70 cm band?

SelectAnswer
ATransmitting on the abandoned TV channel 2
BUsing converted satellite TV dishes
CTransmitting on channels shared with cable TV
DUsing USB and demodulating the signal with a computer sound card

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
CThe often-prohibited practice of posting one's own call sign and frequency on a spotting network
DAn automatic method for rapidly zero beating or tuning to a station's frequency before calling that station

11. - E2D06

Which of the following describes a method of establishing EME contacts?

SelectAnswer
AHigh-speed CW identification to avoid fading
BJudging optimum transmission times by monitoring beacons reflected from the moon
CTime synchronous transmissions alternately from each station
DStoring and forwarding digital messages

12. - E2E03

How is the timing of FT4 contacts organized?

SelectAnswer
AIt depends on the lunar phase
BBy exchanging ACK/NAK packets
CStations take turns on alternate days
DAlternating transmissions at 7.5 second intervals

13. - E3A10

Which type of atmospheric structure can create a path for microwave propagation?

SelectAnswer
ATemperature inversion
BDust devil
CThe jet stream
DWind shear

14. - E3B11

At what time of day can sporadic E propagation occur?

SelectAnswer
AOnly in hours of darkness
BOnly around sunset
CAny time
DOnly around sunset and sunrise

15. - E3C07

Which of the following descriptors indicates the greatest solar flare intensity?

SelectAnswer
AClass B
BClass X
CClass M
DClass A

16. - E4A07

Which of the following is an advantage of using an antenna analyzer compared to an SWR bridge to measure antenna SWR?

SelectAnswer
AAntenna analyzers automatically tune your antenna for resonance
BAntenna analyzers display a time-varying representation of the modulation envelope
CAll these choices are correct
DAntenna analyzers do not need an external RF source

17. - E4B09

What is indicated if the current reading on an RF ammeter placed in series with the antenna feed line of a transmitter increases as the transmitter is tuned to resonance?

SelectAnswer
AThere is more power going into the antenna
BThere is possibly a short to ground in the feed line
CThere is an impedance mismatch between the antenna and feed line
DThe transmitter is not properly neutralized

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

19. - E4D06

What is the term for spurious signals generated by the combination of two or more signals in a non-linear device or circuit?

SelectAnswer
AAdjacent channel interference
BAmplifier desensitization
CIntermodulation
DNeutralization

20. - E4E11

What could cause local AM broadcast band signals to combine to generate spurious signals in the MF or HF bands?

SelectAnswer
AYou are receiving skywave signals from a distant station
BYour station receiver IF amplifier stage is defective
CNearby corroded metal joints are mixing and re-radiating the broadcast signals
DOne or more of the broadcast stations is transmitting an over-modulated signal

21. - E5A16

What is the resonant frequency of an RLC circuit if R is 33 ohms, L is 50 microhenries and C is 10 picofarads?

SelectAnswer
A23.5 kHz
B23.5 MHz
C7.12 MHz
D7.12 kHz

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

23. - E5C03

Which of the following represents an inductive reactance in polar coordinates?

SelectAnswer
AA positive phase angle
BA negative phase angle
CA negative magnitude
DA positive magnitude

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
B1.73
C1.414
D0.5

25. - E6A02

Which of the following semiconductor materials contains excess free electrons?

SelectAnswer
ABipolar
BN-type
CInsulated gate
DP-type

26. - E6B10

In Figure E6-2, what is the schematic symbol for a light-emitting diode?

SelectAnswer
A1
B7
C5
D6

27. - E6C09

What is a Programmable Logic Device (PLD)?

SelectAnswer
AProgrammable equipment used for testing digital logic integrated circuits
BA programmable collection of logic gates and circuits in a single integrated circuit
CA logic circuit that can be modified during use
DA type of transistor whose gain can be changed by digital logic circuits

28. - E6D03

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

SelectAnswer
AGeneration of electrical energy in the presence of light
BMechanical deformation of material by the application of a magnetic field
CMechanical deformation of material by the application of a voltage
DIncreased conductivity in the presence of light

29. - E6E12

Why are DIP through-hole package ICs not typically used at UHF and higher frequencies?

SelectAnswer
AUnsuitable for combining analog and digital signals
BToo many pins
CExcessive lead length
DEpoxy coating is conductive above 300 MHz

30. - E6F02

What happens to the conductivity of a photoconductive material when light shines on it?

SelectAnswer
AIt stays the same
BIt becomes unstable
CIt increases
DIt decreases

31. - E7A03

Which of the following can divide the frequency of a pulse train by 2?

SelectAnswer
AAn XOR gate
BA flip-flop
CA multiplexer
DAn OR gate

32. - E7B15

What is one way to prevent thermal runaway in a bipolar transistor amplifier?

SelectAnswer
AAll these choices are correct
BSelect transistors with high beta
CNeutralization
DUse a resistor in series with the emitter

33. - E7C01

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

SelectAnswer
ATwo inductors are in series between the input and output, and a capacitor is connected between the two inductors and ground
BA 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
CAn 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
DTwo capacitors are in series between the input and output, and an inductor is connected between the two capacitors and ground

34. - E7D12

What is the dropout voltage of an analog voltage regulator?

SelectAnswer
AMinimum input-to-output voltage required to maintain regulation
BMaximum that the output voltage may decrease at rated load
CMaximum output voltage drops when the input voltage is varied over its specified range
DMinimum input voltage for rated power dissipation

35. - E7E05

What circuit is added to an FM transmitter to boost the higher audio frequencies?

SelectAnswer
AA pre-emphasis network
BA heterodyne enhancer
CA de-emphasis network
DA heterodyne suppressor

36. - E7F13

What is the function of taps in a digital signal processing filter?

SelectAnswer
AProvide access for debugging software
BSelect the point at which baseband signals are generated
CTo reduce excess signal pressure levels
DProvide incremental signal delays for filter algorithms

37. - E7G01

What is the typical output impedance of an op-amp?

SelectAnswer
AVery high
B100 ohms
C1000 ohms
DVery low

38. - E7H01

What are three oscillator circuits used in amateur radio equipment?

SelectAnswer
ATaft, Pierce and negative feedback
BPierce, Fenner and Beane
CTaft, Hartley and Pierce
DColpitts, Hartley and Pierce

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
BVery high speed allows digitizing high frequencies
CAll these choices are correct
DVery low power consumption decreases frequency drift

40. - E8B02

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

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

41. - E8C06

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

SelectAnswer
A1.0 kHz
B0.3 kHz
C0.5 kHz
D0.1 Hz

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 wait until the frequency is clear
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 change frequencies
DA binary bit stream is used to shift the phase of an RF carrier very rapidly in a pseudorandom sequence

43. - E9A08

What is antenna bandwidth?

SelectAnswer
AAntenna length divided by the number of elements
BThe angle between the half-power radiation points
CThe angle formed between two imaginary lines drawn through the element ends
DThe frequency range over which an antenna satisfies a performance requirement

44. - E9B08

What is the far field of an antenna?

SelectAnswer
AThe region where the shape of the antenna pattern is independent of distance
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 radiated field strengths are constant

45. - E9C12

Which of the following describes an Extended Double Zepp antenna?

SelectAnswer
AA center-fed 1.25-wavelength antenna (two 5/8-wave elements in phase)
BA wideband vertical antenna constructed from precisely tapered aluminum tubing
CAn end-fed folded dipole antenna
DA portable antenna erected using two push support poles

46. - E9D05

What usually occurs if a Yagi antenna is designed solely for maximum forward gain?

SelectAnswer
AThe front-to-back ratio increases
BThe front-to-back ratio decreases
CThe SWR is reduced
DThe frequency response is widened over the whole frequency band

47. - E9E03

What is the name of the matching system that uses a section of transmission line connected in parallel with the feed line at or near the feed point?

SelectAnswer
AThe delta match
BThe omega match
CThe gamma match
DThe stub match

48. - E9F02

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

SelectAnswer
AThe line length
BThe center conductor resistivity
CThe termination impedance
DDielectric materials used in the line

49. - E9G09

What third family of circles is often added to a Smith chart during the process of solving problems?

SelectAnswer
AStanding wave ratio circles
BRadiation-pattern circles
CCoaxial-length circles
DAntenna-length circles

50. - E9H08

What is the function of a sense antenna?

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

Figure E6-2