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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
BReduce RFI to telephones and home entertainment systems
CReduce received noise
DLightning protection

2. - E1A01

Which of the following carrier frequencies is illegal for LSB AFSK emissions on the 17 meter band RTTY and data segment of 18.068 to 18.110 MHz?

SelectAnswer
A18.110 MHz
B18.068 MHz
C18.100 MHz
D18.107 MHz

3. - E1B01

Which of the following constitutes a spurious emission?

SelectAnswer
AAn emission outside the signal's necessary bandwidth that can be reduced or eliminated without affecting the information transmitted
BAny transmitted signal that unintentionally interferes with another licensed radio station
CAn amateur station transmission made without the proper call sign identification
DA signal transmitted to prevent its detection by any station other than the intended recipient

4. - E1C03

How do the control operator responsibilities of a station under automatic control differ from one under local control?

SelectAnswer
AUnder automatic control there is no control operator
BUnder local control there is no control operator
CUnder automatic control the control operator is not required to be present at the control point
DUnder local control a control operator is not required to be present at a control point

5. - E1D08

Which VHF amateur bands have frequencies authorized for space stations?

SelectAnswer
A6 meters, 2 meters, and 1.25 meters
B6 meters and 2 meters
C2 meters and 1.25 meters
D2 meters

6. - E1E06

Who is responsible for the proper conduct and necessary supervision during an amateur operator license examination session?

SelectAnswer
AThe VE session manager
BEach administering VE
CThe FCC
DThe VEC coordinating the session

7. - E1F10

Who may be the control operator of an auxiliary station?

SelectAnswer
AAny licensed amateur operator
BOnly Technician, General, Advanced or Amateur Extra Class operators
COnly General, Advanced or Amateur Extra Class operators
DOnly Amateur Extra Class operators

8. - E2A10

What type of satellite appears to stay in one position in the sky?

SelectAnswer
AGeomagnetic
BHEO
CGeostationary
DLEO

9. - E2B08

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

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

10. - E2C12

What technique do individual nodes use to form a mesh network?

SelectAnswer
AForward error correction and Viterbi codes
BDiscovery and link establishment protocols
CActing as store-and-forward digipeaters
DCustom code plugs for the local trunking systems

11. - E2D04

What technology is used to track, in real time, balloons carrying amateur radio transmitters?

SelectAnswer
AUltrasonics
BBandwidth compressed LORAN
CAPRS
DDoppler shift of beacon signals

12. - E2E07

Which of the following is a possible reason that attempts to initiate contact with a digital station on a clear frequency are unsuccessful?

SelectAnswer
AAll these choices are correct
BAnother station you are unable to hear is using the frequency
CThe protocol version you are using is not supported by the digital station
DYour transmit frequency is incorrect

13. - E3A11

What is a typical range for tropospheric propagation of microwave signals?

SelectAnswer
A10 miles to 50 miles
B1200 miles
C100 miles to 300 miles
D2500 miles

14. - E3B03

What is the best time of day for transequatorial propagation?

SelectAnswer
ANoon
BLate at night
CAfternoon or early evening
DMorning

15. - E3C01

What does the radio communication term "ray tracing" describe?

SelectAnswer
AModeling a radio wave's path through the ionosphere
BThe process in which an electronic display presents a pattern
CDetermining the radiation pattern from an array of antennas
DEvaluating high voltage sources for x-rays

16. - E4A10

Which of the following displays multiple digital signal states simultaneously?

SelectAnswer
ANetwork analyzer
BBit error rate tester
CModulation monitor
DLogic analyzer

17. - E4B11

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

SelectAnswer
AOutput impedance
BAll these choices are correct
CInput impedance
DReflection coefficient

18. - E4C07

What does the MDS of a receiver represent?

SelectAnswer
AThe minimum discernible signal
BThe multiplex distortion stability
CThe maximum detectable spectrum
DThe meter display sensitivity

19. - E4D11

Why are odd-order intermodulation products, created within a receiver, of particular interest compared to other products?

SelectAnswer
AOdd-order products of two signals in the band of interest are also likely to be within the band
BOdd-order intermodulation produces three products for every input signal within the band of interest
COdd-order products are an indication of poor image rejection
DOdd-order products overload the IF filters

20. - E4E01

What problem can occur when using an automatic notch filter (ANF) to remove interfering carriers while receiving CW signals?

SelectAnswer
ARemoval of the CW signal as well as the interfering carrier
BReceived CW signals will appear to be modulated at the DSP clock frequency
CAny nearby signal passing through the DSP system will overwhelm the desired signal
DRinging in the DSP filter will completely remove the spaces between the CW characters

21. - E5A10

How is the Q of an RLC series resonant circuit calculated?

SelectAnswer
AReactance of the inductance multiplied by the reactance of the capacitance
BResistance divided by the reactance of either the inductance or capacitance
CReactance of either the inductance or capacitance multiplied by the resistance
DReactance of either the inductance or capacitance divided by the resistance

22. - E5B10

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

SelectAnswer
AVoltage and current are in phase
BVoltage and current are 180 degrees out of phase
CCurrent leads voltage by 90 degrees
DVoltage leads current by 90 degrees

23. - E5C04

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

SelectAnswer
ARectangular coordinates
BMaidenhead grid
CElliptical coordinates
DFaraday grid

24. - E5D06

In what direction is the magnetic field oriented about a conductor in relation to the direction of electron flow?

SelectAnswer
AIn a circle around the conductor
BIn the same direction as the current
CIn all directions; omni-directional
DIn a direction opposite to the current

25. - E6A01

In what application is gallium arsenide used as a semiconductor material?

SelectAnswer
AIn microwave circuits
BIn high-current rectifier circuits
CIn high-power audio circuits
DIn very low-frequency RF circuits

26. - E6B06

Which of the following is a common use of a Schottky diode?

SelectAnswer
AAs a variable capacitance in an automatic frequency control circuit
BAs a rectifier in high current power supplies
CAs a constant voltage reference in a power supply
DAs a VHF/UHF mixer or detector

27. - E6C02

What happens when the level of a comparator's input signal crosses the threshold?

SelectAnswer
AThe feedback loop becomes unstable
BThe comparator changes its output state
CThe comparator enters latch-up
DThe IC input can be damaged

28. - E6D07

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

SelectAnswer
ADirect current
BStabilizing current
CMagnetizing current
DExcitation current

29. - E6E10

What advantage does surface-mount technology offer at RF compared to using through-hole components?

SelectAnswer
ASmaller circuit area
BAll these choices are correct
CComponents have less parasitic inductance and capacitance
DShorter circuit-board traces

30. - E6F03

What is the most common configuration of an optoisolator or optocoupler?

SelectAnswer
AA lens and a photomultiplier
BA frequency modulated helium-neon laser
CAn amplitude modulated helium-neon laser
DAn LED and a phototransistor

31. - E7A03

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

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

32. - E7B07

Which of the following is a likely result when a Class C amplifier is used to amplify a single-sideband phone signal?

SelectAnswer
ASignal inversion
BReduced intermodulation products
CSignal distortion and excessive bandwidth
DIncreased overall intelligibility

33. - E7C04

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

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

34. - E7D15

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

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

35. - E7E02

What is the function of a reactance modulator?

SelectAnswer
ATo produce PM signals by using an electrically variable resistance
BTo produce AM signals by using an electrically variable resistance
CTo produce PM or FM signals by using an electrically variable inductance or capacitance
DTo produce AM signals by using an electrically variable inductance or capacitance

36. - E7F02

What kind of digital signal processing audio filter is used to remove unwanted noise from a received SSB signal?

SelectAnswer
AA Hilbert-transform filter
BAn adaptive filter
CA phase-inverting filter
DA crystal-lattice filter

37. - E7G06

What is the gain-bandwidth of an operational amplifier?

SelectAnswer
AThe frequency at which the open-loop gain of the amplifier equals one
BThe gain of the amplifier at a filter's cutoff frequency
CThe frequency at which the amplifier's offset voltage is zero
DThe maximum frequency for a filter circuit using that type of amplifier

38. - E7H04

How is positive feedback supplied in a Colpitts oscillator?

SelectAnswer
AThrough a tapped coil
BThrough link coupling
CThrough a capacitive divider
DThrough a neutralizing capacitor

39. - E8A09

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

SelectAnswer
A256
B8
C256 divided by the gain of the input amplifier
D8 multiplied by the gain of the input amplifier

40. - E8B04

What is the modulation index of an FM-phone signal having a maximum carrier deviation of plus or minus 6 kHz when modulated with a 2 kHz modulating frequency?

SelectAnswer
A2000
B6000
C3
D1/3

41. - E8C06

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

SelectAnswer
A0.3 kHz
B0.5 kHz
C1.0 kHz
D0.1 Hz

42. - E8D02

What spread spectrum communications technique uses a high-speed binary bit stream to shift the phase of an RF carrier?

SelectAnswer
ADirect sequence
BPhase compandored spread spectrum
CBinary phase-shift keying
DFrequency hopping

43. - E9A13

What term describes station output, taking into account all gains and losses?

SelectAnswer
AHalf-power bandwidth
BApparent power
CPower factor
DEffective radiated power

44. - E9B03

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

SelectAnswer
A14 dB
B18 dB
C24 dB
D12 dB

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 portable antenna erected using two push support poles
CAn end-fed folded dipole antenna
DA wideband vertical antenna constructed from precisely tapered aluminum tubing

46. - E9D02

How can linearly polarized Yagi antennas be used to produce circular polarization?

SelectAnswer
AArrange two Yagis collinear to each other with the driven elements fed 180 degrees out of phase
BStack two Yagis fed 90 degrees out of phase to form an array with the respective elements in parallel planes
CArrange two Yagis perpendicular to each other with the driven elements at the same point on the boom fed 90 degrees out of phase
DStack two Yagis fed in phase to form an array with the respective elements in parallel planes

47. - E9E11

What is the primary purpose of phasing lines when used with an antenna having multiple driven elements?

SelectAnswer
AIt ensures that each driven element operates in concert with the others to create the desired antenna pattern
BIt prevents reflected power from traveling back down the feed line and causing harmonic radiation from the transmitter
CIt creates a low-angle radiation pattern
DIt allows single-band antennas to operate on other bands

48. - E9F06

What is the approximate physical length of an air-insulated, parallel conductor transmission line that is electrically 1/2 wavelength long at 14.10 MHz?

SelectAnswer
A13.3 meters
B10.6 meters
C7.0 meters
D8.5 meters

49. - E9G09

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

SelectAnswer
ACoaxial-length circles
BStanding wave ratio circles
CAntenna-length circles
DRadiation-pattern circles

50. - E9H02

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

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

Figure E9-1