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

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1. - E0A09

Which insulating material commonly used as a thermal conductor for some types of electronic devices is extremely toxic if broken or crushed and the particles are accidentally inhaled?

SelectAnswer
AUranium Hexafluoride
BBeryllium Oxide
CMica
DZinc oxide

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
C14.100 MHz
D14.349 MHz

3. - E1B05

What is the National Radio Quiet Zone?

SelectAnswer
AAn area in New Mexico surrounding the White Sands Test Area
BAn area in Florida surrounding Cape Canaveral
CAn area surrounding the National Radio Astronomy Observatory
DAn area in Puerto Rico surrounding the Arecibo Radio Telescope

4. - E1C14

How long must an operator wait after filing a notification with the Utilities Technology Council (UTC) before operating on the 2200 meter or 630 meter band?

SelectAnswer
AOperators may operate after 30 days, providing they have not been told that their station is within 1 km of PLC systems using those frequencies
BOperators may not operate until a test signal has been transmitted in coordination with the local power company
COperations may commence immediately, and may continue unless interference is reported by the UTC
DOperators must not operate until approval is received

5. - E1D07

Which HF amateur bands have frequencies authorized for space stations?

SelectAnswer
AAll HF bands
BOnly the 40, 20, 17, 15, and 10 meter bands
COnly the 40, 30, 20, 15, 12, and 10 meter bands
DOnly the 40, 20, 17, 15, 12, and 10 meter bands

6. - E1E08

To which of the following examinees may a VE not administer an examination?

SelectAnswer
AFriends of the VE
BAll these choices are correct
CRelatives of the VE as listed in the FCC rules
DEmployees of the VE

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

8. - E2A05

What do the letters in a satellite's mode designator specify?

SelectAnswer
APower limits for uplink and downlink transmissions
BThe uplink and downlink frequency ranges
CThe polarization of uplink and downlink signals
DThe location of the ground control station

9. - E2B11

What is the function of the Vertical Interval Signaling (VIS) code sent as part of an SSTV transmission?

SelectAnswer
ATo identify the SSTV mode being used
BTo provide vertical synchronization
CTo identify the call sign of the station transmitting
DTo lock the color burst oscillator in color SSTV images

10. - E2C08

Which of the following contacts may be confirmed through the U.S. QSL bureau system?

SelectAnswer
ARepeater contacts between U.S. club members
BSpecial event contacts between stations in the U.S.
CContacts between a U.S. station and a non-U.S. station
DContacts using tactical call signs

11. - E2D08

What type of packet frame is used to transmit APRS beacon data?

SelectAnswer
AConnect
BUnnumbered Information
CAcknowledgement
DDisconnect

12. - E2E13

Which of these digital modes has the fastest data throughput under clear communication conditions?

SelectAnswer
AAMTOR
B300 baud packet
CPSK31
D170 Hz shift, 45 baud RTTY

13. - E3A12

What is the cause of auroral activity?

SelectAnswer
AAn extreme low-pressure area in the polar regions
BMeteor showers concentrated in the extreme northern and southern latitudes
CThe interaction in the F2 layer between the solar wind and the Van Allen belt
DThe interaction in the E layer of charged particles from the Sun with the Earth's magnetic field

14. - E3B03

What is the best time of day for transequatorial propagation?

SelectAnswer
AMorning
BLate at night
CAfternoon or early evening
DNoon

15. - E3C07

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

SelectAnswer
AClass M
BClass A
CClass B
DClass X

16. - E4A05

What is the purpose of the prescaler function on a frequency counter?

SelectAnswer
AIt divides a higher frequency signal so a low-frequency counter can display the input frequency
BIt amplifies low-level signals for more accurate counting
CIt prevents oscillation in a low-frequency counter circuit
DIt multiplies a higher frequency signal so a low-frequency counter can display the operating frequency

17. - E4B10

Which of the following methods measures intermodulation distortion in an SSB transmitter?

SelectAnswer
AModulate the transmitter using two RF signals having harmonically related frequencies and observe the RF output with a logic analyzer
BModulate the transmitter using two RF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer
CModulate the transmitter using two AF signals having harmonically related frequencies and observe the RF output with a peak reading wattmeter
DModulate the transmitter using two AF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer

18. - E4C03

What is the term for the suppression in an FM receiver of one signal by another stronger signal on the same frequency?

SelectAnswer
ACross-modulation interference
BFrequency discrimination
CDesensitization
DCapture effect

19. - E4D09

What is the purpose of the preselector in a communications receiver?

SelectAnswer
ATo provide a range of AGC time constants
BTo increase rejection of signals outside the desired band
CTo allow selection of the optimum RF amplifier device
DTo store often-used frequencies

20. - E4E05

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

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

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

22. - E5B06

What is susceptance?

SelectAnswer
AThe magnetic impedance of a circuit
BA measure of the efficiency of a transformer
CThe ratio of magnetic field to electric field
DThe imaginary part of admittance

23. - E5C11

Which point in Figure E5-1 best represents the impedance of a series circuit consisting of a 300-ohm resistor and an 18-microhenry inductor at 3.505 MHz?

SelectAnswer
APoint 7
BPoint 8
CPoint 1
DPoint 3

24. - E5D11

What is the power factor of an RL circuit having a 60-degree phase angle between the voltage and the current?

SelectAnswer
A1.73
B1.414
C0.5
D0.866

25. - E6A02

Which of the following semiconductor materials contains excess free electrons?

SelectAnswer
AN-type
BBipolar
CInsulated gate
DP-type

26. - E6B02

What is an important characteristic of a Schottky diode as compared to an ordinary silicon diode when used as a power supply rectifier?

SelectAnswer
AMore constant reverse avalanche voltage
BMuch higher reverse voltage breakdown
CLess forward voltage drop
DLonger carrier retention time

27. - E6C07

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

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

28. - E6D08

What is one reason for using powdered-iron cores rather than ferrite cores in an inductor?

SelectAnswer
APowdered-iron cores generally maintain their characteristics at higher currents
BPowdered-iron cores generally have greater initial permeability
CPowdered-iron cores generally require fewer turns to produce a given inductance
DPowdered-iron cores use smaller diameter wire for the same inductance

29. - E6E02

Which of the following device packages is a through-hole type?

SelectAnswer
ADIP
BBall grid array
CSOT
DPLCC

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. - E7A05

Which of the following is a circuit that continuously alternates between two states without an external clock?

SelectAnswer
AT flip-flop
BAstable multivibrator
CJ-K flip-flop
DMonostable multivibrator

32. - E7B12

What type of amplifier circuit is shown in Figure E7-1?

SelectAnswer
ACommon emitter
BCommon collector
CCommon base
DEmitter follower

33. - E7C08

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

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

34. - E7D06

What is the purpose of Q1 in the circuit shown in Figure E7-2?

SelectAnswer
AIt provides negative feedback to improve regulation
BIt provides a constant load for the voltage source
CIt controls the current supplied to the load
DIt provides D1 with current

35. - E7E10

How does a diode envelope detector function?

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

36. - E7F12

Which of the following is an advantage of a Finite Impulse Response (FIR) filter vs an Infinite Impulse Response (IIR) digital filter?

SelectAnswer
AFIR filters can delay all frequency components of the signal by the same amount
BFIR filters are easier to implement for a given set of passband rolloff requirements
CFIR filters can respond faster to impulses
DAll these choices are correct

37. - E7G12

What is an operational amplifier?

SelectAnswer
AA high-gain, direct-coupled differential amplifier with very high input impedance and very low output impedance
BAn amplifier used to increase the average output of frequency modulated amateur signals to the legal limit
CA digital audio amplifier whose characteristics are determined by components external to the amplifier
DA RF amplifier used in the UHF and microwave regions

38. - E7H04

How is positive feedback supplied in a Colpitts oscillator?

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

39. - E8A09

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

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

40. - E8B01

What is the modulation index of an FM signal?

SelectAnswer
AThe ratio of frequency deviation to modulating signal frequency
BThe type of modulation used by the transmitter
CThe ratio of modulating signal amplitude to frequency deviation
DThe bandwidth of the transmitted signal divided by the modulating signal frequency

41. - E8C11

What is the relationship between symbol rate and baud?

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

42. - E8D06

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

SelectAnswer
AForeign language characters can be sent
BSome types of errors can be detected
CThe signal can overpower interfering signals
DFaster transmission rate

43. - E9A04

Which of the following factors affect the feed point impedance of an antenna?

SelectAnswer
ATransmission line length
BAntenna height
CThe input power level
DThe settings of an antenna tuner at the transmitter

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. - E9C05

Which of the following is a type of OCFD antenna?

SelectAnswer
AA multiband dipole antenna using one-way circular polarization for frequency diversity
BA dipole fed approximately 1/3 the way from one end with a 4:1 balun to provide multiband operation
CA folded dipole center-fed with 300-ohm transmission line
DA remotely tunable dipole antenna using orthogonally controlled frequency diversity

46. - E9D08

What happens as the Q of an antenna increases?

SelectAnswer
ASWR bandwidth decreases
BGain is reduced
CSWR bandwidth increases
DMore common-mode current is present on the feed line

47. - E9E02

What is the name of an antenna matching system that matches an unbalanced feed line to an antenna by feeding the driven element both at the center of the element and at a fraction of a wavelength to one side of center?

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

48. - E9F04

What impedance does a 1/2-wavelength transmission line present to a generator when the line is shorted at the far end?

SelectAnswer
AThe same as the characteristic impedance of the line
BVery high impedance
CVery low impedance
DThe same as the output impedance of the generator

49. - E9G11

How are the wavelength scales on a Smith chart calibrated?

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

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

Figure E5-1

Figure E7-1

Figure E7-2