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

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1. - E0A11

Which of the following injuries can result from using high-power UHF or microwave transmitters?

SelectAnswer
AHearing loss caused by high voltage corona discharge
BIngestion of ozone gas from the cooling system
CBlood clotting from the intense magnetic field
DLocalized heating of the body from RF exposure in excess of the MPE limits

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

3. - E1B04

What must be done before placing an amateur station within an officially designated wilderness area or wildlife preserve, or an area listed in the National Register of Historic Places?

SelectAnswer
AA proposal must be submitted to the National Park Service
BA form FSD-15 must be submitted to the Department of the Interior
CA letter of intent must be filed with the Environmental Protection Agency
DAn Environmental Assessment must be submitted to the FCC

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 53 dB below
CAt least 73 dB below
DAt least 63 dB below

5. - E1D08

Which VHF amateur bands have frequencies authorized for space stations?

SelectAnswer
A6 meters and 2 meters
B2 meters
C2 meters and 1.25 meters
D6 meters, 2 meters, and 1.25 meters

6. - E1E04

Which of the following best describes the Volunteer Examiner accreditation process?

SelectAnswer
AThe prospective VE obtains accreditation from the FCC
BEach General, Advanced and Amateur Extra Class operator is automatically accredited as a VE when the license is granted
CThe procedure by which a VEC confirms that the VE applicant meets FCC requirements to serve as an examiner
DThe amateur operator applying must pass a VE examination administered by the FCC Enforcement Bureau

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 allow regular operation on Land Mobile channels
CTo provide for experimental amateur communications
DTo provide temporary operation while awaiting normal licensing

8. - E2A13

Which of the following techniques is normally used by low Earth orbiting digital satellites to relay messages around the world?

SelectAnswer
AStore-and-forward
BDigipeating
CMulti-satellite relaying
DNode hopping

9. - E2B02

How many horizontal lines make up a fast-scan (NTSC) television frame?

SelectAnswer
A525
B1080
C60
D30

10. - E2C03

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

SelectAnswer
A6 meters
B30 meters
C33 centimeters
D2 meters

11. - E2D07

What digital protocol is used by APRS?

SelectAnswer
AAMTOR
B802.11
CPACTOR
DAX.25

12. - E2E13

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

SelectAnswer
A300 baud packet
BAMTOR
C170 Hz shift, 45 baud RTTY
DPSK31

13. - E3A12

What is the cause of auroral activity?

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

14. - E3B11

At what time of day can sporadic E propagation occur?

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

15. - E3C10

What does the 304A solar parameter measure?

SelectAnswer
AThe ratio of x-ray flux to radio flux, correlated to sunspot number
BThe solar wind velocity at 304 degrees from the solar equator, correlated to solar activity
CThe solar emission at 304 GHz, correlated to x-ray flare levels
DUV emissions at 304 angstroms, correlated to the solar flux index

16. - E4A04

How is the compensation of an oscilloscope probe typically adjusted?

SelectAnswer
AA frequency standard is displayed and the probe is adjusted until the deflection time is accurate
BA DC voltage standard is displayed and the probe is adjusted until the displayed voltage is accurate
CA high frequency sine wave is displayed and the probe is adjusted for maximum amplitude
DA square wave is displayed and the probe is adjusted until the horizontal portions of the displayed wave are as nearly flat as possible

17. - E4B06

How much power is being absorbed by the load when a directional power meter connected between a transmitter and a terminating load reads 100 watts forward power and 25 watts reflected power?

SelectAnswer
A100 watts
B125 watts
C75 watts
D25 watts

18. - E4C06

A CW receiver with the AGC off has an equivalent input noise power density of -174 dBm/Hz. What would be the level of an unmodulated carrier input to this receiver that would yield an audio output SNR of 0 dB in a 400 Hz noise bandwidth?

SelectAnswer
A-148 dBm
B-174 dBm
C-155 dBm
D-164 dBm

19. - E4D05

What transmitter frequencies would cause an intermodulation-product signal in a receiver tuned to 146.70 MHz when a nearby station transmits on 146.52 MHz?

SelectAnswer
A173.35 MHz and 139.40 MHz
B146.10 MHz and 147.30 MHz
C146.34 MHz and 146.61 MHz
D146.88 MHz and 146.34 MHz

20. - E4E07

Which of the following can cause shielded cables to radiate or receive interference?

SelectAnswer
AUse of braided shielding material
BLow inductance ground connections at both ends of the shield
CTying all ground connections to a common point resulting in differential-mode currents in the shield
DCommon-mode currents on the shield and conductors

21. - E5A10

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

SelectAnswer
AResistance divided by the reactance of either the inductance or capacitance
BReactance of either the inductance or capacitance multiplied by the resistance
CReactance of the inductance multiplied by the reactance of the capacitance
DReactance of either the inductance or capacitance divided by the resistance

22. - E5B07

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 500 ohms, R is 1 kilohm, and XL is 250 ohms?

SelectAnswer
A68.2 degrees with the voltage leading the current
B14.0 degrees with the voltage leading the current
C14.0 degrees with the voltage lagging the current
D68.2 degrees with the voltage lagging the current

23. - E5C09

When using rectangular coordinates to graph the impedance of a circuit, what do the axes represent?

SelectAnswer
AThe X axis represents the magnitude and the Y axis represents the phase angle
BThe X axis represents the resistive component and the Y axis represents the reactive component
CThe X axis represents the phase angle and the Y axis represents the magnitude
DThe X axis represents the reactive component and the Y axis represents the resistive component

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. - E6A07

Which of the following indicates that a silicon NPN junction transistor is biased on?

SelectAnswer
ABase-to-emitter resistance of approximately 6 to 7 ohms
BBase-to-emitter voltage of approximately 6 to 7 volts
CBase-to-emitter resistance of approximately 0.6 to 0.7 ohms
DBase-to-emitter voltage of approximately 0.6 to 0.7 volts

26. - E6B05

What characteristic of a PIN diode makes it useful as an RF switch?

SelectAnswer
AExtremely high reverse breakdown voltage
BReverse bias controls its forward voltage drop
CAbility to dissipate large amounts of power
DLow junction capacitance

27. - E6C07

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

SelectAnswer
AA resistor in a keying circuit used to reduce key clicks
BA resistor that ensures that an oscillator frequency does not drift
CA resistor connected to an op-amp output that prevents signals from exceeding the power supply voltage
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. - E6D02

What is the equivalent circuit of a quartz crystal?

SelectAnswer
AMotional capacitance, motional inductance, and loss resistance in series, all in parallel with a shunt capacitor representing electrode and stray capacitance
BMotional inductance and loss resistance in series, paralleled with motional capacitance and a capacitor representing electrode and stray capacitance
CMotional capacitance, motional inductance, loss resistance, and a capacitor representing electrode and stray capacitance all in parallel
DMotional capacitance, motional inductance, loss resistance, and a capacitor representing electrode and stray capacitance all in series

29. - E6E12

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

SelectAnswer
AToo many pins
BEpoxy coating is conductive above 300 MHz
CUnsuitable for combining analog and digital signals
DExcessive lead length

30. - E6F08

Why are optoisolators often used in conjunction with solid-state circuits when switching 120 VAC?

SelectAnswer
AOptoisolators provide a low impedance link between a control circuit and a power circuit
BOptoisolators eliminate the effects of reflected light in the control circuit
COptoisolators provide a very high degree of electrical isolation between a control circuit and the circuit being switched
DOptoisolators provide impedance matching between the control circuit and power circuit

31. - E7A11

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

SelectAnswer
AAssertive Logic
BNegative logic
CReverse Logic
DPositive Logic

32. - E7B04

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

SelectAnswer
AWhere the load line intersects the voltage axis
BAt a point where the bias resistor equals the load resistor
CAt a point where the load line intersects the zero bias current curve
DApproximately halfway between saturation and cutoff

33. - E7C03

What advantage does a series-L Pi-L-network have over a series-L Pi-network for impedance matching between the final amplifier of a vacuum-tube transmitter and an antenna?

SelectAnswer
ADoes not require a capacitor
BHigher efficiency
CGreater harmonic suppression
DGreater transformation range

34. - E7D07

What is the purpose of C2 in the circuit shown in Figure E7-2?

SelectAnswer
ATo self-resonate at the hum frequency
BTo provide fixed DC bias for Q1
CIt is a brute force filter for the output
DIt bypasses rectifier output ripple around D1

35. - E7E11

Which type of detector circuit is used for demodulating SSB signals?

SelectAnswer
APhase detector
BProduct detector
CPhase comparator
DDiscriminator

36. - E7F02

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

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

37. - E7G10

What absolute voltage gain can be expected from the circuit in Figure E7-3 when R1 is 1800 ohms and RF is 68 kilohms?

SelectAnswer
A1
B0.03
C76
D38

38. - E7H01

What are three oscillator circuits used in amateur radio equipment?

SelectAnswer
AColpitts, Hartley and Pierce
BPierce, Fenner and Beane
CTaft, Pierce and negative feedback
DTaft, Hartley and Pierce

39. - E8A09

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

SelectAnswer
A256
B8
C8 multiplied by the gain of the input amplifier
D256 divided 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
C1/3
D3

41. - E8C08

How does ARQ accomplish error correction?

SelectAnswer
ASpecial binary codes provide automatic correction
BIf errors are detected, a retransmission is requested
CIf errors are detected, redundant data is substituted
DSpecial polynomial codes provide automatic correction

42. - E8D04

What is the primary effect of extremely short rise or fall time on a CW signal?

SelectAnswer
ALimits data speed
BThe generation of RF harmonics
CThe generation of key clicks
DMore difficult to copy

43. - E9A06

What is the effective radiated power relative to a dipole of a repeater station with 200 watts transmitter power output, 4 dB feed line loss, 3.2 dB duplexer loss, 0.8 dB circulator loss, and 10 dBd antenna gain?

SelectAnswer
A317 watts
B300 watts
C126 watts
D2000 watts

44. - E9B06

What is the elevation angle of peak response in the antenna radiation pattern shown in Figure E9-2?

SelectAnswer
A45 degrees
B75 degrees
C25 degrees
D7.5 degrees

45. - E9C03

What is the radiation pattern of two 1/4-wavelength vertical antennas spaced 1/2-wavelength apart and fed in phase?

SelectAnswer
AA Figure-8 broadside to the axis of the array
BOmni-directional
CCardioid
DA Figure-8 end-fire along the axis of the array

46. - E9D06

What happens to the SWR bandwidth when one or more loading coils are used to resonate an electrically short antenna?

SelectAnswer
AIt is decreased
BIt is unchanged if the loading coil is located at the feed point
CIt is increased
DIt is unchanged if the loading coil is located at a voltage maximum point

47. - E9E04

What is the purpose of the series capacitor in a gamma-type antenna matching network?

SelectAnswer
ATo provide DC isolation between the feed line and the antenna
BTo provide a rejection notch that prevents the radiation of harmonics
CTo transform the antenna impedance to a higher value
DTo cancel the inductive reactance of the matching network

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

49. - E9G02

What type of coordinate system is used in a Smith chart?

SelectAnswer
AResistance circles and reactance arcs
BVoltage lines and current chords
CVoltage circles and current arcs
DResistance lines and reactance chords

50. - E9H06

What is the triangulation method of direction finding?

SelectAnswer
AA fixed receiving station plots three headings to the signal source
BA fixed receiving station uses three different antennas to plot the location of the signal source
CAntenna headings from several different receiving locations are used to locate the signal source
DThe geometric angles of sky waves from the source are used to determine its position

Figure E7-2

Figure E7-3

Figure E9-2