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

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1. - E0A05

What is one of the potential hazards of operating in the amateur radio microwave bands?

SelectAnswer
AMicrowaves are ionizing radiation
BThe extremely high frequency energy can damage the joints of antenna structures
CThe high gain antennas commonly used can result in high exposure levels
DMicrowaves often travel long distances by ionospheric reflection

2. - E1A04

With your transceiver displaying the carrier frequency of phone signals, you hear a DX station calling CQ on 3.601 MHz LSB. Is it legal to return the call using lower sideband on the same frequency?

SelectAnswer
ANo, U.S. stations are not permitted to use phone emissions below 3.610 MHz
BYes, because the displayed frequency is within the 75 meter phone band segment
CNo, the sideband will extend beyond the edge of the phone band segment
DYes, because the DX station initiated the contact

3. - E1B11

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

SelectAnswer
AReasonable accommodations of amateur radio must be made
BUse of wireless devices in a vehicle is exempt from regulation
CNo limitations may be placed on antenna size or placement
DAmateur radio operations must be permitted in any private residence

4. - E1C11

Which of the following operating arrangements allows an FCC-licensed U.S. citizen to operate in many European countries, and alien amateurs from many European countries to operate in the U.S.?

SelectAnswer
AITU reciprocal license
BCEPT agreement
CAll these choices are correct
DIARP agreement

5. - E1D01

What is the definition of telemetry?

SelectAnswer
AOne-way transmission of measurements at a distance from the measuring instrument
BTwo-way transmissions in excess of 1000 feet
COne-way transmission that initiates, modifies, or terminates the functions of a device at a distance
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 ARRL
BThe VECs
CThe VEs
DThe FCC

7. - E1F04

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

SelectAnswer
AA line roughly parallel to and south of the border between the U.S. and Canada
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 west of the U.S. Atlantic coastline

8. - E2A13

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

SelectAnswer
AMulti-satellite relaying
BDigipeating
CNode hopping
DStore-and-forward

9. - E2B02

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

SelectAnswer
A30
B1080
C525
D60

10. - E2C12

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

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

11. - E2D03

Which of the following digital modes is especially useful for EME communications?

SelectAnswer
APACTOR III
BMSK144
CJT65
DOlivia

12. - E2E05

Which of these digital modes does not support keyboard-to-keyboard operation?

SelectAnswer
ARTTY
BMFSK
CPSK31
DPACTOR

13. - E3A13

Which of these emission modes is best for auroral propagation?

SelectAnswer
ARTTY
BSSB
CCW
DFM

14. - E3B07

What happens to linearly polarized radio waves that split into ordinary and extraordinary waves in the ionosphere?

SelectAnswer
AThey become elliptically polarized
BThey are bent toward the magnetic poles
CThey become depolarized
DThey become phase locked

15. - E3C07

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

SelectAnswer
AClass B
BClass M
CClass A
DClass X

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 analyzer near the antenna base
DLoosely couple the antenna and a dummy load to the analyzer

17. - E4B04

Which S parameter represents input port return loss or reflection coefficient (equivalent to VSWR)?

SelectAnswer
AS22
BS21
CS11
DS12

18. - E4C05

What does a receiver noise floor of -174 dBm represent?

SelectAnswer
AThe theoretical noise in a 1 Hz bandwidth at the input of a perfect receiver at room temperature
BThe galactic noise contribution to minimum detectable signal
CThe noise figure of a 1 Hz bandwidth receiver
DThe minimum detectable signal as a function of receive frequency

19. - E4D10

What does a third-order intercept level of 40 dBm mean with respect to receiver performance?

SelectAnswer
AA pair of 40 dBm input signals will theoretically generate a third-order intermodulation product that has the same output amplitude as either of the input signals
BA pair of 1 mW input signals will produce a third-order intermodulation product that is 40 dB stronger than the input signal
CSignals less than 40 dBm will not generate audible third-order intermodulation products
DThe receiver can tolerate signals up to 40 dB above the noise floor without producing third-order intermodulation products

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
BOne or more of the broadcast stations is transmitting an over-modulated signal
CYour station receiver IF amplifier stage is defective
DNearby corroded metal joints are mixing and re-radiating the broadcast signals

21. - E5A01

What can cause the voltage across reactances in a series RLC circuit to be higher than the voltage applied to the entire circuit?

SelectAnswer
AConductance
BResistance
CResonance
DCapacitance

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 leads current by 90 degrees
CVoltage and current are 180 degrees out of phase
DCurrent leads voltage by 90 degrees

23. - E5C04

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

SelectAnswer
AFaraday grid
BMaidenhead grid
CElliptical coordinates
DRectangular coordinates

24. - E5D15

What is the power factor of an RL circuit having a 45-degree phase angle between the voltage and the current?

SelectAnswer
A0.5
B0.866
C0.707
D1.0

25. - E6A07

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

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

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 VHF/UHF mixer or detector
CAs a rectifier in high current power supplies
DAs a constant voltage reference in a power supply

27. - E6C03

What is tri-state logic?

SelectAnswer
AProprietary logic devices manufactured by Tri-State Devices
BLogic devices with 0, 1, and high-impedance output states
CLogic devices that utilize ternary math
DLow-power logic devices designed to operate at 3 volts

28. - E6D03

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

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

29. - E6E01

Why is gallium arsenide (GaAs) useful for semiconductor devices operating at UHF and higher frequencies?

SelectAnswer
AHigher noise figures
BLower transconductance
CLower junction voltage drop
DHigher electron mobility

30. - E6F11

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

SelectAnswer
A12 V
B0.5 V
C0.1 V
D1.5 V

31. - E7A02

What is the function of a decade counter?

SelectAnswer
AIt produces 10 output pulses for every input pulse
BIt decodes a binary number for display on a seven-segment LED display
CIt decodes a decimal number for display on a seven-segment LED display
DIt produces one output pulse for every 10 input pulses

32. - E7B15

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

SelectAnswer
ANeutralization
BUse a resistor in series with the emitter
CAll these choices are correct
DSelect transistors with high beta

33. - E7C12

What is one advantage of a Pi-matching network over an L-matching network consisting of a single inductor and a single capacitor?

SelectAnswer
AL-networks cannot perform impedance transformation
BThe Q of Pi-networks can be controlled
CPi-networks provide balanced input and output
DPi-networks are more stable

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

35. - E7E11

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

SelectAnswer
ADiscriminator
BPhase detector
CPhase comparator
DProduct detector

36. - E7F04

What is a common method of generating an SSB signal using digital signal processing?

SelectAnswer
AVarying quartz crystal characteristics emulated in digital form
BA frequency synthesizer removes the unwanted sidebands
CSignals are combined in quadrature phase relationship
DMixing products are converted to voltages and subtracted by adder circuits

37. - E7G07

What magnitude of voltage gain can be expected from the circuit in Figure E73 when R1 is 10 ohms and RF is 470 ohms?

SelectAnswer
A94
B47
C24
D0.21

38. - E7H07

How can an oscillator's microphonic responses be reduced?

SelectAnswer
AReduce noise on the oscillator's power supply
BUse NP0 capacitors
CMechanically isolate the oscillator circuitry from its enclosure
DIncrease the bias voltage

39. - E8A11

Which of the following is a measure of the quality of an analog-to-digital converter?

SelectAnswer
ATotal harmonic distortion
BPeak envelope power
CReciprocal mixing
DPower factor

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. - E8C01

How is Forward Error Correction implemented?

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

42. - E8D05

What is the most common method of reducing key clicks?

SelectAnswer
ALow-pass filters at the transmitter output
BIncrease keying waveform rise and fall times
CHigh-pass filters at the transmitter output
DReduce keying waveform rise and fall times

43. - E9A01

What is an isotropic antenna?

SelectAnswer
AA horizontally polarized antenna used to compare Yagi antennas
BA grounded antenna used to measure Earth conductivity
CA theoretical, omnidirectional antenna used as a reference for antenna gain
DA spacecraft antenna used to direct signals toward Earth

44. - E9B01

In the antenna radiation pattern shown in Figure E9-1, what is the beamwidth?

SelectAnswer
A30 degrees
B50 degrees
C75 degrees
D25 degrees

45. - E9C12

Which of the following describes an Extended Double Zepp antenna?

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

46. - E9D01

How much does the gain of an ideal parabolic dish antenna change when the operating frequency is doubled?

SelectAnswer
A4 dB
B2 dB
C6 dB
D3 dB

47. - E9E08

What is a use for a Wilkinson divider?

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

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 low impedance
CVery high impedance
DThe same as the output impedance of the generator

49. - E9G02

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

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

50. - E9H11

What feature of a cardioid pattern antenna makes it useful for direction finding?

SelectAnswer
AA very sharp peak
BHigh radiation angle
CA very sharp single null
DBroadband response

Figure E9-1