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?

Select	Answer
A	Microwaves often travel long distances by ionospheric reflection
B	The extremely high frequency energy can damage the joints of antenna structures
C	The high gain antennas commonly used can result in high exposure levels
D	Microwaves are ionizing radiation

2. - E1A14

Except in some parts of Alaska, what is the maximum power permitted on the 630 meter band?

Select	Answer
A	100 watts PEP
B	5 watts EIRP
C	50 watts PEP
D	1 watt EIRP

3. - E1B10

What frequencies are authorized to an amateur station operating under RACES rules?

Select	Answer
A	All amateur service frequencies authorized to the control operator
B	Specific local government channels
C	Specific segments in the amateur service MF, HF, VHF and UHF bands
D	Military Auxiliary Radio System (MARS) channels

4. - E1C02

Which of the following types of communications may be transmitted to amateur stations in foreign countries?

Select	Answer
A	All these choices are correct
B	Messages intended for users of the maritime satellite service
C	Business-related messages for non-profit organizations
D	Communications incidental to the purpose of the amateur service and remarks of a personal nature

5. - E1D03

What is a space telecommand station?

Select	Answer
A	An amateur station located in a satellite or a balloon more than 50 kilometers above the surface of the Earth
B	An amateur station that transmits communications to initiate, modify or terminate functions of a space station
C	An amateur station located on the surface of the Earth for communication with other Earth stations by means of Earth satellites
D	An amateur station that receives telemetry from a satellite or balloon more than 50 kilometers above the surface of the Earth

6. - E1E05

What is the minimum passing score on all amateur operator license examinations?

Select	Answer
A	Minimum passing score of 77%
B	Minimum passing score of 80%
C	Minimum passing score of 70%
D	Minimum passing score of 74%

7. - E1F05

Amateur stations may not transmit in which of the following frequency segments if they are located in the contiguous 48 states and north of Line A?

Select	Answer
A	222 MHz - 223 MHz
B	53 MHz - 54 MHz
C	440 MHz - 450 MHz
D	420 MHz - 430 MHz

8. - E2A12

What is the purpose of digital store-and-forward functions on an amateur radio satellite?

Select	Answer
A	To relay messages between satellites
B	To upload operational software for the transponder
C	To delay download of telemetry between satellites
D	To store digital messages in the satellite for later download by other stations

9. - E2B04

How is color information sent in analog SSTV?

Select	Answer
A	Color information is sent on a 2.8 kHz subcarrier
B	Color is sent in a color burst at the end of each line
C	Color is amplitude modulated on the frequency modulated intensity signal
D	Color lines are sent sequentially

10. - E2C02

Which of the following best describes the term self-spotting? in connection with HF contest operating?

Select	Answer
A	An automatic method for rapidly zero beating or tuning to a station's frequency before calling that station
B	A manual technique for rapidly zero beating or tuning to a station's frequency before calling that station
C	The acceptable practice of manually posting the call signs of stations on a spotting network
D	The often-prohibited practice of posting one's own call sign and frequency on a spotting network

11. - E2D09

What type of modulation is used for JT65 contacts?

Select	Answer
A	PSK
B	Multi-tone AFSK
C	RTTY
D	IEEE 802.11

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?

Select	Answer
A	The protocol version you are using is not supported by the digital station
B	Another station you are unable to hear is using the frequency
C	All these choices are correct
D	Your transmit frequency is incorrect

13. - E3A09

Which of the following frequency ranges is most suited for meteor scatter communications?

Select	Answer
A	220 MHz - 450 MHz
B	28 MHz - 148 MHz
C	1.8 MHz - 1.9 MHz
D	10 MHz - 14 MHz

14. - E3B12

What is the primary characteristic of chordal hop propagation?

Select	Answer
A	Propagation away from the great circle bearing between stations
B	Signals reflected back toward the transmitting station
C	Propagation across the geomagnetic equator
D	Successive ionospheric refractions without an intermediate reflection from the ground

15. - E3C02

What is indicated by a rising A or K index?

Select	Answer
A	Decreasing disruption of the geomagnetic field
B	Higher levels of solar UV radiation
C	An increase in the critical frequency
D	Increasing disruption of the geomagnetic field

16. - E4A09

Which of the following is good practice when using an oscilloscope probe?

Select	Answer
A	Never use a DC-coupled probe to measure an AC circuit
B	Never use a high-impedance probe to measure a low-impedance circuit
C	Keep the signal ground connection of the probe as short as possible
D	All these choices are correct

17. - E4B02

What is the significance of voltmeter sensitivity expressed in ohms per volt?

Select	Answer
A	When used as a galvanometer, the reading in volts multiplied by the ohms per volt rating will determine the power drawn by the device under test
B	The full scale reading of the voltmeter multiplied by its ohms per volt rating will indicate the input impedance of the voltmeter
C	When used as an ohmmeter, the reading in ohms divided by the ohms per volt rating will determine the voltage applied to the circuit
D	When used as an ammeter, the full scale reading in amps divided by ohms per volt rating will determine the size of shunt needed

18. - E4C12

Which of the following has the largest effect on an SDR receiver's dynamic range?

Select	Answer
A	RAM speed used for data storage
B	Analog-to-digital converter sample width in bits
C	CPU register width in bits
D	Anti-aliasing input filter bandwidth

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?

Select	Answer
A	Neutralization
B	Amplifier desensitization
C	Adjacent channel interference
D	Intermodulation

20. - E4E02

Which of the following types of noise can often be reduced with a digital signal processing noise filter?

Select	Answer
A	Broadband white noise
B	Ignition noise
C	All these choices are correct
D	Power line noise

21. - E5A08

What is the phase relationship between the current through and the voltage across a series resonant circuit at resonance?

Select	Answer
A	The voltage leads the current by 90 degrees
B	The voltage and current are in phase
C	The current leads the voltage by 90 degrees
D	The voltage and current are 180 degrees out of phase

22. - E5B01

What is the term for the time required for the capacitor in an RC circuit to be charged to 63.2% of the applied voltage or to discharge to 36.8% of its initial voltage?

Select	Answer
A	A time factor of one
B	One exponential period
C	One time constant
D	An exponential rate of one

23. - E5C03

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

Select	Answer
A	A positive phase angle
B	A negative phase angle
C	A positive magnitude
D	A negative magnitude

24. - E5D04

Why are short connections used at microwave frequencies?

Select	Answer
A	To increase neutralizing resistance
B	To reduce phase shift along the connection
C	To reduce noise figure
D	To increase compensating capacitance

25. - E6A02

Which of the following semiconductor materials contains excess free electrons?

Select	Answer
A	Bipolar
B	P-type
C	N-type
D	Insulated gate

26. - E6B04

What type of semiconductor device is designed for use as a voltage-controlled capacitor?

Select	Answer
A	Varactor diode
B	Silicon-controlled rectifier
C	Zener diode
D	Tunnel diode

27. - E6C08

In Figure E6-3, what is the schematic symbol for a NAND gate?

Select	Answer
A	4
B	3
C	2
D	1

28. - E6D02

What is the equivalent circuit of a quartz crystal?

Select	Answer
A	Motional capacitance, motional inductance, loss resistance, and a capacitor representing electrode and stray capacitance all in parallel
B	Motional inductance and loss resistance in series, paralleled with motional capacitance and a capacitor representing electrode and stray capacitance
C	Motional capacitance, motional inductance, loss resistance, and a capacitor representing electrode and stray capacitance all in series
D	Motional capacitance, motional inductance, and loss resistance in series, all in parallel with a shunt capacitor representing electrode and stray capacitance

29. - E6E04

Which is the most common input and output impedance of circuits that use MMICs?

Select	Answer
A	50 ohms
B	300 ohms
C	450 ohms
D	10 ohms

30. - E6F03

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

Select	Answer
A	An LED and a phototransistor
B	A lens and a photomultiplier
C	A frequency modulated helium-neon laser
D	An amplitude modulated helium-neon laser

31. - E7A03

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

Select	Answer
A	A flip-flop
B	A multiplexer
C	An XOR gate
D	An OR gate

32. - E7B15

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

Select	Answer
A	Neutralization
B	Use a resistor in series with the emitter
C	All these choices are correct
D	Select transistors with high beta

33. - E7C09

What is a crystal lattice filter?

Select	Answer
A	A power supply filter made with interlaced quartz crystals
B	A filter using lattice-shaped quartz crystals for high-Q performance
C	A filter with narrow bandwidth and steep skirts made using quartz crystals
D	An audio filter made with four quartz crystals that resonate at 1 kHz intervals

34. - E7D15

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

Select	Answer
A	To compensate for variations of the incoming line voltage
B	To allow for remote control of the power supply
C	To allow the filter capacitors to charge gradually
D	To provide a dual-voltage output for reduced power applications

35. - E7E07

What is meant by the term "baseband" in radio communications?

Select	Answer
A	The frequency range occupied by a message signal prior to modulation
B	The basic oscillator frequency in an FM transmitter that is multiplied to increase the deviation and carrier frequency
C	The unmodulated bandwidth of the transmitted signal
D	The lowest frequency band that the transmitter or receiver covers

36. - E7F12

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

Select	Answer
A	All these choices are correct
B	FIR filters can respond faster to impulses
C	FIR filters can delay all frequency components of the signal by the same amount
D	FIR filters are easier to implement for a given set of passband rolloff requirements

37. - E7G05

How can unwanted ringing and audio instability be prevented in an op-amp RC audio filter circuit?

Select	Answer
A	Restrict Q but increase gain
B	Increase both gain and Q
C	Restrict gain but increase Q
D	Restrict both gain and Q

38. - E7H13

Which of the following is a technique for providing highly accurate and stable oscillators needed for microwave transmission and reception?

Select	Answer
A	All these choices are correct
B	Use a GPS signal reference
C	Use a rubidium stabilized reference oscillator
D	Use a temperature-controlled high Q dielectric resonator

39. - E8A03

What type of wave does a Fourier analysis show to be made up of sine waves of a given fundamental frequency plus all its harmonics?

Select	Answer
A	A sawtooth wave
B	A square wave
C	A cosine wave
D	A sine wave

40. - E8B02

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

Select	Answer
A	It increases as the RF carrier frequency increases
B	It does not depend on the RF carrier frequency
C	It decreases as the RF carrier frequency increases
D	It varies with the square root of the RF carrier frequency

41. - E8C01

How is Forward Error Correction implemented?

Select	Answer
A	By transmitting extra data that may be used to detect and correct transmission errors
B	By transmitting a special algorithm to the receiving station along with the data characters
C	By varying the frequency shift of the transmitted signal according to a predefined algorithm
D	By the receiving station repeating each block of three data characters

42. - E8D03

How does the spread spectrum technique of frequency hopping work?

Select	Answer
A	The frequency of the transmitted signal is changed very rapidly according to a pseudorandom sequence also used by the receiving station
B	If interference is detected by the receiver it will signal the transmitter to wait until the frequency is clear
C	If interference is detected by the receiver it will signal the transmitter to change frequencies
D	A 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?

Select	Answer
A	Antenna length divided by the number of elements
B	The angle formed between two imaginary lines drawn through the element ends
C	The frequency range over which an antenna satisfies a performance requirement
D	The angle between the half-power radiation points

44. - E9B02

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

Select	Answer
A	18 dB
B	14 dB
C	24 dB
D	36 dB

45. - E9C12

Which of the following describes an Extended Double Zepp antenna?

Select	Answer
A	A portable antenna erected using two push support poles
B	A center-fed 1.25-wavelength antenna (two 5/8-wave elements in phase)
C	A wideband vertical antenna constructed from precisely tapered aluminum tubing
D	An end-fed folded dipole antenna

46. - E9D06

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

Select	Answer
A	It is unchanged if the loading coil is located at a voltage maximum point
B	It is unchanged if the loading coil is located at the feed point
C	It is increased
D	It is decreased

47. - E9E05

How must an antenna's driven element be tuned to use a hairpin matching system?

Select	Answer
A	The driven element reactance must be capacitive
B	The driven element radiation resistance must be higher than the characteristic impedance of the transmission line
C	The driven element reactance must be inductive
D	The driven element resonance must be lower than the operating frequency

48. - E9F07

How does ladder line compare to small-diameter coaxial cable such as RG-58 at 50 MHz?

Select	Answer
A	Higher SWR
B	Lower loss
C	Lower velocity factor
D	Smaller reflection coefficient

49. - E9G07

On the Smith chart shown in Figure E9-3, what is the only straight line shown?

Select	Answer
A	The reactance axis
B	The resistance axis
C	The current axis
D	The voltage axis

50. - E9H10

How can the output voltage of a multiple-turn receiving loop antenna be increased?

Select	Answer
A	By increasing the number of turns and/or the area
B	By utilizing high impedance wire for the coupling loop
C	By winding adjacent turns in opposing directions
D	By reducing the permeability of the loop shield

Figure E6-3

Figure E9-1

Figure E9-3