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

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1. - E0A04

When evaluating a site with multiple transmitters operating at the same time, the operators and licensees of which transmitters are responsible for mitigating over-exposure situations?

Select	Answer
A	Only commercial transmitters
B	Only the most powerful transmitter
C	Each transmitter operating with a duty cycle greater than 50 percent
D	Each transmitter that produces 5 percent or more of its MPE limit in areas where the total MPE limit is exceeded.

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?

Select	Answer
A	14.070 MHz
B	14.149 MHz
C	14.100 MHz
D	14.349 MHz

3. - E1B07

To what type of regulations does PRB-1 apply?

Select	Answer
A	Use of wireless devices in vehicles
B	FAA tower height limits
C	State and local zoning
D	Homeowners associations

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.?

Select	Answer
A	CEPT agreement
B	ITU reciprocal license
C	All these choices are correct
D	IARP agreement

5. - E1D01

What is the definition of telemetry?

Select	Answer
A	One-way transmission of measurements at a distance from the measuring instrument
B	One-way transmission that initiates, modifies, or terminates the functions of a device at a distance
C	Two-way transmissions of data
D	Two-way transmissions in excess of 1000 feet

6. - E1E07

What should a VE do if a candidate fails to comply with the examiner's instructions during an amateur operator license examination?

Select	Answer
A	Immediately terminate everyone's examination and close the session
B	Immediately terminate the candidate's examination
C	Allow the candidate to complete the examination, but invalidate the results
D	Warn the candidate that continued failure to comply will result in termination of the examination

7. - E1F07

When may an amateur station send a message to a business?

Select	Answer
A	When the control operator is employed by the FCC or another government agency
B	When the total money involved does not exceed $25
C	When transmitting international third-party communications
D	When neither the amateur nor his or her employer has a pecuniary interest in the communications

8. - E2A03

How is the signal inverted by an inverting linear transponder?

Select	Answer
A	The signal is detected and remodulated on the reverse sideband
B	The signal is passed through a mixer and the difference rather than the sum is transmitted
C	The signal is passed through a non-linear filter
D	The signal is reduced to I and Q components and the Q component is filtered out

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 amplitude modulated on the frequency modulated intensity signal
C	Color is sent in a color burst at the end of each line
D	Color lines are sent sequentially

10. - E2C08

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

Select	Answer
A	Repeater contacts between U.S. club members
B	Contacts between a U.S. station and a non-U.S. station
C	Contacts using tactical call signs
D	Special event contacts between stations in the U.S.

11. - E2D11

Which of the following data are used by the APRS network to communicate station location?

Select	Answer
A	Latitude and longitude
B	Radio direction finding spectrum analysis
C	Time and frequency
D	Polar coordinates

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

13. - E3A01

What is the approximate maximum separation measured along the surface of the Earth between two stations communicating by EME?

Select	Answer
A	2000 miles, if the moon is at apogee
B	12,000 miles, if the moon is visible by both stations
C	5000 miles, if the moon is at perigee
D	500 miles, if the moon is at perigee

14. - E3B03

What is the best time of day for transequatorial propagation?

Select	Answer
A	Afternoon or early evening
B	Late at night
C	Noon
D	Morning

15. - E3C14

Why does the radio-path horizon distance exceed the geometric horizon?

Select	Answer
A	Downward bending due to density variations in the atmosphere
B	E-region skip
C	Due to the Doppler effect
D	D-region skip

16. - E4A07

Which of the following is an advantage of using an antenna analyzer compared to an SWR bridge to measure antenna SWR?

Select	Answer
A	All these choices are correct
B	Antenna analyzers display a time-varying representation of the modulation envelope
C	Antenna analyzers do not need an external RF source
D	Antenna analyzers automatically tune your antenna for resonance

17. - E4B01

Which of the following factors most affects the accuracy of a frequency counter?

Select	Answer
A	Time base accuracy
B	Input attenuator accuracy
C	Temperature coefficient of the logic
D	Decade divider accuracy

18. - E4C08

An SDR receiver is overloaded when input signals exceed what level?

Select	Answer
A	One-half the maximum sampling buffer size
B	The maximum count value of the analog-to-digital converter
C	One-half the maximum sample rate
D	The reference voltage of the analog-to-digital converter

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?

Select	Answer
A	173.35 MHz and 139.40 MHz
B	146.34 MHz and 146.61 MHz
C	146.10 MHz and 147.30 MHz
D	146.88 MHz and 146.34 MHz

20. - E4E07

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

Select	Answer
A	Common-mode currents on the shield and conductors
B	Use of braided shielding material
C	Tying all ground connections to a common point resulting in differential-mode currents in the shield
D	Low inductance ground connections at both ends of the shield

21. - E5A12

What is the half-power bandwidth of a resonant circuit that has a resonant frequency of 3.7 MHz and a Q of 118?

Select	Answer
A	31.4 kHz
B	218.3 kHz
C	15.7 kHz
D	436.6 kHz

22. - E5B06

What is susceptance?

Select	Answer
A	The imaginary part of admittance
B	A measure of the efficiency of a transformer
C	The ratio of magnetic field to electric field
D	The magnetic impedance of a circuit

23. - E5C07

Where is the impedance of a pure resistance plotted on rectangular coordinates?

Select	Answer
A	On the horizontal axis
B	On the vertical axis
C	On a horizontal line, offset vertically above the horizontal axis
D	On a line through the origin, slanted at 45 degrees

24. - E5D10

How can the true power be determined in an AC circuit where the voltage and current are out of phase?

Select	Answer
A	By multiplying the apparent power by the power factor
B	By dividing the reactive power by the power factor
C	By multiplying the reactive power by the power factor
D	By dividing the apparent power by the power factor

25. - E6A05

How does DC input impedance at the gate of a field-effect transistor compare with the DC input impedance of a bipolar transistor?

Select	Answer
A	They are both high impedance
B	They are both low impedance
C	An FET has lower input impedance
D	An FET has higher input impedance

26. - E6B06

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

Select	Answer
A	As a variable capacitance in an automatic frequency control circuit
B	As a rectifier in high current power supplies
C	As a constant voltage reference in a power supply
D	As a VHF/UHF mixer or detector

27. - E6C10

In Figure E6-3, what is the schematic symbol for a NOR gate?

Select	Answer
A	4
B	1
C	2
D	3

28. - E6D03

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

Select	Answer
A	Increased conductivity in the presence of light
B	Mechanical deformation of material by the application of a magnetic field
C	Mechanical deformation of material by the application of a voltage
D	Generation of electrical energy in the presence of light

29. - E6E09

Which of the following component package types would be most suitable for use at frequencies above the HF range?

Select	Answer
A	Surface mount
B	TO-220
C	Radial lead
D	Axial lead

30. - E6F09

What is the efficiency of a photovoltaic cell?

Select	Answer
A	Cost per kilowatt-hour generated
B	The open-circuit voltage divided by the short-circuit current under full illumination
C	The relative fraction of light that is converted to current
D	The output RF power divided by the input DC power

31. - E7A08

What logical operation does an OR gate perform?

Select	Answer
A	It produces logic 1 at its output if any or all inputs are logic 1
B	It produces logic 1 at its output if all inputs are logic 0
C	It produces logic 0 at its output if all inputs are logic 1
D	It only produces logic 0 at its output when all inputs are logic 1

32. - E7B13

Which of the following describes an emitter follower (or common collector) amplifier?

Select	Answer
A	An amplifier with a low impedance output that follows the base input voltage
B	An OR circuit with only one emitter used for output
C	A differential amplifier with both inputs fed to the emitter of the input transistor
D	A two-transistor amplifier with the emitters sharing a common bias resistor

33. - E7C04

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

Select	Answer
A	It introduces negative resistance to cancel the resistive part of impedance
B	Reactive currents are dissipated in matched resistances
C	It cancels the reactive part of the impedance and changes the resistive part to a desired value
D	It introduces transconductance to cancel the reactive part of impedance

34. - E7D09

What is the main reason to use a charge controller with a solar power system?

Select	Answer
A	Prevention of battery damage due to overcharge
B	Matching of day and night charge rates
C	Prevention of battery undercharge
D	Control of electrolyte levels during battery discharge

35. - E7E02

What is the function of a reactance modulator?

Select	Answer
A	To produce AM signals by using an electrically variable inductance or capacitance
B	To produce PM or FM signals by using an electrically variable inductance or capacitance
C	To produce AM signals by using an electrically variable resistance
D	To produce PM signals by using an electrically variable resistance

36. - E7F08

What is the function of decimation?

Select	Answer
A	Converting data to binary code decimal form
B	Removing unnecessary significant digits
C	Attenuating the signal
D	Reducing the effective sample rate by removing samples

37. - E7G04

What is meant by the "op-amp input offset voltage"?

Select	Answer
A	The potential between the amplifier input terminals of the op-amp in an open loop condition
B	The difference between the output voltage of the op-amp and the input voltage required in the immediately following stage
C	The output voltage of the op-amp minus its input voltage
D	The differential input voltage needed to bring the open loop output voltage to zero

38. - E7H12

Which of the following must be done to ensure that a crystal oscillator provides the frequency specified by the crystal manufacturer?

Select	Answer
A	Bias the crystal at a specified voltage
B	Bias the crystal at a specified current
C	Provide the crystal with a specified parallel inductance
D	Provide the crystal with a specified parallel capacitance

39. - E8A11

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

Select	Answer
A	Total harmonic distortion
B	Peak envelope power
C	Power factor
D	Reciprocal mixing

40. - E8B05

What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus-or-minus 5 kHz when the maximum modulation frequency is 3 kHz?

Select	Answer
A	1.67
B	60
C	0.6
D	0.167

41. - E8C05

What is the approximate bandwidth of a 13-WPM International Morse Code transmission?

Select	Answer
A	26 Hz
B	52 Hz
C	13 Hz
D	104 Hz

42. - E8D10

What are some of the differences between the Baudot digital code and ASCII?

Select	Answer
A	Baudot uses 6 data bits per character, ASCII uses 7 or 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes
B	Baudot uses 7 data bits per character, ASCII uses 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes
C	Baudot uses 5 data bits per character, ASCII uses 7 or 8; Baudot uses 2 characters as letters/figures shift codes, ASCII has no letters/figures shift code
D	Baudot uses 4 data bits per character, ASCII uses 7 or 8; Baudot uses 1 character as a letters/figures shift code, ASCII has no letters/figures code

43. - E9A12

How much gain does an antenna have compared to a 1/2-wavelength dipole when it has 6 dB gain over an isotropic antenna?

Select	Answer
A	3.85 dB
B	2.79 dB
C	8.15 dB
D	6.0 dB

44. - E9B10

What is the principle of a Method of Moments analysis?

Select	Answer
A	A wire is modeled as a series of segments, each having a uniform value of current
B	A wire is modeled as a series of segments, each having a distinct value of voltage across it
C	A wire is modeled as a single sine-wave voltage source
D	A wire is modeled as a single sine-wave current generator

45. - E9C13

How does the radiation pattern of a horizontally polarized 3-element beam antenna vary with increasing height above ground?

Select	Answer
A	The horizontal beamwidth increases
B	The takeoff angle of the lowest elevation lobe decreases
C	The horizontal beamwidth decreases
D	The takeoff angle of the lowest elevation lobe increases

46. - E9D03

Where should a high Q loading coil be placed to minimize losses in a shortened vertical antenna?

Select	Answer
A	At a voltage node
B	As low as possible on the vertical radiator
C	Near the center of the vertical radiator
D	As close to the transmitter as possible

47. - E9E06

Which of these feed line impedances would be suitable for constructing a quarter-wave Q-section for matching a 100-ohm loop to 50-ohm feed line?

Select	Answer
A	450 ohms
B	62 ohms
C	75 ohms
D	50 ohms

48. - E9F01

What is the velocity factor of a transmission line?

Select	Answer
A	The index of shielding for coaxial cable
B	The ratio of the characteristic impedance of the line to the terminating impedance
C	The velocity of the wave in the transmission line divided by the velocity of light in a vacuum
D	The velocity of the wave in the transmission line multiplied by the velocity of light in a vacuum

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 current axis
C	The voltage axis
D	The resistance axis

50. - E9H02

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

Select	Answer
A	All these choices are correct
B	They must be erected at least 1/2 wavelength above the ground to attain good directivity
C	Atmospheric noise is so high that gain over a dipole is not important
D	Low loss coax transmission line is essential for good performance

Figure E6-3

Figure E9-3