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?

Select	Answer
A	Ingestion of ozone gas from the cooling system
B	Blood clotting from the intense magnetic field
C	Hearing loss caused by high voltage corona discharge
D	Localized heating of the body from RF exposure in excess of the MPE limits

2. - E1A07

What is the maximum power permitted on the 2200 meter band?

Select	Answer
A	50 watts PEP
B	5 watts EIRP (Equivalent isotropic radiated power)
C	1 watt EIRP (Equivalent isotropic radiated power)
D	100 watts PEP

3. - E1B11

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

Select	Answer
A	Amateur radio operations must be permitted in any private residence
B	Reasonable accommodations of amateur radio must be made
C	Use of wireless devices in a vehicle is exempt from regulation
D	No limitations may be placed on antenna size or placement

4. - E1C04

What is meant by IARP?

Select	Answer
A	The internal amateur radio practices policy of the FCC
B	An international amateur radio permit that allows U.S. amateurs to operate in certain countries of the Americas
C	An indication of increased antenna reflected power
D	A forecast of intermittent aurora radio propagation

5. - E1D06

What is the maximum permitted transmitter output power when operating a model craft by telecommand?

Select	Answer
A	100 watts
B	5 watts
C	1 watt
D	2 watts

6. - E1E01

For which types of out-of-pocket expenses do the Part 97 rules state that VEs and VECs may be reimbursed?

Select	Answer
A	Preparing, processing, administering, and coordinating an examination for an amateur radio operator license
B	Providing amateur operator license examination preparation training materials
C	Teaching an amateur operator license examination preparation course
D	No expenses are authorized for reimbursement

7. - E1F01

On what frequencies are spread spectrum transmissions permitted?

Select	Answer
A	Only on amateur frequencies above 420 MHz
B	Only on amateur frequencies above 144 MHz
C	Only on amateur frequencies above 222 MHz
D	Only on amateur frequencies above 50 MHz

8. - E2A07

Which of the following types of signals can be relayed through a linear transponder?

Select	Answer
A	All these choices are correct
B	FM and CW
C	SSB and SSTV
D	PSK and packet

9. - E2B11

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

Select	Answer
A	To identify the SSTV mode being used
B	To provide vertical synchronization
C	To lock the color burst oscillator in color SSTV images
D	To identify the call sign of the station transmitting

10. - E2C12

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

Select	Answer
A	Custom code plugs for the local trunking systems
B	Forward error correction and Viterbi codes
C	Discovery and link establishment protocols
D	Acting as store-and-forward digipeaters

11. - E2D05

What is one advantage of the JT65 mode?

Select	Answer
A	Permits fast-scan TV transmissions over narrow bandwidth
B	Uses only a 65 Hz bandwidth
C	The ability to decode signals which have a very low signal-to-noise ratio
D	Easily copied by ear if necessary

12. - E2E09

Which of the following HF digital modes uses variable-length coding for bandwidth efficiency?

Select	Answer
A	PACTOR
B	RTTY
C	PSK31
D	MT63

13. - E3A14

What is meant by circularly polarized electromagnetic waves?

Select	Answer
A	Waves produced by a loop antenna
B	Waves that circle the Earth
C	Waves with an electric field bent into a circular shape
D	Waves with a rotating electric field

14. - E3B09

At what time of year is sporadic E propagation most likely to occur?

Select	Answer
A	Around the solstices, especially the summer solstice
B	Around the equinoxes, especially the fall equinox
C	Around the solstices, especially the winter solstice
D	Around the equinoxes, especially the spring equinox

15. - E3C12

How does the maximum range of ground-wave propagation change when the signal frequency is increased?

Select	Answer
A	It decreases
B	It stays the same
C	It increases
D	It peaks at roughly 14 MHz

16. - E4A06

What is the effect of aliasing on a digital oscilloscope caused by setting the time base too slow?

Select	Answer
A	Excessive blanking occurs, which prevents display of the signal
B	Calibration of the vertical scale is no longer valid
C	All signals will have a DC offset
D	A false, jittery low-frequency version of the signal is displayed

17. - E4B03

Which S parameter is equivalent to forward gain?

Select	Answer
A	S12
B	S11
C	S21
D	S22

18. - E4C11

Why can an attenuator be used to reduce receiver overload on the lower frequency HF bands with little or no impact on signal-to-noise ratio?

Select	Answer
A	Signals are attenuated separately from the noise
B	The attenuator has a noise filter to suppress interference
C	Atmospheric noise is generally greater than internally generated noise even after attenuation
D	The attenuator has a low-pass filter to increase the strength of lower frequency signals

19. - E4D12

What is the term for the reduction in receiver sensitivity caused by a strong signal near the received frequency?

Select	Answer
A	Cross-modulation interference
B	Squelch gain rollback
C	Desensitization
D	Quieting

20. - E4E10

What might be the cause of a loud roaring or buzzing AC line interference that comes and goes at intervals?

Select	Answer
A	A malfunctioning illuminated advertising display
B	All these choices are correct
C	A defective doorbell or doorbell transformer inside a nearby residence
D	Arcing contacts in a thermostatically controlled device

21. - E5A06

What is the magnitude of the circulating current within the components of a parallel LC circuit at resonance?

Select	Answer
A	It is at a maximum
B	It is at a minimum
C	It equals 2 multiplied by pi, multiplied by frequency, multiplied by inductance
D	It equals 1 divided by the quantity 2 times pi, multiplied by the square root of inductance L multiplied by capacitance C

22. - E5B03

How is impedance in polar form converted to an equivalent admittance?

Select	Answer
A	Take the square root of the magnitude and add 180 degrees to the angle
B	Take the reciprocal of the angle and change the sign of the magnitude
C	Square the magnitude and subtract 90 degrees from the angle
D	Take the reciprocal of the magnitude and change the sign of the angle

23. - E5C08

What coordinate system is often used to display the phase angle of a circuit containing resistance, inductive and/or capacitive reactance?

Select	Answer
A	Faraday grid
B	Maidenhead grid
C	Elliptical coordinates
D	Polar coordinates

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

25. - E6A10

In Figure E6-1, what is the schematic symbol for an N-channel dual-gate MOSFET?

Select	Answer
A	6
B	5
C	4
D	2

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. - E6C01

What is the function of hysteresis in a comparator?

Select	Answer
A	To increase the sensitivity
B	To cause the output to change states continually
C	To allow the comparator to be used with AC input signals
D	To prevent input noise from causing unstable output signals

28. - E6D09

What devices are commonly used as VHF and UHF parasitic suppressors at the input and output terminals of a transistor HF amplifier?

Select	Answer
A	Butterworth filters
B	Electrolytic capacitors
C	Steel-core toroids
D	Ferrite beads

29. - E6E02

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

Select	Answer
A	PLCC
B	DIP
C	Ball grid array
D	SOT

30. - E6F04

What is the photovoltaic effect?

Select	Answer
A	The tendency of a battery to discharge when exposed to light
B	The conversion of light to electrical energy
C	The conversion of electrical energy to mechanical energy
D	The conversion of voltage to current when exposed to light

31. - E7A06

What is a characteristic of a monostable multivibrator?

Select	Answer
A	It maintains a constant output voltage, regardless of variations in the input voltage
B	It produces a continuous square wave oscillating between 1 and 0
C	It switches momentarily to the opposite binary state and then returns to its original state after a set time
D	It stores one bit of data in either a 0 or 1 state

32. - E7B16

What is the effect of intermodulation products in a linear power amplifier?

Select	Answer
A	All these choices are correct
B	Creation of parasitic oscillations
C	Low efficiency
D	Transmission of spurious signals

33. - E7C09

What is a crystal lattice filter?

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

34. - E7D03

What device is typically used as a stable voltage reference in a linear voltage regulator?

Select	Answer
A	An SCR
B	A Zener diode
C	A tunnel diode
D	A varactor diode

35. - E7E03

What is a frequency discriminator stage in a FM receiver?

Select	Answer
A	A circuit for detecting FM signals
B	A circuit for filtering two closely adjacent signals
C	An automatic band-switching circuit
D	An FM generator circuit

36. - E7F09

Why is an anti-aliasing digital filter required in a digital decimator?

Select	Answer
A	It notches out the sampling frequency to avoid sampling errors
B	It removes high-frequency signal components that would otherwise be reproduced as lower frequency components
C	It peaks the response of the decimator, improving bandwidth
D	It removes low-frequency signal components to eliminate the need for DC restoration

37. - E7G05

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

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

38. - E7H14

What is a phase-locked loop circuit?

Select	Answer
A	An electronic servo loop consisting of a ratio detector, reactance modulator, and voltage-controlled oscillator
B	An electronic circuit also known as a monostable multivibrator
C	An electronic servo loop consisting of a phase detector, a low-pass filter, a voltage-controlled oscillator, and a stable reference oscillator
D	An electronic circuit consisting of a precision push-pull amplifier with a differential input

39. - E8A02

Which of the following is a type of analog-to-digital conversion?

Select	Answer
A	Phase reversal
B	Harmonic regeneration
C	Level shifting
D	Successive approximation

40. - E8B08

What describes Orthogonal Frequency Division Multiplexing?

Select	Answer
A	A bandwidth compression technique using Fourier transforms
B	A digital mode for narrow-band, slow-speed transmissions
C	A frequency modulation technique that uses non-harmonically related frequencies
D	A digital modulation technique using subcarriers at frequencies chosen to avoid intersymbol interference

41. - E8C05

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

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

42. - E8D07

What is a common cause of overmodulation of AFSK signals?

Select	Answer
A	Bit errors in the modem
B	Excessive transmit audio levels
C	Excessive numbers of retries
D	Ground loops

43. - E9A01

What is an isotropic antenna?

Select	Answer
A	A theoretical, omnidirectional antenna used as a reference for antenna gain
B	A spacecraft antenna used to direct signals toward Earth
C	A grounded antenna used to measure Earth conductivity
D	A horizontally polarized antenna used to compare Yagi antennas

44. - E9B05

What type of antenna pattern is shown in Figure E9-2?

Select	Answer
A	Elevation
B	Polarization
C	Radiation resistance
D	Azimuth

45. - E9C06

What is the effect of adding a terminating resistor to a rhombic antenna?

Select	Answer
A	It changes the radiation pattern from horizontal to vertical polarization
B	It decreases the ground loss
C	It reflects the standing waves on the antenna elements back to the transmitter
D	It changes the radiation pattern from bidirectional to unidirectional

46. - E9D09

What is the function of a loading coil used as part of an HF mobile antenna?

Select	Answer
A	To lower the losses
B	To cancel capacitive reactance
C	To increase the SWR bandwidth
D	To lower the Q

47. - E9E01

What system matches a higher-impedance transmission line to a lower-impedance antenna by connecting the line to the driven element in two places spaced a fraction of a wavelength each side of element center?

Select	Answer
A	The delta matching system
B	The omega matching system
C	The gamma matching system
D	The stub matching system

48. - E9F09

What is the approximate physical length of a foam polyethylene dielectric coaxial transmission line that is electrically 1/4 wavelength long at 7.2 MHz?

Select	Answer
A	8.3 meters
B	10.4 meters
C	6.9 meters
D	5.2 meters

49. - E9G04

What are the two families of circles and arcs that make up a Smith chart?

Select	Answer
A	Resistance and reactance
B	Reactance and voltage
C	Resistance and voltage
D	Voltage and impedance

50. - E9H06

What is the triangulation method of direction finding?

Select	Answer
A	A fixed receiving station plots three headings to the signal source
B	The geometric angles of sky waves from the source are used to determine its position
C	Antenna headings from several different receiving locations are used to locate the signal source
D	A fixed receiving station uses three different antennas to plot the location of the signal source

Figure E6-1

Figure E9-2