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

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1. - E0A06

Why are there separate electric (E) and magnetic (H) field MPE limits?

Select	Answer
A	Ground reflections and scattering make the field strength vary with location
B	E field and H field radiation intensity peaks can occur at different locations
C	The body reacts to electromagnetic radiation from both the E and H fields
D	All these choices are correct

2. - E1A12

What special operating frequency restrictions are imposed on slow scan TV transmissions?

Select	Answer
A	They are restricted to phone band segments
B	None; they are allowed on all amateur frequencies
C	They are restricted to 7.245 MHz, 14.245 MHz, 21.345 MHz, and 28.945 MHz
D	They are not permitted above 54 MHz

3. - E1B03

Within what distance must an amateur station protect an FCC monitoring facility from harmful interference?

Select	Answer
A	3 miles
B	10 miles
C	30 miles
D	1 mile

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

5. - E1D04

Which of the following is required in the identification transmissions from a balloon-borne telemetry station?

Select	Answer
A	The output power of the balloon transmitter
B	All these choices are correct
C	Call sign
D	The station's six-character Maidenhead grid locator

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	Teaching an amateur operator license examination preparation course
B	Preparing, processing, administering, and coordinating an examination for an amateur radio operator license
C	Providing amateur operator license examination preparation training materials
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 50 MHz
B	Only on amateur frequencies above 222 MHz
C	Only on amateur frequencies above 420 MHz
D	Only on amateur frequencies above 144 MHz

8. - E2A03

How is the signal inverted by an inverting linear transponder?

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

9. - E2B06

What is vestigial sideband modulation?

Select	Answer
A	Amplitude modulation in which one complete sideband and a portion of the other are transmitted
B	Spread spectrum modulation achieved by applying FM modulation following single sideband amplitude modulation
C	A type of modulation in which one sideband is inverted
D	Narrow-band FM modulation achieved by filtering one sideband from the audio before frequency modulating the carrier

10. - E2C03

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

Select	Answer
A	33 centimeters
B	2 meters
C	6 meters
D	30 meters

11. - E2D08

What type of packet frame is used to transmit APRS beacon data?

Select	Answer
A	Unnumbered Information
B	Connect
C	Acknowledgement
D	Disconnect

12. - E2E02

What do the letters FEC mean as they relate to digital operation?

Select	Answer
A	First Error Correction
B	Forward Error Correction
C	Final Error Correction
D	Fatal Error Correction

13. - E3A12

What is the cause of auroral activity?

Select	Answer
A	The interaction in the E layer of charged particles from the Sun with the Earth's magnetic field
B	The interaction in the F2 layer between the solar wind and the Van Allen belt
C	Meteor showers concentrated in the extreme northern and southern latitudes
D	An extreme low-pressure area in the polar regions

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 equinoxes, especially the spring equinox
D	Around the solstices, especially the winter solstice

15. - E3C13

What type of polarization is best for ground-wave propagation?

Select	Answer
A	Circular
B	Elliptical
C	Vertical
D	Horizontal

16. - E4A01

Which of the following limits the highest frequency signal that can be accurately displayed on a digital oscilloscope?

Select	Answer
A	Amount of memory
B	Q of the circuit
C	Sampling rate of the analog-to-digital converter
D	All these choices are correct

17. - E4B07

What do the subscripts of S parameters represent?

Select	Answer
A	The relative time between measurements
B	The port or ports at which measurements are made
C	Frequency order of the measurements
D	Relative quality of the data

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?

Select	Answer
A	-164 dBm
B	-148 dBm
C	-155 dBm
D	-174 dBm

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	Amplifier desensitization
B	Intermodulation
C	Neutralization
D	Adjacent channel interference

20. - E4E03

Which of the following signals might a receiver noise blanker be able to remove from desired signals?

Select	Answer
A	Signals that appear across a wide bandwidth
B	Signals that appear at one IF but not another
C	Signals that have a sharply peaked frequency distribution
D	Signals that are constant at all IF levels

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

22. - E5B03

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

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

23. - E5C09

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

Select	Answer
A	The X axis represents the reactive component and the Y axis represents the resistive component
B	The X axis represents the resistive component and the Y axis represents the reactive component
C	The X axis represents the magnitude and the Y axis represents the phase angle
D	The X axis represents the phase angle and the Y axis represents the magnitude

24. - E5D13

How many watts are consumed in a circuit consisting of a 100-ohm resistor in series with a 100-ohm inductive reactance drawing 1 ampere?

Select	Answer
A	141.4 watts
B	200 watts
C	100 watts
D	70.7 watts

25. - E6A07

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

Select	Answer
A	Base-to-emitter resistance of approximately 0.6 to 0.7 ohms
B	Base-to-emitter resistance of approximately 6 to 7 ohms
C	Base-to-emitter voltage of approximately 6 to 7 volts
D	Base-to-emitter voltage of approximately 0.6 to 0.7 volts

26. - E6B11

What is used to control the attenuation of RF signals by a PIN diode?

Select	Answer
A	Capacitance of an RF coupling capacitor
B	A sub-harmonic pump signal
C	Forward DC bias current
D	Reverse voltage larger than the RF signal

27. - E6C07

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

Select	Answer
A	A resistor connected to an op-amp output that prevents signals from exceeding the power supply voltage
B	A resistor that ensures that an oscillator frequency does not drift
C	A resistor connected to the positive or negative supply line used to establish a voltage when an input or output is an open circuit
D	A resistor in a keying circuit used to reduce key clicks

28. - E6D05

What is one reason for using ferrite cores rather than powdered iron in an inductor?

Select	Answer
A	Ferrite toroids generally require fewer turns to produce a given inductance value
B	Ferrite toroids generally have better temperature stability
C	Ferrite toroids are easier to use with surface mount technology
D	Ferrite toroids generally have lower initial permeability

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. - E6F08

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

Select	Answer
A	Optoisolators provide impedance matching between the control circuit and power circuit
B	Optoisolators eliminate the effects of reflected light in the control circuit
C	Optoisolators provide a very high degree of electrical isolation between a control circuit and the circuit being switched
D	Optoisolators provide a low impedance link between a control circuit and a power circuit

31. - E7A05

Which of the following is a circuit that continuously alternates between two states without an external clock?

Select	Answer
A	T flip-flop
B	Astable multivibrator
C	J-K flip-flop
D	Monostable multivibrator

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	Select transistors with high beta
D	All these choices are correct

33. - E7C07

Which describes a Pi-L-network used for matching a vacuum tube final amplifier to a 50-ohm unbalanced output?

Select	Answer
A	A matching network in which all components are isolated from ground
B	A Pi-network with an additional series inductor on the output
C	A network with only three discrete parts
D	A Phase Inverter Load network

34. - E7D12

What is the dropout voltage of an analog voltage regulator?

Select	Answer
A	Minimum input-to-output voltage required to maintain regulation
B	Minimum input voltage for rated power dissipation
C	Maximum output voltage drops when the input voltage is varied over its specified range
D	Maximum that the output voltage may decrease at rated load

35. - E7E05

What circuit is added to an FM transmitter to boost the higher audio frequencies?

Select	Answer
A	A heterodyne enhancer
B	A pre-emphasis network
C	A heterodyne suppressor
D	A de-emphasis network

36. - E7F03

What type of digital signal processing filter is used to generate an SSB signal?

Select	Answer
A	A notch filter
B	An elliptical filter
C	A Hilbert-transform filter
D	An adaptive filter

37. - E7G03

What is the typical input impedance of an op-amp?

Select	Answer
A	Very high
B	1000 ohms
C	100 ohms
D	Very low

38. - E7H15

Which of these functions can be performed by a phase-locked loop?

Select	Answer
A	Photovoltaic conversion, optical coupling
B	Frequency synthesis, FM demodulation
C	Comparison of two digital input signals, digital pulse counter
D	Wide-band AF and RF power amplification

39. - E8A07

What determines the PEP-to-average power ratio of a single-sideband phone signal?

Select	Answer
A	Amplifier gain
B	Speech characteristics
C	The degree of carrier suppression
D	The frequency of the modulating signal

40. - E8B03

What is the modulation index of an FM-phone signal having a maximum frequency deviation of 3000 Hz either side of the carrier frequency when the modulating frequency is 1000 Hz?

Select	Answer
A	3
B	3000
C	1000
D	0.3

41. - E8C06

What is the bandwidth of a 170-hertz shift, 300-baud ASCII transmission?

Select	Answer
A	1.0 kHz
B	0.3 kHz
C	0.5 kHz
D	0.1 Hz

42. - E8D03

How does the spread spectrum technique of frequency hopping work?

Select	Answer
A	If interference is detected by the receiver it will signal the transmitter to wait until the frequency is clear
B	If interference is detected by the receiver it will signal the transmitter to change frequencies
C	A binary bit stream is used to shift the phase of an RF carrier very rapidly in a pseudorandom sequence
D	The frequency of the transmitted signal is changed very rapidly according to a pseudorandom sequence also used by the receiving station

43. - E9A05

What is included in the total resistance of an antenna system?

Select	Answer
A	Radiation resistance plus loss resistance
B	Radiation resistance plus transmission resistance
C	Radiation resistance plus space impedance
D	Transmission-line resistance plus radiation resistance

44. - E9B01

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

Select	Answer
A	75 degrees
B	30 degrees
C	50 degrees
D	25 degrees

45. - E9C12

Which of the following describes an Extended Double Zepp antenna?

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

46. - E9D07

What is an advantage of using top loading in a shortened HF vertical antenna?

Select	Answer
A	Improved radiation efficiency
B	Lower Q
C	Greater structural strength
D	Higher losses

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 gamma matching system
B	The omega matching system
C	The delta matching system
D	The stub matching system

48. - E9F06

What is the approximate physical length of an air-insulated, parallel conductor transmission line that is electrically 1/2 wavelength long at 14.10 MHz?

Select	Answer
A	13.3 meters
B	8.5 meters
C	7.0 meters
D	10.6 meters

49. - E9G11

How are the wavelength scales on a Smith chart calibrated?

Select	Answer
A	In fractions of antenna electrical wavelength
B	In fractions of antenna electrical frequency
C	In fractions of transmission line electrical wavelength
D	In fractions of transmission line electrical frequency

50. - E9H02

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

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

Figure E9-1