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

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1. - E0A09

Which insulating material commonly used as a thermal conductor for some types of electronic devices is extremely toxic if broken or crushed and the particles are accidentally inhaled?

Select	Answer
A	Beryllium Oxide
B	Uranium Hexafluoride
C	Mica
D	Zinc oxide

2. - E1A11

Which of the following describes authorization or licensing required when operating an amateur station aboard a U.S.-registered vessel in international waters?

Select	Answer
A	Only General Class or higher amateur licenses
B	Any FCC-issued amateur license
C	Any amateur license with an FCC Marine or Aircraft endorsement
D	An unrestricted Radiotelephone Operator Permit

3. - E1B07

To what type of regulations does PRB-1 apply?

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

4. - E1C07

At what level below a signal's mean power level is its bandwidth determined according to FCC rules?

Select	Answer
A	3 dB
B	26 dB
C	23 dB
D	6 dB

5. - E1D11

Which amateur stations are eligible to operate as Earth stations?

Select	Answer
A	Any amateur station whose licensee has filed a pre-space notification with the FCC's International Bureau
B	Any amateur station, subject to the privileges of the class of operator license held by the control operator
C	Only those of Amateur Extra Class operators
D	Only those of General, Advanced or Amateur Extra Class operators

6. - E1E05

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

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

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

10. - E2C09

What type of equipment is commonly used to implement an amateur radio mesh network?

Select	Answer
A	A wireless router running custom firmware
B	A 2 meter VHF transceiver with a 1200 baud modem
C	A 440 MHz transceiver with a 9600 baud modem
D	An optical cable connection between the USB ports of 2 separate computers

11. - E2D09

What type of modulation is used for JT65 contacts?

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

12. - E2E04

What is indicated when one of the ellipses in an FSK crossed-ellipse display suddenly disappears?

Select	Answer
A	Selective fading has occurred
B	The mark and space signal have been inverted
C	One of the signal filters is saturated
D	The receiver has drifted 5 kHz from the desired receive frequency

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	Meteor showers concentrated in the extreme northern and southern latitudes
C	The interaction in the F2 layer between the solar wind and the Van Allen belt
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 spring equinox
C	Around the equinoxes, especially the fall equinox
D	Around the solstices, especially the winter solstice

15. - E3C03

Which of the following signal paths is most likely to experience high levels of absorption when the A index or K index is elevated?

Select	Answer
A	Polar
B	Sporadic E
C	NVIS
D	Transequatorial

16. - E4A02

Which of the following parameters does a spectrum analyzer display on the vertical and horizontal axes?

Select	Answer
A	SWR and frequency
B	SWR and time
C	RF amplitude and time
D	RF amplitude and frequency

17. - E4B01

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

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

18. - E4C12

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

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

19. - E4D07

Which of the following reduces the likelihood of receiver desensitization?

Select	Answer
A	Switch from fast AGC to slow AGC
B	Decrease the RF bandwidth of the receiver
C	Increase the receiver front end gain
D	Raise the receiver IF frequency

20. - E4E09

What undesirable effect can occur when using an IF noise blanker?

Select	Answer
A	The audio frequency bandwidth of the received signal might be compressed
B	FM signals can no longer be demodulated
C	Nearby signals may appear to be excessively wide even if they meet emission standards
D	Received audio in the speech range might have an echo effect

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

22. - E5B10

What is the relationship between the AC current through an inductor and the voltage across an inductor?

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

23. - E5C01

Which of the following represents capacitive reactance in rectangular notation?

Select	Answer
A	-jX
B	+jX
C	Delta
D	Omega

24. - E5D07

How many watts are consumed in a circuit having a power factor of 0.71 if the apparent power is 500VA?

Select	Answer
A	355 W
B	252 W
C	704 W
D	1.42 mW

25. - E6A01

In what application is gallium arsenide used as a semiconductor material?

Select	Answer
A	In very low-frequency RF circuits
B	In high-current rectifier circuits
C	In microwave circuits
D	In high-power audio circuits

26. - E6B03

What type of bias is required for an LED to emit light?

Select	Answer
A	Zero bias
B	Forward bias
C	Inductive bias
D	Reverse bias

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. - E6D08

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

Select	Answer
A	Powdered-iron cores generally maintain their characteristics at higher currents
B	Powdered-iron cores generally have greater initial permeability
C	Powdered-iron cores use smaller diameter wire for the same inductance
D	Powdered-iron cores generally require fewer turns to produce a given inductance

29. - E6E01

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

Select	Answer
A	Higher noise figures
B	Lower junction voltage drop
C	Higher electron mobility
D	Lower transconductance

30. - E6F06

Which of these materials is most commonly used to create photoconductive devices?

Select	Answer
A	A heavy metal
B	A liquid semiconductor
C	An ordinary metal
D	A crystalline semiconductor

31. - E7A11

What type of logic defines "1" as a high voltage?

Select	Answer
A	Reverse Logic
B	Assertive Logic
C	Negative logic
D	Positive Logic

32. - E7B10

In Figure E7-1, what is the purpose of R1 and R2?

Select	Answer
A	Voltage divider bias
B	Feedback
C	Self bias
D	Load resistors

33. - E7C09

What is a crystal lattice filter?

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

34. - E7D06

What is the purpose of Q1 in the circuit shown in Figure E7-2?

Select	Answer
A	It controls the current supplied to the load
B	It provides negative feedback to improve regulation
C	It provides a constant load for the voltage source
D	It provides D1 with current

35. - E7E03

What is a frequency discriminator stage in a FM receiver?

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

36. - E7F05

How frequently must an analog signal be sampled by an analog-to-digital converter so that the signal can be accurately reproduced?

Select	Answer
A	At least half the rate of the highest frequency component of the signal
B	At the same rate as the highest frequency component of the signal
C	At least twice the rate of the highest frequency component of the signal
D	At four times the rate of the highest frequency component of the signal

37. - E7G12

What is an operational amplifier?

Select	Answer
A	A high-gain, direct-coupled differential amplifier with very high input impedance and very low output impedance
B	A RF amplifier used in the UHF and microwave regions
C	A digital audio amplifier whose characteristics are determined by components external to the amplifier
D	An amplifier used to increase the average output of frequency modulated amateur signals to the legal limit

38. - E7H15

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

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

39. - E8A11

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

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

40. - E8B07

Orthogonal Frequency Division Multiplexing is a technique used for which type of amateur communication?

Select	Answer
A	High-speed digital modes
B	OFDM signals are not allowed on amateur bands
C	Extremely low-power contacts
D	EME

41. - E8C07

What is the bandwidth of a 4800-Hz frequency shift, 9600-baud ASCII FM transmission?

Select	Answer
A	5.76 kHz
B	4.8 kHz
C	9.6 kHz
D	15.36 kHz

42. - E8D02

What spread spectrum communications technique uses a high-speed binary bit stream to shift the phase of an RF carrier?

Select	Answer
A	Frequency hopping
B	Phase compandored spread spectrum
C	Direct sequence
D	Binary phase-shift keying

43. - E9A11

Which of the following factors determines ground losses for a ground-mounted vertical antenna operating in the 3 MHz to 30 MHz range?

Select	Answer
A	The standing wave ratio
B	Soil conductivity
C	Distance from the transmitter
D	Take-off angle

44. - E9B05

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

Select	Answer
A	Azimuth
B	Polarization
C	Radiation resistance
D	Elevation

45. - E9C10

Which of the following describes a Zepp antenna?

Select	Answer
A	An end-fed dipole antenna
B	A dipole constructed from zip cord
C	An omni-directional antenna commonly used for satellite communications
D	A vertical array capable of quickly changing the direction of maximum radiation by changing phasing lines

46. - E9D01

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

Select	Answer
A	2 dB
B	3 dB
C	6 dB
D	4 dB

47. - E9E11

What is the primary purpose of phasing lines when used with an antenna having multiple driven elements?

Select	Answer
A	It prevents reflected power from traveling back down the feed line and causing harmonic radiation from the transmitter
B	It allows single-band antennas to operate on other bands
C	It creates a low-angle radiation pattern
D	It ensures that each driven element operates in concert with the others to create the desired antenna pattern

48. - E9F13

What impedance does a 1/4-wavelength transmission line present to a generator when the line is shorted at the far end?

Select	Answer
A	Very low impedance
B	Very high impedance
C	The same as the characteristic impedance of the transmission line
D	The same as the generator output impedance

49. - E9G09

What third family of circles is often added to a Smith chart during the process of solving problems?

Select	Answer
A	Standing wave ratio circles
B	Coaxial-length circles
C	Radiation-pattern circles
D	Antenna-length circles

50. - E9H04

What is an advantage of placing a grounded electrostatic shield around a small loop direction-finding antenna?

Select	Answer
A	It eliminates unbalanced capacitive coupling to the surroundings, improving the nulls
B	It increases signal strength by providing a better match to the feed line
C	It adds capacitive loading, increasing the bandwidth of the antenna
D	It eliminates tracking errors caused by strong out-of-band signals

Figure E6-3

Figure E7-1

Figure E7-2

Figure E9-2