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	Zinc oxide
B	Mica
C	Uranium Hexafluoride
D	Beryllium Oxide

2. - E1A06

Where must the carrier frequency of a CW signal be set to comply with FCC rules for 60 meter operation?

Select	Answer
A	On any frequency where the signal's sidebands are within the channel
B	At the center frequency of the channel
C	At the lowest frequency of the channel
D	At the highest frequency of the channel

3. - E1B04

What must be done before placing an amateur station within an officially designated wilderness area or wildlife preserve, or an area listed in the National Register of Historic Places?

Select	Answer
A	A proposal must be submitted to the National Park Service
B	A letter of intent must be filed with the Environmental Protection Agency
C	An Environmental Assessment must be submitted to the FCC
D	A form FSD-15 must be submitted to the Department of the Interior

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. - E1D02

Which of the following may transmit special codes intended to obscure the meaning of messages?

Select	Answer
A	Data containing personal information
B	Telecommand signals from a space telecommand station
C	Auxiliary relay links carrying repeater audio
D	Binary control characters

6. - E1E06

Who is responsible for the proper conduct and necessary supervision during an amateur operator license examination session?

Select	Answer
A	The FCC
B	The VE session manager
C	The VEC coordinating the session
D	Each administering VE

7. - E1F04

Which of the following geographic descriptions approximately describes "Line A"?

Select	Answer
A	A line roughly parallel to and north of the border between the U.S. and Mexico
B	A line roughly parallel to and south of the border between the U.S. and Canada
C	A line roughly parallel to and west of the U.S. Atlantic coastline
D	A line roughly parallel to and east of the U.S. Pacific coastline

8. - E2A05

What do the letters in a satellite's mode designator specify?

Select	Answer
A	The polarization of uplink and downlink signals
B	The uplink and downlink frequency ranges
C	Power limits for uplink and downlink transmissions
D	The location of the ground control station

9. - E2B10

What aspect of an analog slow-scan television signal encodes the brightness of the picture?

Select	Answer
A	Sync frequency
B	Tone frequency
C	Sync amplitude
D	Tone amplitude

10. - E2C05

What is the function of a DX QSL Manager?

Select	Answer
A	To run a net to allow many stations to contact a rare DX station
B	To relay calls to and from a DX station
C	To allocate frequencies for DXpeditions
D	To handle the receiving and sending of confirmation cards for a DX station

11. - E2D06

Which of the following describes a method of establishing EME contacts?

Select	Answer
A	High-speed CW identification to avoid fading
B	Storing and forwarding digital messages
C	Time synchronous transmissions alternately from each station
D	Judging optimum transmission times by monitoring beacons reflected from the moon

12. - E2E06

What is the most common data rate used for HF packet?

Select	Answer
A	110 baud
B	48 baud
C	1200 baud
D	300 baud

13. - E3A14

What is meant by circularly polarized electromagnetic waves?

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

14. - E3B11

At what time of day can sporadic E propagation occur?

Select	Answer
A	Any time
B	Only in hours of darkness
C	Only around sunset
D	Only around sunset and sunrise

15. - E3C09

How does the intensity of an X3 flare compare to that of an X2 flare?

Select	Answer
A	Four times as great
B	Twice as great
C	10 percent greater
D	50 percent greater

16. - E4A10

Which of the following displays multiple digital signal states simultaneously?

Select	Answer
A	Network analyzer
B	Bit error rate tester
C	Modulation monitor
D	Logic analyzer

17. - E4B11

Which of the following can be measured with a vector network analyzer?

Select	Answer
A	Reflection coefficient
B	All these choices are correct
C	Input impedance
D	Output impedance

18. - E4C10

What is an advantage of having a variety of receiver IF bandwidths from which to select?

Select	Answer
A	Multiple frequencies can be received simultaneously if desired
B	The noise figure of the RF amplifier can be adjusted to match the modulation type, thus increasing receiver sensitivity
C	Receive bandwidth can be set to match the modulation bandwidth, maximizing signal-to-noise ratio and minimizing interference
D	Receiver power consumption can be reduced when wider bandwidth is not required

19. - E4D01

What is meant by the blocking dynamic range of a receiver?

Select	Answer
A	The minimum difference in dB between the levels of two FM signals that will cause one signal to block the other
B	The minimum difference in dB between two signals which produce third-order intermodulation products greater than the noise floor
C	The difference in dB between the noise floor and the third-order intercept point
D	The difference in dB between the noise floor and the level of an incoming signal that will cause 1 dB of gain compression

20. - E4E03

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

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

21. - E5A03

What is the magnitude of the impedance of a series RLC circuit at resonance?

Select	Answer
A	Approximately equal to circuit resistance
B	High, as compared to the circuit resistance
C	Approximately equal to capacitive reactance
D	Approximately equal to inductive reactance

22. - E5B09

What is the relationship between the AC current through a capacitor and the voltage across a capacitor?

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

23. - E5C10

Which point on Figure E5-1 best represents the impedance of a series circuit consisting of a 400-ohm resistor and a 38-picofarad capacitor at 14 MHz?

Select	Answer
A	Point 6
B	Point 2
C	Point 5
D	Point 4

24. - E5D01

What is the result of skin effect?

Select	Answer
A	As frequency decreases, RF current flows in a thinner layer of the conductor, closer to the surface
B	Thermal effects on the surface of the conductor decrease the impedance
C	Thermal effects on the surface of the conductor increase the impedance
D	As frequency increases, RF current flows in a thinner layer of the conductor, closer to the surface

25. - E6A11

In Figure E6-1, what is the schematic symbol for a P-channel junction FET?

Select	Answer
A	6
B	2
C	1
D	3

26. - E6B11

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

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

27. - E6C03

What is tri-state logic?

Select	Answer
A	Proprietary logic devices manufactured by Tri-State Devices
B	Logic devices that utilize ternary math
C	Low-power logic devices designed to operate at 3 volts
D	Logic devices with 0, 1, and high-impedance output states

28. - E6D05

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

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

29. - E6E03

Which of the following materials is likely to provide the highest frequency of operation when used in MMICs?

Select	Answer
A	Silicon
B	Gallium nitride
C	Silicon dioxide
D	Silicon nitride

30. - E6F09

What is the efficiency of a photovoltaic cell?

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

31. - E7A02

What is the function of a decade counter?

Select	Answer
A	It produces one output pulse for every 10 input pulses
B	It decodes a decimal number for display on a seven-segment LED display
C	It produces 10 output pulses for every input pulse
D	It decodes a binary number for display on a seven-segment LED display

32. - E7B14

Why are switching amplifiers more efficient than linear amplifiers?

Select	Answer
A	Switching amplifiers use push-pull circuits
B	The power transistor is at saturation or cutoff most of the time
C	Linear amplifiers have high gain resulting in higher harmonic content
D	Switching amplifiers operate at higher voltages

33. - E7C10

Which of the following filters would be the best choice for use in a 2 meter band repeater duplexer?

Select	Answer
A	A cavity filter
B	An L-C filter
C	A crystal filter
D	A DSP filter

34. - E7D02

What is a characteristic of a switching electronic voltage regulator?

Select	Answer
A	The controlled device's duty cycle is changed to produce a constant average output voltage
B	It is generally less efficient than a linear regulator
C	It gives a ramp voltage at its output
D	The resistance of a control element is varied in direct proportion to the line voltage or load current

35. - E7E07

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

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

36. - E7F01

What is meant by direct digital conversion as applied to software defined radios?

Select	Answer
A	Incoming RF is converted to a control voltage for a voltage controlled oscillator
B	A switching mixer is used to generate I and Q signals directly from the RF input
C	Incoming RF is digitized by an analog-to-digital converter without being mixed with a local oscillator signal
D	Software is converted from source code to object code during operation of the receiver

37. - E7G11

What absolute voltage gain can be expected from the circuit in Figure E7-3 when R1 is 3300 ohms and RF is 47 kilohms?

Select	Answer
A	28
B	0.07
C	14
D	7

38. - E7H15

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

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

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

40. - E8B02

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

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

41. - E8C10

How may data rate be increased without increasing bandwidth?

Select	Answer
A	Increasing analog-to-digital conversion resolution
B	It is impossible
C	Using forward error correction
D	Using a more efficient digital code

42. - E8D06

What is the advantage of including parity bits in ASCII characters?

Select	Answer
A	Some types of errors can be detected
B	Foreign language characters can be sent
C	Faster transmission rate
D	The signal can overpower interfering signals

43. - E9A02

What is the effective radiated power relative to a dipole of a repeater station with 150 watts transmitter power output, 2 dB feed line loss, 2.2 dB duplexer loss, and 7 dBd antenna gain?

Select	Answer
A	1977 watts
B	78.7 watts
C	286 watts
D	420 watts

44. - E9B04

What is the front-to-back ratio of the radiation pattern shown in Figure E92?

Select	Answer
A	3 dB
B	28 dB
C	15 dB
D	38 dB

45. - E9C08

What is a folded dipole antenna?

Select	Answer
A	A dipole one-quarter wavelength long
B	A half-wave dipole with an additional parallel wire connecting its two ends
C	A dipole configured to provide forward gain
D	A type of ground-plane antenna

46. - E9D01

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

Select	Answer
A	3 dB
B	6 dB
C	2 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 allows single-band antennas to operate on other bands
B	It creates a low-angle radiation pattern
C	It prevents reflected power from traveling back down the feed line and causing harmonic radiation from the transmitter
D	It ensures that each driven element operates in concert with the others to create the desired antenna pattern

48. - E9F03

Why is the physical length of a coaxial cable transmission line shorter than its electrical length?

Select	Answer
A	Electrical signals move more slowly in a coaxial cable than in air
B	The surge impedance is higher in a parallel feed line
C	Skin effect is less pronounced in the coaxial cable
D	The characteristic impedance is higher in a parallel feed line

49. - E9G02

What type of coordinate system is used in a Smith chart?

Select	Answer
A	Voltage lines and current chords
B	Resistance circles and reactance arcs
C	Voltage circles and current arcs
D	Resistance lines and reactance chords

50. - E9H03

What is Receiving Directivity Factor (RDF)?

Select	Answer
A	Relative directivity compared to isotropic
B	Forward gain compared to average gain over the entire hemisphere
C	Relative directivity compared to a dipole
D	Forward gain compared to the gain in the reverse direction

Figure E5-1

Figure E6-1

Figure E7-3