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	Uranium Hexafluoride
B	Beryllium Oxide
C	Zinc oxide
D	Mica

2. - E1A04

With your transceiver displaying the carrier frequency of phone signals, you hear a DX station calling CQ on 3.601 MHz LSB. Is it legal to return the call using lower sideband on the same frequency?

Select	Answer
A	No, U.S. stations are not permitted to use phone emissions below 3.610 MHz
B	Yes, because the DX station initiated the contact
C	No, the sideband will extend beyond the edge of the phone band segment
D	Yes, because the displayed frequency is within the 75 meter phone band segment

3. - E1B05

What is the National Radio Quiet Zone?

Select	Answer
A	An area surrounding the National Radio Astronomy Observatory
B	An area in Florida surrounding Cape Canaveral
C	An area in Puerto Rico surrounding the Arecibo Radio Telescope
D	An area in New Mexico surrounding the White Sands Test Area

4. - E1C08

What is the maximum permissible duration of a remotely controlled station's transmissions if its control link malfunctions?

Select	Answer
A	3 minutes
B	10 minutes
C	5 minutes
D	30 seconds

5. - E1D07

Which HF amateur bands have frequencies authorized for space stations?

Select	Answer
A	All HF bands
B	Only the 40, 20, 17, 15, and 10 meter bands
C	Only the 40, 30, 20, 15, 12, and 10 meter bands
D	Only the 40, 20, 17, 15, 12, and 10 meter bands

6. - E1E02

Who does Part 97 task with maintaining the pools of questions for all U.S. amateur license examinations?

Select	Answer
A	The FCC
B	The VECs
C	The VEs
D	The ARRL

7. - E1F09

Which of the following conditions apply when transmitting spread spectrum emissions?

Select	Answer
A	All these choices are correct
B	A station transmitting SS emission must not cause harmful interference to other stations employing other authorized emissions
C	The transmission must not be used to obscure the meaning of any communication
D	The transmitting station must be in an area regulated by the FCC or in a country that permits SS emissions

8. - E2A09

What do the terms L band and S band specify regarding satellite communications?

Select	Answer
A	The 2 meter and 70 centimeter bands
B	The 23 centimeter and 13 centimeter bands
C	Which sideband to use
D	FM and Digital Store-and-Forward systems

9. - E2B05

Which of the following describes the use of vestigial sideband in analog fast-scan TV transmissions?

Select	Answer
A	Vestigial sideband reduces bandwidth while allowing for simple video detector circuitry
B	The vestigial sideband contains chroma information
C	Vestigial sideband provides high frequency emphasis to sharpen the picture
D	The vestigial sideband carries the audio information

10. - E2C10

Why might a DX station state that they are listening on another frequency?

Select	Answer
A	To improve operating efficiency by reducing interference
B	To separate the calling stations from the DX station
C	Because the DX station may be transmitting on a frequency that is prohibited to some responding stations
D	All these choices are correct

11. - E2D09

What type of modulation is used for JT65 contacts?

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

12. - E2E04

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

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

13. - E3A14

What is meant by circularly polarized electromagnetic waves?

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

14. - E3B03

What is the best time of day for transequatorial propagation?

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

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. - E4A08

Which of the following measures SWR?

Select	Answer
A	A Q meter
B	An ohmmeter
C	An antenna analyzer
D	A spectrum analyzer

17. - E4B10

Which of the following methods measures intermodulation distortion in an SSB transmitter?

Select	Answer
A	Modulate the transmitter using two RF signals having harmonically related frequencies and observe the RF output with a logic analyzer
B	Modulate the transmitter using two RF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer
C	Modulate the transmitter using two AF signals having harmonically related frequencies and observe the RF output with a peak reading wattmeter
D	Modulate the transmitter using two AF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer

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	-174 dBm
B	-155 dBm
C	-148 dBm
D	-164 dBm

19. - E4D04

Which of the following may reduce or eliminate intermodulation interference in a repeater caused by another transmitter operating in close proximity?

Select	Answer
A	Utilizing a Class D final amplifier
B	A band-pass filter in the feed line between the transmitter and receiver
C	Utilizing a Class C final amplifier
D	A properly terminated circulator at the output of the repeater's transmitter

20. - E4E09

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

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

21. - E5A09

How is the Q of an RLC parallel resonant circuit calculated?

Select	Answer
A	Reactance of either the inductance or capacitance multiplied by the resistance
B	Reactance of either the inductance or capacitance divided by the resistance
C	Resistance divided by the reactance of either the inductance or capacitance
D	Reactance of the inductance multiplied by the reactance of the capacitance

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. - E5C02

How are impedances described in polar coordinates?

Select	Answer
A	By real and imaginary parts
B	By X and R values
C	By Y and G values
D	By phase angle and magnitude

24. - E5D03

What is microstrip?

Select	Answer
A	Lightweight transmission line made of common zip cord
B	Miniature coax used for low power applications
C	Precision printed circuit conductors above a ground plane that provide constant impedance interconnects at microwave frequencies
D	Short lengths of coax mounted on printed circuit boards to minimize time delay between microwave circuits

25. - E6A07

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

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

26. - E6B08

Which of the following is a Schottky barrier diode?

Select	Answer
A	Metal-semiconductor junction
B	Electrolytic rectifier
C	PIN junction
D	Thermionic emission diode

27. - E6C09

What is a Programmable Logic Device (PLD)?

Select	Answer
A	A programmable collection of logic gates and circuits in a single integrated circuit
B	A type of transistor whose gain can be changed by digital logic circuits
C	A logic circuit that can be modified during use
D	Programmable equipment used for testing digital logic integrated circuits

28. - E6D13

What is the primary cause of inductor self-resonance?

Select	Answer
A	Inductive kickback
B	Inter-turn capacitance
C	Non-linear core hysteresis
D	The skin effect

29. - E6E11

What is a characteristic of DIP packaging used for integrated circuits?

Select	Answer
A	A total of two rows of connecting pins placed on opposite sides of the package (Dual In-line Package)
B	Package mounts in a direct inverted position
C	Low leakage doubly insulated package
D	Two chips in each package (Dual In Package)

30. - E6F03

What is the most common configuration of an optoisolator or optocoupler?

Select	Answer
A	An amplitude modulated helium-neon laser
B	A lens and a photomultiplier
C	An LED and a phototransistor
D	A frequency modulated helium-neon laser

31. - E7A06

What is a characteristic of a monostable multivibrator?

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

32. - E7B03

Which of the following components form the output of a class D amplifier circuit?

Select	Answer
A	A matched load resistor to prevent damage by switching transients
B	A low-pass filter to remove switching signal components
C	A temperature compensating load resistor to improve linearity
D	A high-pass filter to compensate for low gain at low frequencies

33. - E7C02

Which of the following is a property of a T-network with series capacitors and a parallel shunt inductor?

Select	Answer
A	It is a high-pass filter
B	It is a band-pass filter
C	It is a low-pass filter
D	It is a notch filter

34. - E7D05

Which of the following types of linear voltage regulator places a constant load on the unregulated voltage source?

Select	Answer
A	A series regulator
B	A shunt current source
C	A shunt regulator
D	A constant current source

35. - E7E01

Which of the following can be used to generate FM phone emissions?

Select	Answer
A	A reactance modulator on the final amplifier
B	A balanced modulator on the audio amplifier
C	A reactance modulator on the oscillator
D	A balanced modulator on the oscillator

36. - E7F04

What is a common method of generating an SSB signal using digital signal processing?

Select	Answer
A	A frequency synthesizer removes the unwanted sidebands
B	Mixing products are converted to voltages and subtracted by adder circuits
C	Varying quartz crystal characteristics emulated in digital form
D	Signals are combined in quadrature phase relationship

37. - E7G03

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

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

38. - E7H11

What are the major spectral impurity components of direct digital synthesizers?

Select	Answer
A	Spurious signals at discrete frequencies
B	Broadband noise
C	Nyquist limit noise
D	Digital conversion noise

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	Peak envelope power
D	Total harmonic distortion

40. - E8B04

What is the modulation index of an FM-phone signal having a maximum carrier deviation of plus or minus 6 kHz when modulated with a 2 kHz modulating frequency?

Select	Answer
A	3
B	2000
C	1/3
D	6000

41. - E8C04

What technique minimizes the bandwidth of a PSK31 signal?

Select	Answer
A	Use of trapezoidal data pulses
B	Use of sinusoidal data pulses
C	Reed-Solomon character encoding
D	Zero-sum character encoding

42. - E8D03

How does the spread spectrum technique of frequency hopping work?

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

43. - E9A05

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

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

44. - E9B06

What is the elevation angle of peak response in the antenna radiation pattern shown in Figure E9-2?

Select	Answer
A	25 degrees
B	75 degrees
C	45 degrees
D	7.5 degrees

45. - E9C11

How is the far-field elevation pattern of a vertically polarized antenna affected by being mounted over seawater versus soil?

Select	Answer
A	Additional higher vertical angle lobes will appear
B	The low-angle radiation decreases
C	Fewer vertical angle lobes will be present
D	The low-angle radiation increases

46. - E9D11

Which of the following conductors would be best for minimizing losses in a station's RF ground system?

Select	Answer
A	Resistive wire, such as spark plug wire
B	Solid wire
C	Wide flat copper strap
D	Stranded wire

47. - E9E02

What is the name of an antenna matching system that matches an unbalanced feed line to an antenna by feeding the driven element both at the center of the element and at a fraction of a wavelength to one side of center?

Select	Answer
A	The epsilon match
B	The stub match
C	The gamma match
D	The delta match

48. - E9F05

What is the approximate physical length of a solid polyethylene dielectric coaxial transmission line that is electrically 1/4 wavelength long at 14.1 MHz?

Select	Answer
A	4.3 meters
B	5.3 meters
C	10.6 meters
D	3.5 meters

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 resistance axis
C	The current axis
D	The voltage axis

50. - E9H06

What is the triangulation method of direction finding?

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

Figure E9-2

Figure E9-3