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

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1. - E0A07

How may dangerous levels of carbon monoxide from an emergency generator be detected?

Select	Answer
A	Any ordinary smoke detector can be used
B	By the yellowish appearance of the gas
C	Only with a carbon monoxide detector
D	By the odor

2. - E1A10

If an amateur station is installed aboard a ship or aircraft, what condition must be met before the station is operated?

Select	Answer
A	The amateur station must have a power supply that is completely independent of the main ship or aircraft power supply
B	The amateur operator must have an FCC Marine or Aircraft endorsement on his or her amateur license
C	Its operation must be approved by the master of the ship or the pilot in command of the aircraft
D	The amateur station operator must agree not to transmit when the main radio of the ship or aircraft is in use

3. - E1B06

Which of the following additional rules apply if you are installing an amateur station antenna at a site at or near a public use airport?

Select	Answer
A	You must file an Environmental Impact Statement with the EPA before construction begins
B	You must submit engineering drawings to the FAA
C	You must obtain a construction permit from the airport zoning authority
D	You may have to notify the Federal Aviation Administration and register it with the FCC as required by Part 17 of the FCC rules

4. - E1C07

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

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

5. - E1D12

Which of the following amateur stations may transmit one-way communications?

Select	Answer
A	A message forwarding station or automatically controlled digital station
B	All these choices are correct
C	A local repeater or linked repeater station
D	A space station, beacon station, or telecommand station

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. - E1F09

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

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

8. - E2A10

What type of satellite appears to stay in one position in the sky?

Select	Answer
A	Geomagnetic
B	HEO
C	LEO
D	Geostationary

9. - E2B06

What is vestigial sideband modulation?

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

10. - E2C06

During a VHF/UHF contest, in which band segment would you expect to find the highest level of SSB or CW activity?

Select	Answer
A	In the weak signal segment of the band, with most of the activity near the calling frequency
B	At the top of each band, usually in a segment reserved for contests
C	In the middle of the band, usually 25 kHz above the national calling frequency
D	In the middle of each band, usually on the national calling frequency

11. - E2D08

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

Select	Answer
A	Acknowledgement
B	Connect
C	Unnumbered Information
D	Disconnect

12. - E2E12

How do ALE stations establish contact?

Select	Answer
A	ALE radios send a constant tone code to establish a frequency for future use
B	ALE constantly scans a list of frequencies, activating the radio when the designated call sign is received
C	ALE radios activate when they hear their signal echoed by back scatter
D	ALE radios monitor an internet site for the frequency they are being paged on

13. - E3A11

What is a typical range for tropospheric propagation of microwave signals?

Select	Answer
A	2500 miles
B	1200 miles
C	100 miles to 300 miles
D	10 miles to 50 miles

14. - E3B07

What happens to linearly polarized radio waves that split into ordinary and extraordinary waves in the ionosphere?

Select	Answer
A	They become elliptically polarized
B	They are bent toward the magnetic poles
C	They become depolarized
D	They become phase locked

15. - E3C10

What does the 304A solar parameter measure?

Select	Answer
A	UV emissions at 304 angstroms, correlated to the solar flux index
B	The ratio of x-ray flux to radio flux, correlated to sunspot number
C	The solar wind velocity at 304 degrees from the solar equator, correlated to solar activity
D	The solar emission at 304 GHz, correlated to x-ray flare levels

16. - E4A05

What is the purpose of the prescaler function on a frequency counter?

Select	Answer
A	It divides a higher frequency signal so a low-frequency counter can display the input frequency
B	It amplifies low-level signals for more accurate counting
C	It multiplies a higher frequency signal so a low-frequency counter can display the operating frequency
D	It prevents oscillation in a low-frequency counter circuit

17. - E4B06

How much power is being absorbed by the load when a directional power meter connected between a transmitter and a terminating load reads 100 watts forward power and 25 watts reflected power?

Select	Answer
A	100 watts
B	75 watts
C	125 watts
D	25 watts

18. - E4C08

An SDR receiver is overloaded when input signals exceed what level?

Select	Answer
A	The maximum count value of the analog-to-digital converter
B	One-half the maximum sampling buffer size
C	One-half the maximum sample rate
D	The reference voltage of the analog-to-digital converter

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	Adjacent channel interference
B	Intermodulation
C	Neutralization
D	Amplifier desensitization

20. - E4E08

What current flows equally on all conductors of an unshielded multi-conductor cable?

Select	Answer
A	Reactive current only
B	Common-mode current
C	Return current
D	Differential-mode current

21. - E5A02

What is resonance in an LC or RLC circuit?

Select	Answer
A	The frequency at which the reactive impedance equals the resistive impedance
B	The lowest frequency that will pass current
C	The highest frequency that will pass current
D	The frequency at which the capacitive reactance equals the inductive reactance

22. - E5B11

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 25 ohms, R is 100 ohms, and XL is 50 ohms?

Select	Answer
A	14 degrees with the voltage leading the current
B	14 degrees with the voltage lagging the current
C	76 degrees with the voltage lagging the current
D	76 degrees with the voltage leading the current

23. - E5C11

Which point in Figure E5-1 best represents the impedance of a series circuit consisting of a 300-ohm resistor and an 18-microhenry inductor at 3.505 MHz?

Select	Answer
A	Point 8
B	Point 7
C	Point 1
D	Point 3

24. - E5D06

In what direction is the magnetic field oriented about a conductor in relation to the direction of electron flow?

Select	Answer
A	In a direction opposite to the current
B	In all directions; omni-directional
C	In a circle around the conductor
D	In the same direction as the current

25. - E6A06

What is the beta of a bipolar junction transistor?

Select	Answer
A	The frequency at which the current gain is reduced to 0.707
B	The breakdown voltage of the base to collector junction
C	The switching speed
D	The change in collector current with respect to base current

26. - E6B02

What is an important characteristic of a Schottky diode as compared to an ordinary silicon diode when used as a power supply rectifier?

Select	Answer
A	Longer carrier retention time
B	Much higher reverse voltage breakdown
C	Less forward voltage drop
D	More constant reverse avalanche voltage

27. - E6C09

What is a Programmable Logic Device (PLD)?

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

28. - E6D04

Which materials are commonly used as a core in an inductor?

Select	Answer
A	Cobalt and aluminum
B	Ferrite and brass
C	Teflon and Delrin
D	Polystyrene and polyethylene

29. - E6E07

What type of transmission line is used for connections to MMICs?

Select	Answer
A	Microstrip
B	Circular waveguide
C	Miniature coax
D	Parallel wire

30. - E6F03

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

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

31. - E7A02

What is the function of a decade counter?

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

32. - E7B13

Which of the following describes an emitter follower (or common collector) amplifier?

Select	Answer
A	An OR circuit with only one emitter used for output
B	A differential amplifier with both inputs fed to the emitter of the input transistor
C	An amplifier with a low impedance output that follows the base input voltage
D	A two-transistor amplifier with the emitters sharing a common bias resistor

33. - E7C01

How are the capacitors and inductors of a low-pass filter Pi-network arranged between the network's input and output?

Select	Answer
A	Two capacitors are in series between the input and output, and an inductor is connected between the two capacitors and ground
B	A capacitor is connected between the input and ground, another capacitor is connected between the output and ground, and an inductor is connected between input and output
C	Two inductors are in series between the input and output, and a capacitor is connected between the two inductors and ground
D	An inductor is connected between the input and ground, another inductor is connected between the output and ground, and a capacitor is connected between the input and output

34. - E7D11

What is the function of the pass transistor in a linear voltage regulator circuit?

Select	Answer
A	Maintains nearly constant output voltage over a wide range of load current
B	Provides a stable input impedance over a wide range of source voltage
C	Permits a wide range of output voltage settings
D	Maintains nearly constant output impedance over a wide range of load current

35. - E7E04

What is one way a single-sideband phone signal can be generated?

Select	Answer
A	By driving a product detector with a DSB signal
B	By using a reactance modulator followed by a mixer
C	By using a balanced modulator followed by a filter
D	By using a loop modulator followed by a mixer

36. - E7F13

What is the function of taps in a digital signal processing filter?

Select	Answer
A	To reduce excess signal pressure levels
B	Provide incremental signal delays for filter algorithms
C	Select the point at which baseband signals are generated
D	Provide access for debugging software

37. - E7G12

What is an operational amplifier?

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

38. - E7H03

How is positive feedback supplied in a Hartley oscillator?

Select	Answer
A	Through a tapped coil
B	Through a capacitive divider
C	Through link coupling
D	Through a neutralizing capacitor

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 square wave
C	A sawtooth wave
D	A sine wave

40. - E8B09

What is deviation ratio?

Select	Answer
A	The ratio of the maximum carrier frequency deviation to the highest audio modulating frequency
B	The ratio of the highest audio modulating frequency to the average audio modulating frequency
C	The ratio of the carrier center frequency to the audio modulating frequency
D	The ratio of the audio modulating frequency to the center carrier frequency

41. - E8C03

Why should phase-shifting of a PSK signal be done at the zero crossing of the RF signal?

Select	Answer
A	To minimize bandwidth
B	All these choices are correct
C	To improve carrier suppression
D	To simplify modulation

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

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	Take-off angle
C	Distance from the transmitter
D	Soil conductivity

44. - E9B09

What type of computer program technique is commonly used for modeling antennas?

Select	Answer
A	Method of Moments
B	Mutual impedance analysis
C	Calculus differentiation with respect to physical properties
D	Graphical analysis

45. - E9C07

What is the approximate feed point impedance at the center of a two-wire folded dipole antenna?

Select	Answer
A	72 ohms
B	300 ohms
C	450 ohms
D	50 ohms

46. - E9D06

What happens to the SWR bandwidth when one or more loading coils are used to resonate an electrically short antenna?

Select	Answer
A	It is unchanged if the loading coil is located at the feed point
B	It is decreased
C	It is unchanged if the loading coil is located at a voltage maximum point
D	It is increased

47. - E9E11

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

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

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	5.3 meters
B	10.6 meters
C	4.3 meters
D	3.5 meters

49. - E9G10

What do the arcs on a Smith chart represent?

Select	Answer
A	SWR
B	Points with constant reactance
C	Points with constant resistance
D	Frequency

50. - E9H06

What is the triangulation method of direction finding?

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

Figure E5-1