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

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1. - E0A03

Over what range of frequencies are the FCC human body RF exposure limits most restrictive?

Select	Answer
A	30 to 300 MHz
B	3 to 30 MHz
C	300 kHz to 3 MHz
D	300 to 3000 MHz

2. - E1A03

What is the maximum legal carrier frequency on the 20 meter band for transmitting USB AFSK digital signals having a 1 kHz bandwidth?

Select	Answer
A	14.100 MHz
B	14.070 MHz
C	14.349 MHz
D	14.149 MHz

3. - E1B01

Which of the following constitutes a spurious emission?

Select	Answer
A	An amateur station transmission made without the proper call sign identification
B	A signal transmitted to prevent its detection by any station other than the intended recipient
C	An emission outside the signal's necessary bandwidth that can be reduced or eliminated without affecting the information transmitted
D	Any transmitted signal that unintentionally interferes with another licensed radio station

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	5 minutes
C	10 minutes
D	30 seconds

5. - E1D03

What is a space telecommand station?

Select	Answer
A	An amateur station that receives telemetry from a satellite or balloon more than 50 kilometers above the surface of the Earth
B	An amateur station located on the surface of the Earth for communication with other Earth stations by means of Earth satellites
C	An amateur station that transmits communications to initiate, modify or terminate functions of a space station
D	An amateur station located in a satellite or a balloon more than 50 kilometers above the surface of the Earth

6. - E1E04

Which of the following best describes the Volunteer Examiner accreditation process?

Select	Answer
A	The procedure by which a VEC confirms that the VE applicant meets FCC requirements to serve as an examiner
B	The amateur operator applying must pass a VE examination administered by the FCC Enforcement Bureau
C	The prospective VE obtains accreditation from the FCC
D	Each General, Advanced and Amateur Extra Class operator is automatically accredited as a VE when the license is granted

7. - E1F08

Which of the following types of amateur station communications are prohibited?

Select	Answer
A	Communications that have political content, except as allowed by the Fairness Doctrine
B	Communications that have religious content
C	Communications in a language other than English
D	Communications transmitted for hire or material compensation, except as otherwise provided in the rules

8. - E2A13

Which of the following techniques is normally used by low Earth orbiting digital satellites to relay messages around the world?

Select	Answer
A	Node hopping
B	Store-and-forward
C	Multi-satellite relaying
D	Digipeating

9. - E2B07

What is the name of the signal component that carries color information in NTSC video?

Select	Answer
A	Chroma
B	Luminance
C	Hue
D	Spectral intensity

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	At the top of each band, usually in a segment reserved for contests
B	In the weak signal segment of the band, with most of the activity near the calling frequency
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. - E2D11

Which of the following data are used by the APRS network to communicate station location?

Select	Answer
A	Time and frequency
B	Radio direction finding spectrum analysis
C	Polar coordinates
D	Latitude and longitude

12. - E2E12

How do ALE stations establish contact?

Select	Answer
A	ALE radios monitor an internet site for the frequency they are being paged on
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 send a constant tone code to establish a frequency for future use

13. - E3A09

Which of the following frequency ranges is most suited for meteor scatter communications?

Select	Answer
A	1.8 MHz - 1.9 MHz
B	220 MHz - 450 MHz
C	28 MHz - 148 MHz
D	10 MHz - 14 MHz

14. - E3B01

What is transequatorial propagation?

Select	Answer
A	Propagation between a point on the equator and its antipodal point
B	Propagation between points located on the magnetic equator
C	Propagation between points at the same latitude
D	Propagation between two mid-latitude points at approximately the same distance north and south of the magnetic equator

15. - E3C11

What does VOACAP software model?

Select	Answer
A	HF propagation
B	VHF radio propagation
C	AC current and impedance
D	AC voltage and impedance

16. - E4A02

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

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

17. - E4B04

Which S parameter represents input port return loss or reflection coefficient (equivalent to VSWR)?

Select	Answer
A	S11
B	S22
C	S21
D	S12

18. - E4C12

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

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

19. - E4D10

What does a third-order intercept level of 40 dBm mean with respect to receiver performance?

Select	Answer
A	A pair of 1 mW input signals will produce a third-order intermodulation product that is 40 dB stronger than the input signal
B	Signals less than 40 dBm will not generate audible third-order intermodulation products
C	A pair of 40 dBm input signals will theoretically generate a third-order intermodulation product that has the same output amplitude as either of the input signals
D	The receiver can tolerate signals up to 40 dB above the noise floor without producing third-order intermodulation products

20. - E4E06

What is one type of electrical interference that might be caused by a nearby personal computer?

Select	Answer
A	A loud AC hum in the audio output of your station receiver
B	A clicking noise at intervals of a few seconds
C	A whining type noise that continually pulses off and on
D	The appearance of unstable modulated or unmodulated signals at specific frequencies

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. - E5B12

What is admittance?

Select	Answer
A	The turns ratio of a transformer
B	The inverse of Q factor
C	The inverse of impedance
D	The term for the gain of a field effect transistor

23. - E5C07

Where is the impedance of a pure resistance plotted on rectangular coordinates?

Select	Answer
A	On a line through the origin, slanted at 45 degrees
B	On the vertical axis
C	On the horizontal axis
D	On a horizontal line, offset vertically above the horizontal axis

24. - E5D05

What is the power factor of an RL circuit having a 30-degree phase angle between the voltage and the current?

Select	Answer
A	0.5
B	1.73
C	0.577
D	0.866

25. - E6A05

How does DC input impedance at the gate of a field-effect transistor compare with the DC input impedance of a bipolar transistor?

Select	Answer
A	They are both high impedance
B	An FET has lower input impedance
C	An FET has higher input impedance
D	They are both low impedance

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. - E6C04

Which of the following is an advantage of BiCMOS logic?

Select	Answer
A	It is immune to electrostatic damage
B	Its simplicity results in much less expensive devices than standard CMOS
C	It has the high input impedance of CMOS and the low output impedance of bipolar transistors
D	All these choices are correct

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

29. - E6E02

Which of the following device packages is a through-hole type?

Select	Answer
A	SOT
B	PLCC
C	DIP
D	Ball grid array

30. - E6F02

What happens to the conductivity of a photoconductive material when light shines on it?

Select	Answer
A	It becomes unstable
B	It stays the same
C	It decreases
D	It increases

31. - E7A11

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

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

32. - E7B10

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

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

33. - E7C06

What are the distinguishing features of an elliptical filter?

Select	Answer
A	Extremely flat response over its pass band with gradually rounded stop band corners
B	Gradual passband rolloff with extreme stop band ripple
C	Extremely sharp cutoff with one or more notches in the stop band
D	Gradual passband rolloff with minimal stop band ripple

34. - E7D11

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

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

35. - E7E02

What is the function of a reactance modulator?

Select	Answer
A	To produce AM signals by using an electrically variable inductance or capacitance
B	To produce AM signals by using an electrically variable resistance
C	To produce PM signals by using an electrically variable resistance
D	To produce PM or FM signals by using an electrically variable inductance or capacitance

36. - E7F06

What is the minimum number of bits required for an analog-to-digital converter to sample a signal with a range of 1 volt at a resolution of 1 millivolt?

Select	Answer
A	10 bits
B	6 bits
C	4 bits
D	8 bits

37. - E7G04

What is meant by the "op-amp input offset voltage"?

Select	Answer
A	The output voltage of the op-amp minus its input voltage
B	The potential between the amplifier input terminals of the op-amp in an open loop condition
C	The difference between the output voltage of the op-amp and the input voltage required in the immediately following stage
D	The differential input voltage needed to bring the open loop output voltage to zero

38. - E7H11

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

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

39. - E8A04

What is "dither" with respect to analog-to-digital converters?

Select	Answer
A	A small amount of noise added to the input signal to allow more precise representation of a signal over time
B	An error caused by irregular quantization step size
C	A method of decimation by randomly skipping samples
D	An abnormal condition where the converter cannot settle on a value to represent the signal

40. - E8B02

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

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

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. - E8D07

What is a common cause of overmodulation of AFSK signals?

Select	Answer
A	Bit errors in the modem
B	Excessive numbers of retries
C	Excessive transmit audio levels
D	Ground loops

43. - E9A06

What is the effective radiated power relative to a dipole of a repeater station with 200 watts transmitter power output, 4 dB feed line loss, 3.2 dB duplexer loss, 0.8 dB circulator loss, and 10 dBd antenna gain?

Select	Answer
A	300 watts
B	317 watts
C	126 watts
D	2000 watts

44. - E9B10

What is the principle of a Method of Moments analysis?

Select	Answer
A	A wire is modeled as a single sine-wave current generator
B	A wire is modeled as a single sine-wave voltage source
C	A wire is modeled as a series of segments, each having a uniform value of current
D	A wire is modeled as a series of segments, each having a distinct value of voltage across it

45. - E9C01

What is the radiation pattern of two 1/4-wavelength vertical antennas spaced 1/2-wavelength apart and fed 180 degrees out of phase?

Select	Answer
A	Cardioid
B	Omni-directional
C	A figure-8 broadside to the axis of the array
D	A figure-8 oriented along the axis of the array

46. - E9D05

What usually occurs if a Yagi antenna is designed solely for maximum forward gain?

Select	Answer
A	The SWR is reduced
B	The front-to-back ratio increases
C	The front-to-back ratio decreases
D	The frequency response is widened over the whole frequency band

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 gamma match
B	The delta match
C	The epsilon match
D	The stub match

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	The same as the characteristic impedance of the transmission line
C	The same as the generator output impedance
D	Very high impedance

49. - E9G11

How are the wavelength scales on a Smith chart calibrated?

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

50. - E9H02

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

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

Figure E7-1