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

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1. - E0A08

What does SAR measure?

Select	Answer
A	Signal Amplification Rating
B	Synthetic Aperture Ratio of the human body
C	The rate of RF energy reflected from stationary terrain
D	The rate at which RF energy is absorbed by the body

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 highest frequency of the channel
C	At the center frequency of the channel
D	At the lowest frequency of the channel

3. - E1B08

What limitations may the FCC place on an amateur station if its signal causes interference to domestic broadcast reception, assuming that the receivers involved are of good engineering design?

Select	Answer
A	The amateur station must cease operation on all frequencies above 30 MHz
B	The amateur station must cease operation
C	The amateur station must cease operation on all frequencies below 30 MHz
D	The amateur station must avoid transmitting during certain hours on frequencies that cause the interference

4. - E1C03

How do the control operator responsibilities of a station under automatic control differ from one under local control?

Select	Answer
A	Under automatic control there is no control operator
B	Under local control there is no control operator
C	Under local control a control operator is not required to be present at a control point
D	Under automatic control the control operator is not required to be present at the control point

5. - E1D10

Which amateur stations are eligible to be telecommand stations of space stations (subject to the privileges of the class of operator license held by the control operator of the station)?

Select	Answer
A	Any amateur station so designated by the ITU
B	All these choices are correct
C	Any amateur station so designated by the space station licensee
D	Any amateur station designated by NASA

6. - E1E12

What must the VE team do with the application form if the examinee does not pass the exam?

Select	Answer
A	Maintain the application form with the VEC's records
B	Return the application document to the examinee
C	Destroy the application form
D	Send the application form to the FCC and inform the FCC of the grade

7. - E1F10

Who may be the control operator of an auxiliary station?

Select	Answer
A	Only Amateur Extra Class operators
B	Only General, Advanced or Amateur Extra Class operators
C	Any licensed amateur operator
D	Only Technician, General, Advanced or Amateur Extra Class operators

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 reduced to I and Q components and the Q component is filtered out
C	The signal is passed through a mixer and the difference rather than the sum is transmitted
D	The signal is passed through a non-linear filter

9. - E2B05

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

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

10. - E2C01

What indicator is required to be used by U.S.-licensed operators when operating a station via remote control and the remote transmitter is located in the U.S.?

Select	Answer
A	/R# where # is the district of the remote station
B	No additional indicator is required
C	/ followed by the ARRL Section of the remote station
D	/ followed by the USPS two-letter abbreviation for the state in which the remote station is located

11. - E2D11

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

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

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. - E3A11

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

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

14. - E3B05

Which amateur bands typically support long-path propagation?

Select	Answer
A	Only 30 meters to 10 meters
B	6 meters to 2 meters
C	160 meters to 10 meters
D	Only 160 meters to 40 meters

15. - E3C06

By how much does the VHF/UHF radio horizon distance exceed the geometric horizon?

Select	Answer
A	By approximately twice the distance
B	By approximately 50 percent of the distance
C	By approximately four times the distance
D	By approximately 15 percent of the distance

16. - E4A09

Which of the following is good practice when using an oscilloscope probe?

Select	Answer
A	Never use a DC-coupled probe to measure an AC circuit
B	Keep the signal ground connection of the probe as short as possible
C	Never use a high-impedance probe to measure a low-impedance circuit
D	All these choices are correct

17. - E4B05

What three test loads are used to calibrate an RF vector network analyzer?

Select	Answer
A	50 ohms, 75 ohms, and 90 ohms
B	Short circuit, open circuit, and resonant circuit
C	Short circuit, open circuit, and 50 ohms
D	50 ohms through 1/8 wavelength, 1/4 wavelength, and 1/2 wavelength of coaxial cable

18. - E4C01

What is an effect of excessive phase noise in a receiver's local oscillator?

Select	Answer
A	It limits the receiver's ability to receive strong signals
B	It can affect the receiver's frequency calibration
C	It decreases receiver third-order intercept point
D	It can combine with strong signals on nearby frequencies to generate interference

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

20. - E4E05

How can radio frequency interference from an AC motor be suppressed?

Select	Answer
A	By installing a brute-force AC-line filter in series with the motor leads
B	By installing a bypass capacitor in series with the motor leads
C	By installing a high-pass filter in series with the motor's power leads
D	By using a ground-fault current interrupter in the circuit used to power the motor

21. - E5A02

What is resonance in an LC or RLC circuit?

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

22. - E5B10

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

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

23. - E5C06

What does the impedance 50-j25 represent?

Select	Answer
A	50 ohms resistance in series with 25 ohms capacitive reactance
B	25 ohms resistance in series with 50 ohms inductive reactance
C	25 ohms resistance in series with 50 ohms capacitive reactance
D	50 ohms resistance in series with 25 ohms inductive reactance

24. - E5D13

How many watts are consumed in a circuit consisting of a 100-ohm resistor in series with a 100-ohm inductive reactance drawing 1 ampere?

Select	Answer
A	70.7 watts
B	141.4 watts
C	100 watts
D	200 watts

25. - E6A03

Why does a PN-junction diode not conduct current when reverse biased?

Select	Answer
A	Excess holes in P-type material combine with the electrons in N-type material, converting the entire diode into an insulator
B	Only N-type semiconductor material can conduct current
C	Only P-type semiconductor material can conduct current
D	Holes in P-type material and electrons in the N-type material are separated by the applied voltage, widening the depletion region

26. - E6B07

What is the failure mechanism when a junction diode fails due to excessive current?

Select	Answer
A	Insufficient forward voltage
B	Excessive inverse voltage
C	Excessive junction temperature
D	Charge carrier depletion

27. - E6C07

What best describes a pull-up or pull-down resistor?

Select	Answer
A	A resistor that ensures that an oscillator frequency does not drift
B	A resistor connected to the positive or negative supply line used to establish a voltage when an input or output is an open circuit
C	A resistor in a keying circuit used to reduce key clicks
D	A resistor connected to an op-amp output that prevents signals from exceeding the power supply voltage

28. - E6D03

Which of the following is an aspect of the piezoelectric effect?

Select	Answer
A	Mechanical deformation of material by the application of a voltage
B	Generation of electrical energy in the presence of light
C	Increased conductivity in the presence of light
D	Mechanical deformation of material by the application of a magnetic field

29. - E6E03

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

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

30. - E6F07

What is a solid-state relay?

Select	Answer
A	A device that uses semiconductors to implement the functions of an electromechanical relay
B	A semiconductor passive delay line
C	A relay using transistors to drive the relay coil
D	A mechanical relay that latches in the on or off state each time it is pulsed

31. - E7A03

Which of the following can divide the frequency of a pulse train by 2?

Select	Answer
A	A multiplexer
B	A flip-flop
C	An XOR gate
D	An OR gate

32. - E7B04

Where on the load line of a Class A common emitter amplifier would bias normally be set?

Select	Answer
A	At a point where the bias resistor equals the load resistor
B	Approximately halfway between saturation and cutoff
C	At a point where the load line intersects the zero bias current curve
D	Where the load line intersects the voltage axis

33. - E7C06

What are the distinguishing features of an elliptical filter?

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

34. - E7D05

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

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

35. - E7E03

What is a frequency discriminator stage in a FM receiver?

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

36. - E7F03

What type of digital signal processing filter is used to generate an SSB signal?

Select	Answer
A	A Hilbert-transform filter
B	An elliptical filter
C	An adaptive filter
D	A notch filter

37. - E7G06

What is the gain-bandwidth of an operational amplifier?

Select	Answer
A	The frequency at which the open-loop gain of the amplifier equals one
B	The gain of the amplifier at a filter's cutoff frequency
C	The maximum frequency for a filter circuit using that type of amplifier
D	The frequency at which the amplifier's offset voltage is zero

38. - E7H01

What are three oscillator circuits used in amateur radio equipment?

Select	Answer
A	Pierce, Fenner and Beane
B	Taft, Pierce and negative feedback
C	Taft, Hartley and Pierce
D	Colpitts, Hartley and Pierce

39. - E8A02

Which of the following is a type of analog-to-digital conversion?

Select	Answer
A	Phase reversal
B	Harmonic regeneration
C	Successive approximation
D	Level shifting

40. - E8B07

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

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

41. - E8C06

What is the bandwidth of a 170-hertz shift, 300-baud ASCII transmission?

Select	Answer
A	0.1 Hz
B	1.0 kHz
C	0.5 kHz
D	0.3 kHz

42. - E8D11

What is one advantage of using ASCII code for data communications?

Select	Answer
A	It uses one character as a shift code to send numeric and special characters
B	It includes built-in error correction features
C	It is possible to transmit both upper and lower case text
D	It contains fewer information bits per character than any other code

43. - E9A08

What is antenna bandwidth?

Select	Answer
A	The frequency range over which an antenna satisfies a performance requirement
B	Antenna length divided by the number of elements
C	The angle formed between two imaginary lines drawn through the element ends
D	The angle between the half-power radiation points

44. - E9B08

What is the far field of an antenna?

Select	Answer
A	The region of the ionosphere where radiated power is not refracted
B	The region where radiated field strengths are constant
C	The region where radiated power dissipates over a specified time period
D	The region where the shape of the antenna pattern is independent of distance

45. - E9C14

How does the performance of a horizontally polarized antenna mounted on the side of a hill compare with the same antenna mounted on flat ground?

Select	Answer
A	The horizontal beamwidth increases in the uphill direction
B	The horizontal beamwidth decreases in the downhill direction
C	The main lobe takeoff angle increases in the downhill direction
D	The main lobe takeoff angle decreases in the downhill direction

46. - E9D03

Where should a high Q loading coil be placed to minimize losses in a shortened vertical antenna?

Select	Answer
A	At a voltage node
B	Near the center of the vertical radiator
C	As close to the transmitter as possible
D	As low as possible on the vertical radiator

47. - E9E08

What is a use for a Wilkinson divider?

Select	Answer
A	It divides the operating frequency of a transmitter signal so it can be used on a lower frequency band
B	It is used to feed low-impedance loads from a high-impedance source
C	It is used to feed high-impedance antennas from a low-impedance source
D	It is used to divide power equally between two 50-ohm loads while maintaining 50-ohm input impedance

48. - E9F06

What is the approximate physical length of an air-insulated, parallel conductor transmission line that is electrically 1/2 wavelength long at 14.10 MHz?

Select	Answer
A	8.5 meters
B	7.0 meters
C	10.6 meters
D	13.3 meters

49. - E9G08

What is the process of normalization with regard to a Smith chart?

Select	Answer
A	Reassigning reactance values with regard to the resistance axis
B	Reassigning resistance values with regard to the reactance axis
C	Reassigning impedance values with regard to the prime center
D	Reassigning prime center with regard to the reactance axis

50. - E9H07

Why is RF attenuation used when direction-finding?

Select	Answer
A	To prevent receiver overload which reduces pattern nulls
B	To increase receiver sensitivity
C	To compensate for isotropic directivity and the antenna effect of feed lines
D	To narrow the receiver bandwidth