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

2. - E1A09

What action or actions should you take if your digital message forwarding station inadvertently forwards a communication that violates FCC rules?

Select	Answer
A	All these choices are correct
B	Notify the nearest FCC Field Engineers office
C	Notify the originating station that the communication does not comply with FCC rules
D	Discontinue forwarding the communication as soon as you become aware of it

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 form FSD-15 must be submitted to the Department of the Interior
C	An Environmental Assessment must be submitted to the FCC
D	A letter of intent must be filed with the Environmental Protection Agency

4. - E1C03

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

Select	Answer
A	Under local control there is no control operator
B	Under automatic 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. - E1D05

What must be posted at the station location of a station being operated by telecommand on or within 50 km of the earth's surface?

Select	Answer
A	A label with the name, address, and telephone number of the control operator
B	All these choices are correct
C	A photocopy of the station license
D	A label with the name, address, and telephone number of the station licensee

6. - E1E07

What should a VE do if a candidate fails to comply with the examiner's instructions during an amateur operator license examination?

Select	Answer
A	Immediately terminate everyone's examination and close the session
B	Allow the candidate to complete the examination, but invalidate the results
C	Warn the candidate that continued failure to comply will result in termination of the examination
D	Immediately terminate the candidate's examination

7. - E1F07

When may an amateur station send a message to a business?

Select	Answer
A	When neither the amateur nor his or her employer has a pecuniary interest in the communications
B	When transmitting international third-party communications
C	When the total money involved does not exceed $25
D	When the control operator is employed by the FCC or another government agency

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

9. - E2B07

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

Select	Answer
A	Hue
B	Chroma
C	Luminance
D	Spectral intensity

10. - E2C05

What is the function of a DX QSL Manager?

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

11. - E2D02

Which of the following is a good technique for making meteor scatter contacts?

Select	Answer
A	Short transmissions with rapidly repeated call signs and signal reports
B	15-second timed transmission sequences with stations alternating based on location
C	All these choices are correct
D	Use of special digital modes

12. - E2E08

Which of the following HF digital modes can be used to transfer binary files?

Select	Answer
A	AMTOR
B	PACTOR
C	Hellschreiber
D	RTTY

13. - E3A06

What might help to restore contact when DX signals become too weak to copy across an entire HF band a few hours after sunset?

Select	Answer
A	Switch to a higher frequency HF band
B	Wait 90 minutes or so for the signal degradation to pass
C	Wait 24 hours before attempting another communication on the band
D	Switch to a lower frequency HF band

14. - E3B01

What is transequatorial propagation?

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

15. - E3C09

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

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

16. - E4A06

What is the effect of aliasing on a digital oscilloscope caused by setting the time base too slow?

Select	Answer
A	Calibration of the vertical scale is no longer valid
B	All signals will have a DC offset
C	Excessive blanking occurs, which prevents display of the signal
D	A false, jittery low-frequency version of the signal is displayed

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	Output impedance
D	Input impedance

18. - E4C09

Which of the following choices is a good reason for selecting a high frequency for the design of the IF in a superheterodyne HF or VHF communications receiver?

Select	Answer
A	Improved receiver noise figure
B	Fewer components in the receiver
C	Reduced drift
D	Easier for front-end circuitry to eliminate image responses

19. - E4D05

What transmitter frequencies would cause an intermodulation-product signal in a receiver tuned to 146.70 MHz when a nearby station transmits on 146.52 MHz?

Select	Answer
A	146.34 MHz and 146.61 MHz
B	146.88 MHz and 146.34 MHz
C	146.10 MHz and 147.30 MHz
D	173.35 MHz and 139.40 MHz

20. - E4E10

What might be the cause of a loud roaring or buzzing AC line interference that comes and goes at intervals?

Select	Answer
A	A defective doorbell or doorbell transformer inside a nearby residence
B	A malfunctioning illuminated advertising display
C	Arcing contacts in a thermostatically controlled device
D	All these choices are correct

21. - E5A10

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

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

22. - E5B08

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 100 ohms, R is 100 ohms, and XL is 75 ohms?

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

23. - E5C02

How are impedances described in polar coordinates?

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

24. - E5D14

What is reactive power?

Select	Answer
A	Power consumed in circuit Q
B	Wattless, nonproductive power
C	Power consumed in wire resistance in an inductor
D	Power lost because of capacitor leakage

25. - E6A11

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

Select	Answer
A	3
B	1
C	2
D	6

26. - E6B05

What characteristic of a PIN diode makes it useful as an RF switch?

Select	Answer
A	Low junction capacitance
B	Reverse bias controls its forward voltage drop
C	Extremely high reverse breakdown voltage
D	Ability to dissipate large amounts of power

27. - E6C03

What is tri-state logic?

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

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

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. - E6F11

What is the approximate open-circuit voltage produced by a fully illuminated silicon photovoltaic cell?

Select	Answer
A	12 V
B	1.5 V
C	0.1 V
D	0.5 V

31. - E7A05

Which of the following is a circuit that continuously alternates between two states without an external clock?

Select	Answer
A	T flip-flop
B	Monostable multivibrator
C	J-K flip-flop
D	Astable multivibrator

32. - E7B05

What can be done to prevent unwanted oscillations in an RF power amplifier?

Select	Answer
A	Tune the stage for maximum SWR
B	Install parasitic suppressors and/or neutralize the stage
C	Tune both the input and output for maximum power
D	Use a phase inverter in the output filter

33. - E7C08

Which of the following factors has the greatest effect on the bandwidth and response shape of a crystal ladder filter?

Select	Answer
A	The amplitude of the signals passing through the filter
B	The relative frequencies of the individual crystals
C	The DC voltage applied to the quartz crystal
D	The gain of the RF stage preceding the 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 constant current source
B	A shunt regulator
C	A shunt current source
D	A series regulator

35. - E7E03

What is a frequency discriminator stage in a FM receiver?

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

36. - E7F01

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

Select	Answer
A	Software is converted from source code to object code during operation of the receiver
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	Incoming RF is converted to a control voltage for a voltage controlled oscillator

37. - E7G09

What will be the output voltage of the circuit shown in Figure E7-3 if R1 is 1000 ohms, RF is 10,000 ohms, and 0.23 volts DC is applied to the input?

Select	Answer
A	-2.3 volts
B	0.23 volts
C	-0.23 volts
D	2.3 volts

38. - E7H13

Which of the following is a technique for providing highly accurate and stable oscillators needed for microwave transmission and reception?

Select	Answer
A	Use a GPS signal reference
B	Use a rubidium stabilized reference oscillator
C	Use a temperature-controlled high Q dielectric resonator
D	All these choices are correct

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

40. - E8B08

What describes Orthogonal Frequency Division Multiplexing?

Select	Answer
A	A digital modulation technique using subcarriers at frequencies chosen to avoid intersymbol interference
B	A frequency modulation technique that uses non-harmonically related frequencies
C	A digital mode for narrow-band, slow-speed transmissions
D	A bandwidth compression technique using Fourier transforms

41. - E8C05

What is the approximate bandwidth of a 13-WPM International Morse Code transmission?

Select	Answer
A	104 Hz
B	13 Hz
C	52 Hz
D	26 Hz

42. - E8D11

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

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

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	Soil conductivity
D	Distance from the transmitter

44. - E9B09

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

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

45. - E9C03

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

Select	Answer
A	A Figure-8 end-fire along the axis of the array
B	Cardioid
C	A Figure-8 broadside to the axis of the array
D	Omni-directional

46. - E9D07

What is an advantage of using top loading in a shortened HF vertical antenna?

Select	Answer
A	Greater structural strength
B	Higher losses
C	Lower Q
D	Improved radiation efficiency

47. - E9E10

Which of these choices is an effective way to match an antenna with a 100-ohm feed point impedance to a 50-ohm coaxial cable feed line?

Select	Answer
A	Insert a 1/2 wavelength piece of 300-ohm twinlead in series between the antenna terminals and the 50-ohm feed cable
B	Insert a 1/4-wavelength piece of 75-ohm coaxial cable transmission line in series between the antenna terminals and the 50-ohm feed cable
C	Connect a 1/4-wavelength open stub of 300-ohm twinlead in parallel with the coaxial feed line where it connects to the antenna
D	Connect a 1/2 wavelength shorted stub of 75-ohm cable in parallel with the 50-ohm cable where it attaches to the antenna

48. - E9F02

Which of the following has the biggest effect on the velocity factor of a transmission line?

Select	Answer
A	The center conductor resistivity
B	Dielectric materials used in the line
C	The termination impedance
D	The line length

49. - E9G06

On the Smith chart shown in Figure E9-3, what is the name for the large outer circle on which the reactance arcs terminate?

Select	Answer
A	Polar axis
B	Reactance axis
C	Prime axis
D	Impedance axis

50. - E9H04

What is an advantage of placing a grounded electrostatic shield around a small loop direction-finding antenna?

Select	Answer
A	It eliminates tracking errors caused by strong out-of-band signals
B	It increases signal strength by providing a better match to the feed line
C	It eliminates unbalanced capacitive coupling to the surroundings, improving the nulls
D	It adds capacitive loading, increasing the bandwidth of the antenna

Figure E6-1

Figure E7-3

Figure E9-3