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	Only with a carbon monoxide detector
C	Any ordinary smoke detector can be used
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	Discontinue forwarding the communication as soon as you become aware of it
D	Notify the originating station that the communication does not comply with FCC rules

3. - E1B01

Which of the following constitutes a spurious emission?

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

4. - E1C08

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

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

5. - E1D07

Which HF amateur bands have frequencies authorized for space stations?

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

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	Warn the candidate that continued failure to comply will result in termination of the examination
C	Immediately terminate the candidate's examination
D	Allow the candidate to complete the examination, but invalidate the results

7. - E1F04

Which of the following geographic descriptions approximately describes "Line A"?

Select	Answer
A	A line roughly parallel to and east of the U.S. Pacific coastline
B	A line roughly parallel to and north of the border between the U.S. and Mexico
C	A line roughly parallel to and west of the U.S. Atlantic coastline
D	A line roughly parallel to and south of the border between the U.S. and Canada

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

9. - E2B12

What signals SSTV receiving software to begin a new picture line?

Select	Answer
A	Specific tone frequencies
B	A two-tone signal
C	Specific tone amplitudes
D	Elapsed time

10. - E2C11

How should you generally identify your station when attempting to contact a DX station during a contest or in a pileup?

Select	Answer
A	Send your full call sign once or twice
B	Send only the last two letters of your call sign until you make contact
C	Send the call sign of the DX station three times, the words this is,then your call sign three times
D	Send your full call sign and grid square

11. - E2D05

What is one advantage of the JT65 mode?

Select	Answer
A	Uses only a 65 Hz bandwidth
B	The ability to decode signals which have a very low signal-to-noise ratio
C	Easily copied by ear if necessary
D	Permits fast-scan TV transmissions over narrow bandwidth

12. - E2E01

Which of the following types of modulation is common for data emissions below 30 MHz?

Select	Answer
A	Spread spectrum
B	Pulse modulation
C	DTMF tones modulating an FM signal
D	FSK

13. - E3A09

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

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

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 phase locked
D	They become depolarized

15. - E3C15

What might be indicated by a sudden rise in radio background noise across a large portion of the HF spectrum?

Select	Answer
A	Long-path propagation is likely
B	Increased transequatorial propagation is likely
C	A solar flare has occurred
D	A temperature inversion has occurred

16. - E4A08

Which of the following measures SWR?

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

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	125 watts
C	75 watts
D	25 watts

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

19. - E4D09

What is the purpose of the preselector in a communications receiver?

Select	Answer
A	To allow selection of the optimum RF amplifier device
B	To store often-used frequencies
C	To provide a range of AGC time constants
D	To increase rejection of signals outside the desired band

20. - E4E11

What could cause local AM broadcast band signals to combine to generate spurious signals in the MF or HF bands?

Select	Answer
A	One or more of the broadcast stations is transmitting an over-modulated signal
B	Your station receiver IF amplifier stage is defective
C	You are receiving skywave signals from a distant station
D	Nearby corroded metal joints are mixing and re-radiating the broadcast signals

21. - E5A01

What can cause the voltage across reactances in a series RLC circuit to be higher than the voltage applied to the entire circuit?

Select	Answer
A	Resistance
B	Resonance
C	Capacitance
D	Conductance

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 lagging the current
C	14 degrees with the voltage leading the current
D	76 degrees with the voltage leading the current

23. - E5C05

What is the name of the diagram used to show the phase relationship between impedances at a given frequency?

Select	Answer
A	Near field diagram
B	Venn diagram
C	Far field diagram
D	Phasor diagram

24. - E5D11

What is the power factor of an RL circuit having a 60-degree phase angle between the voltage and the current?

Select	Answer
A	1.73
B	1.414
C	0.866
D	0.5

25. - E6A10

In Figure E6-1, what is the schematic symbol for an N-channel dual-gate MOSFET?

Select	Answer
A	6
B	2
C	4
D	5

26. - E6B10

In Figure E6-2, what is the schematic symbol for a light-emitting diode?

Select	Answer
A	1
B	5
C	6
D	7

27. - E6C09

What is a Programmable Logic Device (PLD)?

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

28. - E6D02

What is the equivalent circuit of a quartz crystal?

Select	Answer
A	Motional inductance and loss resistance in series, paralleled with motional capacitance and a capacitor representing electrode and stray capacitance
B	Motional capacitance, motional inductance, loss resistance, and a capacitor representing electrode and stray capacitance all in series
C	Motional capacitance, motional inductance, loss resistance, and a capacitor representing electrode and stray capacitance all in parallel
D	Motional capacitance, motional inductance, and loss resistance in series, all in parallel with a shunt capacitor representing electrode and stray capacitance

29. - E6E08

How is power supplied to the most common type of MMIC?

Select	Answer
A	Directly to the bias voltage (VCC IN) lead
B	Through a capacitor and RF choke connected to the amplifier input lead
C	MMICs require no operating bias
D	Through a resistor and/or RF choke connected to the amplifier output lead

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. - E7A08

What logical operation does an OR gate perform?

Select	Answer
A	It only produces logic 0 at its output when all inputs are logic 1
B	It produces logic 1 at its output if all inputs are logic 0
C	It produces logic 1 at its output if any or all inputs are logic 1
D	It produces logic 0 at its output if all inputs are logic 1

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

33. - E7C04

How does an impedance-matching circuit transform a complex impedance to a resistive impedance?

Select	Answer
A	It introduces negative resistance to cancel the resistive part of impedance
B	It introduces transconductance to cancel the reactive part of impedance
C	It cancels the reactive part of the impedance and changes the resistive part to a desired value
D	Reactive currents are dissipated in matched resistances

34. - E7D15

What is the purpose of a step-start circuit in a high-voltage power supply?

Select	Answer
A	To compensate for variations of the incoming line voltage
B	To provide a dual-voltage output for reduced power applications
C	To allow for remote control of the power supply
D	To allow the filter capacitors to charge gradually

35. - E7E07

What is meant by the term "baseband" in radio communications?

Select	Answer
A	The unmodulated bandwidth of the transmitted signal
B	The lowest frequency band that the transmitter or receiver covers
C	The basic oscillator frequency in an FM transmitter that is multiplied to increase the deviation and carrier frequency
D	The frequency range occupied by a message signal prior to modulation

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	8 bits
B	4 bits
C	10 bits
D	6 bits

37. - E7G05

How can unwanted ringing and audio instability be prevented in an op-amp RC audio filter circuit?

Select	Answer
A	Restrict Q but increase gain
B	Increase both gain and Q
C	Restrict both gain and Q
D	Restrict gain but increase Q

38. - E7H09

What type of frequency synthesizer circuit uses a phase accumulator, lookup table, digital to analog converter, and a low-pass anti-alias filter?

Select	Answer
A	A diode-switching matrix synthesizer
B	A direct digital synthesizer
C	A hybrid synthesizer
D	A phase-locked loop synthesizer

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 square wave
C	A cosine wave
D	A sawtooth wave

40. - E8B06

What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus or minus 7.5 kHz when the maximum modulation frequency is 3.5 kHz?

Select	Answer
A	47
B	0.214
C	0.47
D	2.14

41. - E8C12

What factors affect the bandwidth of a transmitted CW signal?

Select	Answer
A	Modulation index and output power
B	All these choices are correct
C	Keying speed and shape factor (rise and fall time)
D	IF bandwidth and Q

42. - E8D01

Why are received spread spectrum signals resistant to interference?

Select	Answer
A	If interference is detected by the receiver it will signal the transmitter to change frequencies
B	The receiver is always equipped with a digital blanker
C	Signals not using the spread spectrum algorithm are suppressed in the receiver
D	The high power used by a spread spectrum transmitter keeps its signal from being easily overpowered

43. - E9A07

What is the effective isotropic radiated power of a repeater station with 200 watts transmitter power output, 2 dB feed line loss, 2.8 dB duplexer loss, 1.2 dB circulator loss, and 7 dBi antenna gain?

Select	Answer
A	252 watts
B	632 watts
C	63.2 watts
D	159 watts

44. - E9B10

What is the principle of a Method of Moments analysis?

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

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

46. - E9D05

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

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

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 epsilon match
C	The stub match
D	The delta match

48. - E9F04

What impedance does a 1/2-wavelength transmission line present to a generator when the line is shorted at the far end?

Select	Answer
A	Very high impedance
B	The same as the output impedance of the generator
C	The same as the characteristic impedance of the line
D	Very low impedance

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	Impedance axis
B	Prime axis
C	Polar axis
D	Reactance axis

50. - E9H02

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

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

Figure E6-1

Figure E6-2

Figure E9-3