US Amateur Radio - Amateur Extra (Element 4, 2016-2020) Practice Test

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1. - E1A08

If a station in a message forwarding system inadvertently forwards a message that is in violation of FCC rules, who is primarily accountable for the rules violation?

Select	Answer
A	The control operator of the originating station
B	The control operators of all the stations in the system
C	The control operators of all the stations in the system not authenticating the source from which they accept communications
D	The control operator of the packet bulletin board station

2. - E1B10

What frequencies are authorized to an amateur station operating under RACES rules?

Select	Answer
A	All amateur service frequencies authorized to the control operator
B	Specific local government channels
C	Military Auxiliary Radio System (MARS) channels
D	Specific segments in the amateur service MF, HF, VHF and UHF bands

3. - 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 a control operator is not required to be present at a control point
B	Under automatic control the control operator is not required to be present at the control point
C	Under automatic control there is no control operator
D	Under local control there is no control operator

4. - E1D03

What is a telecommand station in the amateur satellite service?

Select	Answer
A	An amateur station that transmits telemetry consisting of measurements of upper atmosphere
B	An amateur station that transmits communications to initiate, modify or terminate functions of a space station
C	An amateur station located on the Earth's surface for communication with other Earth stations by means of Earth satellites
D	An amateur station located more than 50 km above the Earth's surface

5. - E1E11

What must the VE team do if an examinee scores a passing grade on all examination elements needed for an upgrade or new license?

Select	Answer
A	Three VEs must certify that the examinee is qualified for the license grant and that they have complied with the administering VE requirements
B	Issue the examinee the new or upgrade license
C	Photocopy all examination documents and forward them to the FCC for processing
D	All these choices are correct

6. - E1F11

Which of the following best describes one of the standards that must be met by an external RF power amplifier if it is to qualify for a grant of FCC certification?

Select	Answer
A	It must exhibit a gain of 0 dB or less over its full output range
B	It must produce full legal output when driven by not more than 5 watts of mean RF input power
C	It must be capable of external RF switching between its input and output networks
D	It must satisfy the FCC's spurious emission standards when operated at the lesser of 1500 watts or its full output power

7. - E2A05

What do the letters in a satellite's mode designator specify?

Select	Answer
A	The polarization of uplink and downlink signals
B	The location of the ground control station
C	Power limits for uplink and downlink transmissions
D	The uplink and downlink frequency ranges

8. - E2B17

What is the approximate bandwidth of a slow-scan TV signal?

Select	Answer
A	600 Hz
B	6 MHz
C	2 MHz
D	3 kHz

9. - E2C05

What is the function of a DX QSL Manager?

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

10. - E2D08

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

Select	Answer
A	Acknowledgement
B	Disconnect
C	Connect
D	Unnumbered Information

11. - E2E03

How is the timing of JT65 contacts organized?

Select	Answer
A	Alternating transmissions at 1 minute intervals
B	Stations take turns on alternate days
C	It depends on the lunar phase
D	By exchanging ACK/NAK packets

12. - E3A15

What is an electromagnetic wave?

Select	Answer
A	A wave consisting of an electric field and a magnetic field oscillating at right angles to each other
B	A wave consisting of two magnetic fields at right angles to each other
C	A wave consisting of two electric fields at parallel right angles to each other
D	A wave of alternating current, in the core of an electromagnet

13. - E3B03

What is the best time of day for transequatorial propagation?

Select	Answer
A	Afternoon or early evening
B	Morning
C	Noon
D	Late at night

14. - E3C07

Which of the following descriptors indicates the greatest solar flare intensity?

Select	Answer
A	Class X
B	Class A
C	Class M
D	Class B

15. - E4A08

Which of the following instrument would be best for measuring the SWR of a beam antenna?

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

16. - E4B02

What is an advantage of using a bridge circuit to measure impedance?

Select	Answer
A	It can display results directly in Smith chart format
B	It is very precise in obtaining a signal null
C	It is relatively immune to drift in the signal generator source
D	It provides an excellent match under all conditions

17. - E4C17

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

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

18. - E4D09

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

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

19. - E4E05

How can noise from an electric motor be suppressed?

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

20. - E5A15

Which of the following can increase Q for inductors and capacitors?

Select	Answer
A	Lower self-resonant frequency
B	Lower reactance
C	Higher self-resonant frequency
D	Lower losses

21. - E5B03

What happens to the phase angle of a reactance when it is converted to a susceptance?

Select	Answer
A	It is unchanged
B	The sign is reversed
C	It is shifted by 90 degrees
D	The susceptance phase angle is the inverse of the reactance phase angle

22. - E5C16

Which point on Figure E5-2 best represents the impedance of a series circuit consisting of a 300 ohm resistor and a 19 picofarad capacitor at 21.200 MHz?

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

23. - E5D06

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

Select	Answer
A	In the same direction as the current
B	In a direction determined by the left-hand rule
C	In all directions; omni-directional
D	In a direction opposite to the current

24. - E6A16

What are the majority charge carriers in N-type semiconductor material?

Select	Answer
A	Free protons
B	Free neutrons
C	Free electrons
D	Holes

25. - E6B13

What type of bias is required for an LED to emit light?

Select	Answer
A	Zero bias
B	Reverse bias
C	Forward bias
D	Inductive bias

26. - E6C05

What is an advantage of CMOS logic devices over TTL devices?

Select	Answer
A	Immune to damage from static discharge
B	Differential output capability
C	Lower power consumption
D	Lower distortion

27. - 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

28. - E6E12

Why are high-power RF amplifier ICs and transistors sometimes mounted in ceramic packages?

Select	Answer
A	To provide a low-pass frequency response
B	Enhanced sensitivity to light
C	High-voltage insulating ability
D	Better dissipation of heat

29. - E6F07

What is a solid state relay?

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

30. - E7A08

What logical operation does an OR gate perform?

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

31. - E7B03

Which of the following components form the output of a class D amplifier circuit?

Select	Answer
A	A temperature compensating load resistor to improve linearity
B	A high-pass filter to compensate for low gain at low frequencies
C	A low-pass filter to remove switching signal components
D	A matched load resistor to prevent damage by switching transients

32. - E7C04

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

Select	Answer
A	It cancels the reactive part of the impedance and changes the resistive part to a desired value
B	Network resistances are substituted for load resistances and reactances are matched to the resistances
C	It introduces transconductance to cancel the reactive part of impedance
D	It introduces negative resistance to cancel the resistive part of impedance

33. - E7D03

What device is typically used as a stable reference voltage in a linear voltage regulator?

Select	Answer
A	An SCR
B	A varactor diode
C	A tunnel diode
D	A Zener diode

34. - E7E06

Why is de-emphasis commonly used in FM communications receivers?

Select	Answer
A	For compatibility with transmitters using phase modulation
B	For higher efficiency
C	To reduce impulse noise reception
D	To remove third-order distortion products

35. - E7F16

How might the sampling rate of an existing digital signal be adjusted by a factor of 3/4?

Select	Answer
A	Interpolate by a factor of three, then decimate by a factor of four
B	Add 3 to each input value and subtract 4 from each output value
C	Change the gain by a factor of 3/4
D	Multiply each sample value by a factor of 3/4

36. - E7G06

Which of the following is the most appropriate use of an op-amp active filter?

Select	Answer
A	As a high-pass filter used to block RFI at the input to receivers
B	As an audio filter in a receiver
C	As a low-pass filter used between a transmitter and a transmission line
D	For smoothing power supply output

37. - E7H02

Which describes a microphonic?

Select	Answer
A	An IC used for amplifying microphone signals
B	Changes in oscillator frequency due to mechanical vibration
C	Excess loading of the microphone by an oscillator
D	Distortion caused by RF pickup on the microphone cable

38. - E8A10

What is the purpose of a low pass filter used in conjunction with a digital-to-analog converter?

Select	Answer
A	All of these choices are correct
B	Improve accuracy by removing out of sequence codes from the input
C	Remove harmonics from the output caused by the discrete analog levels generated
D	Lower the input bandwidth to increase the effective resolution

39. - E8B04

What is the modulation index of an FM-phone signal having a maximum carrier deviation of plus or minus 6 kHz when modulated with a 2 kHz modulating frequency?

Select	Answer
A	2000
B	1/3
C	6000
D	3

40. - E8C04

What technique is used to minimize the bandwidth requirements of a PSK31 signal?

Select	Answer
A	Zero-sum character encoding
B	Use of trapezoidal data pulses
C	Reed-Solomon character encoding
D	Use of sinusoidal data pulses

41. - 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	The high power used by a spread spectrum transmitter keeps its signal from being easily overpowered
D	Signals not using the spread spectrum algorithm are suppressed in the receiver

42. - 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	Take-off angle
B	The standing wave ratio
C	Soil conductivity
D	Distance from the transmitter

43. - E9B05

What type of antenna pattern over real ground is shown in Figure E9-2?

Select	Answer
A	Azimuth
B	Polarization
C	Elevation
D	Radiation resistance

44. - E9C02

What is the radiation pattern of two 1/4 wavelength vertical antennas spaced 1/4 wavelength apart and fed 90 degrees out of phase?

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

45. - E9D02

How can linearly polarized Yagi antennas be used to produce circular polarization?

Select	Answer
A	Stack two Yagis fed in phase to form an array with the respective elements in parallel planes
B	Arrange two Yagis perpendicular to each other with the driven elements at the same point on the boom fed 90 degrees out of phase
C	Arrange two Yagis collinear to each other with the driven elements fed 180 degrees out of phase
D	Stack two Yagis fed 90 degrees out of phase to form an array with the respective elements in parallel planes

46. - E9E06

What is the equivalent lumped-constant network for a hairpin matching system of a 3-element Yagi?

Select	Answer
A	Pi-network
B	A shunt inductor
C	A series capacitor
D	Pi-L-network

47. - 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	The same as the generator output impedance
B	Very low impedance
C	Very high impedance
D	The same as the characteristic impedance of the transmission line

48. - E9G02

What type of coordinate system is used in a Smith chart?

Select	Answer
A	Resistance lines and reactance chords
B	Resistance circles and reactance arcs
C	Voltage circles and current arcs
D	Voltage lines and current chords

49. - E9H01

When constructing a Beverage antenna, which of the following factors should be included in the design to achieve good performance at the desired frequency?

Select	Answer
A	Its overall length must not exceed 1/4 wavelength
B	It should be one or more wavelengths long
C	It must be mounted more than 1 wavelength above ground
D	It should be configured as a four-sided loop

50. - 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	By the odor
D	Only with a carbon monoxide detector

Figure E5-2

Figure E9-2