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

Logging in (or registering) will help the system to select questions that you need to focus on.

1. - E1A04

With your transceiver displaying the carrier frequency of phone signals, you hear a DX station calling CQ on 3.601 MHz LSB. Is it legal to return the call using lower sideband on the same frequency?

Select	Answer
A	No, the sideband will extend beyond the edge of the phone band segment
B	Yes, because the DX station initiated the contact
C	No, U.S. stations are not permitted to use phone emissions below 3.610 MHz
D	Yes, because the displayed frequency is within the 75 meter phone band segment

2. - E1B10

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

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

3. - E1C10

What types of amateur stations may automatically retransmit the radio signals of other amateur stations?

Select	Answer
A	Only auxiliary, beacon or space stations
B	Only auxiliary, repeater or space stations
C	Only earth stations, repeater stations or model craft
D	Only beacon, repeater or space stations

4. - E1D06

Which of the following is a requirement of a space station?

Select	Answer
A	All of these choices are correct
B	The space station must cease all transmissions after 5 years
C	The space station must be capable of changing its orbit whenever such a change is ordered by NASA
D	The space station must be capable of terminating transmissions by telecommand when directed by the FCC

5. - E1E13

Which of these choices is an acceptable method for monitoring the applicants if a VEC opts to conduct an exam session remotely?

Select	Answer
A	Use a real-time video link and the Internet to connect the exam session to the observing VEs
B	Have each applicant sign an affidavit stating that all session rules were followed
C	The exam proctor observes the applicants and reports any violations
D	Record the exam session on video tape for later review by the VE team

6. - E1F05

Amateur stations may not transmit in which of the following frequency segments if they are located in the contiguous 48 states and north of Line A?

Select	Answer
A	53 MHz - 54 MHz
B	420 MHz - 430 MHz
C	440 MHz - 450 MHz
D	222 MHz - 223 MHz

7. - E2A07

Which of the following types of signals can be relayed through a linear transponder?

Select	Answer
A	PSK and Packet
B	SSB and SSTV
C	All of these choices are correct
D	FM and CW

8. - E2B11

What is the function of the Vertical Interval Signaling (VIS) code sent as part of an SSTV transmission?

Select	Answer
A	To lock the color burst oscillator in color SSTV images
B	To identify the SSTV mode being used
C	To provide vertical synchronization
D	To identify the call sign of the station transmitting

9. - E2C06

During a VHF/UHF contest, in which band segment would you expect to find the highest level of activity?

Select	Answer
A	In the weak signal segment of the band, with most of the activity near the calling frequency
B	At the top of each band, usually in a segment reserved for contests
C	In the middle of each band, usually on the national calling frequency
D	In the middle of the band, usually 25 kHz above the national calling frequency

10. - E2D07

What digital protocol is used by APRS?

Select	Answer
A	802.11
B	AX.25
C	PACTOR
D	AMTOR

11. - E2E08

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

Select	Answer
A	RTTY
B	AMTOR
C	Hellschreiber
D	PACTOR

12. - E3A06

Which of the following is required for microwave propagation via rain scatter?

Select	Answer
A	All of these choices are correct
B	The rain must be within radio range of both stations
C	Rain droplets must be within the E layer
D	Rain droplets must be electrically charged

13. - E3B04

What is meant by the terms extraordinary and ordinary waves?

Select	Answer
A	Extraordinary waves describe rare long skip propagation compared to ordinary waves which travel shorter distances
B	Independent waves created in the ionosphere that are elliptically polarized
C	Refracted rays and reflected waves
D	Long path and short path waves

14. - E3C09

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

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

15. - E4A06

What is the effect of aliasing in a digital or computer-based oscilloscope?

Select	Answer
A	All signals will have a DC offset
B	False triggering occurs
C	Calibration of the vertical scale is no longer valid
D	False signals are displayed

16. - E4B02

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

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

17. - E4C01

What is an effect of excessive phase noise in the local oscillator section of a receiver?

Select	Answer
A	It can cause strong signals on nearby frequencies to interfere with reception of weak signals
B	It decreases receiver third-order intermodulation distortion dynamic range
C	It reduces receiver sensitivity
D	It limits the receiver's ability to receive strong signals

18. - E4D07

Which describes the most significant effect of an off-frequency signal when it is causing cross-modulation interference to a desired signal?

Select	Answer
A	The off-frequency unwanted signal is heard in addition to the desired signal
B	A reduction in apparent signal strength
C	The desired signal can no longer be heard
D	A large increase in background noise

19. - E4E13

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

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

20. - E5A06

What is the magnitude of the circulating current within the components of a parallel LC circuit at resonance?

Select	Answer
A	It equals 2 multiplied by Pi, multiplied by frequency, multiplied by inductance
B	It is at a maximum
C	It is at a minimum
D	It equals 1 divided by the quantity 2 times Pi, multiplied by the square root of inductance L multiplied by capacitance C

21. - E5B09

What is the relationship between the current through a capacitor and the voltage across a capacitor?

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

22. - E5C09

When using rectangular coordinates to graph the impedance of a circuit, what does the horizontal axis represent?

Select	Answer
A	The difference between the resistive and reactive components
B	The sum of the reactive and resistive components
C	Reactive component
D	Resistive component

23. - E5D03

What is microstrip?

Select	Answer
A	Miniature coax used for low power applications
B	Short lengths of coax mounted on printed circuit boards to minimize time delay between microwave circuits
C	Lightweight transmission line made of common zip cord
D	Precision printed circuit conductors above a ground plane that provide constant impedance interconnects at microwave frequencies

24. - E6A17

What are the names of the three terminals of a field-effect transistor?

Select	Answer
A	Emitter, base 1, base 2
B	Gate, drain, source
C	Emitter, base, collector
D	Gate 1, gate 2, drain

25. - E6B11

What is used to control the attenuation of RF signals by a PIN diode?

Select	Answer
A	Reverse voltage larger than the RF signal
B	Capacitance of an RF coupling capacitor
C	A sub-harmonic pump signal
D	Forward DC bias current

26. - E6C02

What happens when the level of a comparator's input signal crosses the threshold?

Select	Answer
A	The feedback loop becomes unstable
B	The comparator changes its output state
C	The comparator enters latch-up
D	The IC input can be damaged

27. - E6D15

What is current in the primary winding of a transformer called if no load is attached to the secondary?

Select	Answer
A	Excitation current
B	Stabilizing current
C	Direct current
D	Magnetizing current

28. - E6E04

Which is the most common input and output impedance of circuits that use MMICs?

Select	Answer
A	10 ohms
B	300 ohms
C	50 ohms
D	450 ohms

29. - E6F07

What is a solid state relay?

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

30. - E7A01

Which is a bi-stable circuit?

Select	Answer
A	A clock
B	An "AND" gate
C	An "OR" gate
D	A flip-flop

31. - E7B01

For what portion of a signal cycle does a Class AB amplifier operate?

Select	Answer
A	Less than 180 degrees
B	Exactly 180 degrees
C	The entire cycle
D	More than 180 degrees but less than 360 degrees

32. - E7C11

Which of the following is the common name for a filter network which is equivalent to two L-networks connected back-to-back with the two inductors in series and the capacitors in shunt at the input and output?

Select	Answer
A	Pi
B	Omega
C	Cascode
D	Pi-L

33. - E7D02

What is one characteristic of a switching electronic voltage regulator?

Select	Answer
A	The resistance of a control element is varied in direct proportion to the line voltage or load current
B	It gives a ramp voltage at its output
C	The controlled device's duty cycle is changed to produce a constant average output voltage
D	It is generally less efficient than a linear regulator

34. - E7E06

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

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

35. - E7F05

How frequently must an analog signal be sampled by an analog-to-digital converter so that the signal can be accurately reproduced?

Select	Answer
A	At the same rate as the highest frequency component of the signal
B	At four times the rate of the highest frequency component of the signal
C	At twice the rate of the highest frequency component of the signal
D	At half the rate of the highest frequency component of the signal

36. - E7G08

How does the gain of an ideal operational amplifier vary with frequency?

Select	Answer
A	It decreases linearly with increasing frequency
B	It does not vary with frequency
C	It decreases logarithmically with increasing frequency
D	It increases linearly with increasing frequency

37. - E7H14

What is a phase-locked loop circuit?

Select	Answer
A	An electronic circuit consisting of a precision push-pull amplifier with a differential input
B	An electronic circuit also known as a monostable multivibrator
C	An electronic servo loop consisting of a ratio detector, reactance modulator, and voltage-controlled oscillator
D	An electronic servo loop consisting of a phase detector, a low-pass filter, a voltage-controlled oscillator, and a stable reference oscillator

38. - E8A01

What is the name of the process that shows that a square wave is made up of a sine wave plus all of its odd harmonics?

Select	Answer
A	Numerical analysis
B	Vector analysis
C	Fourier analysis
D	Differential analysis

39. - E8B02

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

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

40. - E8C05

What is the necessary bandwidth of a 13-WPM international Morse code transmission?

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

41. - E8D06

Which of the following indicates likely overmodulation of an AFSK signal such as PSK or MFSK?

Select	Answer
A	Strong ALC action
B	Harmonics on higher bands
C	High reflected power
D	Rapid signal fading

42. - E9A05

What is included in the total resistance of an antenna system?

Select	Answer
A	Radiation resistance plus transmission resistance
B	Radiation resistance plus ohmic resistance
C	Radiation resistance plus space impedance
D	Transmission-line resistance plus radiation resistance

43. - E9B13

What does the abbreviation NEC stand for when applied to antenna modeling programs?

Select	Answer
A	Next Element Comparison
B	National Electrical Code
C	Numeric Electrical Computation
D	Numerical Electromagnetic Code

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

45. - E9D04

Why should an HF mobile antenna loading coil have a high ratio of reactance to resistance?

Select	Answer
A	To minimize losses
B	To minimize the Q
C	To maximize losses
D	To swamp out harmonics

46. - E9E08

Which of the following measurements is characteristic of a mismatched transmission line?

Select	Answer
A	A reflection coefficient greater than 1
B	A dielectric constant greater than 1
C	An SWR less than 1:1
D	An SWR greater than 1:1

47. - E9F16

Which of the following is a significant difference between foam dielectric coaxial cable and solid dielectric cable, assuming all other parameters are the same?

Select	Answer
A	Foam dielectric has lower safe operating voltage limits
B	Foam dielectric has lower loss per unit of length
C	Foam dielectric has higher velocity factor
D	All of these choices are correct

48. - E9G09

What third family of circles is often added to a Smith chart during the process of solving problems?

Select	Answer
A	Radiation-pattern circles
B	Coaxial-length circles
C	Antenna-length circles
D	Standing wave ratio circles

49. - E9H07

Why is it advisable to use an RF attenuator on a receiver being used for direction finding?

Select	Answer
A	It reduces loss of received signals caused by antenna pattern nulls, thereby increasing sensitivity
B	It prevents receiver overload which could make it difficult to determine peaks or nulls
C	It narrows the bandwidth of the received signal to improve signal to noise ratio
D	It compensates for the effects of an isotropic antenna, thereby improving directivity

50. - E0A08

What does SAR measure?

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