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

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1. - E1A06

Where must the carrier frequency of a CW signal be set to comply with FCC rules for 60 meter operation?

Select	Answer
A	At the center frequency of the channel
B	At the lowest frequency of the channel
C	At the highest frequency of the channel
D	On any frequency where the signal's sidebands are within the channel

2. - E1B11

What is the permitted mean power of any spurious emission relative to the mean power of the fundamental emission from a station transmitter or external RF amplifier installed after January 1, 2003 and transmitting on a frequency below 30 MHZ?

Select	Answer
A	At least 73 dB below
B	At least 43 dB below
C	At least 63 dB below
D	At least 53 dB below

3. - E1C05

When may an automatically controlled station originate third party communications?

Select	Answer
A	Never
B	Only when transmitting RTTY or data emissions
C	When agreed upon by the sending or receiving station
D	When approved by the National Telecommunication and Information Administration

4. - E1D10

Which amateur stations are eligible to be telecommand stations?

Select	Answer
A	All of these choices are correct
B	Any amateur station so designated by the space station licensee, subject to the privileges of the class of operator license held by the control operator
C	Any amateur station designated by NASA
D	Any amateur station so designated by the ITU

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	Record the exam session on video tape for later review by the VE team
C	The exam proctor observes the applicants and reports any violations
D	Have each applicant sign an affidavit stating that all session rules were followed

6. - E1F01

On what frequencies are spread spectrum transmissions permitted?

Select	Answer
A	Only on amateur frequencies above 420 MHz
B	Only on amateur frequencies above 222 MHz
C	Only on amateur frequencies above 144 MHz
D	Only on amateur frequencies above 50 MHz

7. - E2A11

What type of antenna can be used to minimize the effects of spin modulation and Faraday rotation?

Select	Answer
A	A linearly polarized antenna
B	An isotropic antenna
C	A log-periodic dipole array
D	A circularly polarized antenna

8. - E2B14

What aspect of an amateur slow-scan television signal encodes the brightness of the picture?

Select	Answer
A	Tone frequency
B	Tone amplitude
C	Sync frequency
D	Sync amplitude

9. - E2C05

What is the function of a DX QSL Manager?

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

10. - E2D03

Which of the following digital modes is especially useful for EME communications?

Select	Answer
A	Olivia
B	JT65
C	PACTOR III
D	FSK441

11. - E2E13

Which of the following is a possible reason that attempts to initiate contact with a digital station on a clear frequency are unsuccessful?

Select	Answer
A	Your transmit frequency is incorrect
B	The protocol version you are using is not the supported by the digital station
C	All of these choices are correct
D	Another station you are unable to hear is using the frequency

12. - E3A06

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

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

13. - E3B14

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	Their polarization is randomly modified
D	They become phase-locked

14. - E3C13

What type of polarization is best for ground-wave propagation?

Select	Answer
A	Horizontal
B	Circular
C	Elliptical
D	Vertical

15. - E4A06

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

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

16. - E4B12

What is the significance of voltmeter sensitivity expressed in ohms per volt?

Select	Answer
A	The full scale reading of the voltmeter multiplied by its ohms per volt rating will indicate the input impedance of the voltmeter
B	When used as an ammeter, the full scale reading in amps divided by ohms per volt rating will determine the size of shunt needed
C	When used as a galvanometer, the reading in volts multiplied by the ohms per volt rating will determine the power drawn by the device under test
D	When used as an ohmmeter, the reading in ohms divided by the ohms per volt rating will determine the voltage applied to the circuit

17. - E4C02

Which of the following portions of a receiver can be effective in eliminating image signal interference?

Select	Answer
A	A notch filter
B	A narrow IF filter
C	A properly adjusted product detector
D	A front-end filter or pre-selector

18. - E4D01

What is meant by the blocking dynamic range of a receiver?

Select	Answer
A	The difference in dB between the noise floor and the level of an incoming signal which will cause 1 dB of gain compression
B	The minimum difference in dB between the levels of two FM signals which will cause one signal to block the other
C	The minimum difference in dB between two signals which produce third order intermodulation products greater than the noise floor
D	The difference in dB between the noise floor and the third order intercept point

19. - E4E03

Which of the following signals might a receiver noise blanker be able to remove from desired signals?

Select	Answer
A	Signals which are constant at all IF levels
B	Signals which have a sharply peaked frequency distribution
C	Signals which appear at one IF but not another
D	Signals which appear across a wide bandwidth

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

21. - E5B04

What is the time constant of a circuit having two 220 microfarad capacitors and two 1 megohm resistors, all in parallel?

Select	Answer
A	110 seconds
B	220 seconds
C	440 seconds
D	55 seconds

22. - E5C06

What does the impedance 50-j25 represent?

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

23. - E5D18

How many watts are consumed in a circuit having a power factor of 0.71 if the apparent power is 500VA?

Select	Answer
A	252 W
B	355 W
C	704 W
D	1.42 mW

24. - E6A11

In Figure E6-2, what is the schematic symbol for a P-channel junction FET?

Select	Answer
A	6
B	1
C	3
D	2

25. - E6B12

What is one common use for PIN diodes?

Select	Answer
A	As an RF switch
B	As a constant current source
C	As a high voltage rectifier
D	As a constant voltage source

26. - E6C01

What is the function of hysteresis in a comparator?

Select	Answer
A	To prevent input noise from causing unstable output signals
B	To allow the comparator to be used with AC input signal
C	To increase the sensitivity
D	To cause the output to change states continually

27. - E6D16

What is the common name for a capacitor connected across a transformer secondary that is used to absorb transient voltage spikes?

Select	Answer
A	Trimmer capacitor
B	Feedback capacitor
C	Clipper capacitor
D	Snubber capacitor

28. - E6E03

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

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

29. - E6F08

Why are optoisolators often used in conjunction with solid state circuits when switching 120VAC?

Select	Answer
A	Optoisolators provide a low impedance link between a control circuit and a power circuit
B	Optoisolators provide impedance matching between the control circuit and power circuit
C	Optoisolators provide a very high degree of electrical isolation between a control circuit and the circuit being switched
D	Optoisolators eliminate the effects of reflected light in the control circuit

30. - E7A05

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

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

31. - E7B04

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

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

32. - E7C03

What advantage does a Pi-L-network have over a regular Pi-network for impedance matching between the final amplifier of a vacuum-tube transmitter and an antenna?

Select	Answer
A	Greater harmonic suppression
B	Higher efficiency
C	Lower losses
D	Greater transformation range

33. - E7D02

What is one characteristic of a switching electronic voltage regulator?

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

34. - E7E02

What is the function of a reactance modulator?

Select	Answer
A	To produce AM signals by using an electrically variable resistance
B	To produce PM signals by using an electrically variable inductance or capacitance
C	To produce PM signals by using an electrically variable resistance
D	To produce AM signals by using an electrically variable inductance or capacitance

35. - E7F10

What aspect of receiver analog-to-digital conversion determines the maximum receive bandwidth of a Direct Digital Conversion SDR?

Select	Answer
A	Sample rate
B	Sample clock phase noise
C	Sample width in bits
D	Processor latency

36. - E7G03

What is the typical input impedance of an integrated circuit op-amp?

Select	Answer
A	Very high
B	1000 ohms
C	100 ohms
D	Very low

37. - E7H12

Which of the following must be done to insure that a crystal oscillator provides the frequency specified by the crystal manufacturer?

Select	Answer
A	Provide the crystal with a specified parallel capacitance
B	Provide the crystal with a specified parallel inductance
C	Bias the crystal at a specified current
D	Bias the crystal at a specified voltage

38. - E8A09

How many levels can an analog-to-digital converter with 8 bit resolution encode?

Select	Answer
A	256
B	256 divided by the gain of the input amplifier
C	8 multiplied by the gain of the input amplifier
D	8

39. - E8B02

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

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

40. - E8C05

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

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

41. - E8D11

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

Select	Answer
A	It includes built in error correction features
B	It is possible to transmit both upper and lower case text
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

42. - E9A17

What is the effective 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	159 watts
B	63.2 watts
C	252 watts
D	632 watts

43. - E9B13

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

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

44. - E9C10

Which of the following describes a Zepp antenna?

Select	Answer
A	An end fed dipole antenna
B	An omni-directional antenna commonly used for satellite communications
C	A dipole constructed from zip cord
D	A vertical array capable of quickly changing the direction of maximum radiation by changing phasing lines

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 collinear to each other with the driven elements fed 180 degrees out of phase
C	Arrange two Yagis perpendicular to each other with the driven elements at the same point on the boom fed 90 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	A series capacitor
B	Pi-network
C	A shunt inductor
D	Pi-L-network

47. - E9F04

What is the typical velocity factor for a coaxial cable with solid polyethylene dielectric?

Select	Answer
A	0.66
B	0.10
C	0.30
D	2.70

48. - E9G10

What do the arcs on a Smith chart represent?

Select	Answer
A	Points with constant reactance
B	Points with constant resistance
C	Frequency
D	SWR

49. - E9H04

What is an advantage of using a shielded loop antenna for direction finding?

Select	Answer
A	It automatically cancels ignition noise in mobile installations
B	It allows stations to communicate without giving away their position
C	It is electro statically balanced against ground, giving better nulls
D	It eliminates tracking errors caused by strong out-of-band signals

50. - E0A08

What does SAR measure?

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

Figure E6-2