US Amateur Radio - Amateur Extra (Element 4, 2020-2024) Practice Test

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1. - 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

2. - E1A01

Which of the following carrier frequencies is illegal for LSB AFSK emissions on the 17 meter band RTTY and data segment of 18.068 to 18.110 MHz?

Select	Answer
A	18.068 MHz
B	18.100 MHz
C	18.107 MHz
D	18.110 MHz

3. - E1B03

Within what distance must an amateur station protect an FCC monitoring facility from harmful interference?

Select	Answer
A	30 miles
B	10 miles
C	3 miles
D	1 mile

4. - E1C02

Which of the following types of communications may be transmitted to amateur stations in foreign countries?

Select	Answer
A	Messages intended for users of the maritime satellite service
B	Communications incidental to the purpose of the amateur service and remarks of a personal nature
C	All these choices are correct
D	Business-related messages for non-profit organizations

5. - E1D03

What is a space telecommand station?

Select	Answer
A	An amateur station that receives telemetry from a satellite or balloon more than 50 kilometers above the surface of the Earth
B	An amateur station located in a satellite or a balloon more than 50 kilometers above the surface of the Earth
C	An amateur station that transmits communications to initiate, modify or terminate functions of a space station
D	An amateur station located on the surface of the Earth for communication with other Earth stations by means of Earth satellites

6. - E1E12

What must the VE team do with the application form if the examinee does not pass the exam?

Select	Answer
A	Maintain the application form with the VEC's records
B	Destroy the application form
C	Return the application document to the examinee
D	Send the application form to the FCC and inform the FCC of the grade

7. - E1F04

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

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

8. - E2A03

How is the signal inverted by an inverting linear transponder?

Select	Answer
A	The signal is passed through a non-linear filter
B	The signal is passed through a mixer and the difference rather than the sum is transmitted
C	The signal is detected and remodulated on the reverse sideband
D	The signal is reduced to I and Q components and the Q component is filtered out

9. - E2B10

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

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

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 only the last two letters of your call sign until you make contact
B	Send your full call sign once or twice
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. - E2D06

Which of the following describes a method of establishing EME contacts?

Select	Answer
A	Judging optimum transmission times by monitoring beacons reflected from the moon
B	High-speed CW identification to avoid fading
C	Time synchronous transmissions alternately from each station
D	Storing and forwarding digital messages

12. - E2E10

Which of these digital modes has the narrowest bandwidth?

Select	Answer
A	300-baud packet
B	MFSK16
C	170 Hz shift, 45-baud RTTY
D	PSK31

13. - E3A07

Atmospheric ducts capable of propagating microwave signals often form over what geographic feature?

Select	Answer
A	Urban areas
B	Mountain ranges
C	Bodies of water
D	Forests

14. - E3B12

What is the primary characteristic of chordal hop propagation?

Select	Answer
A	Successive ionospheric refractions without an intermediate reflection from the ground
B	Propagation away from the great circle bearing between stations
C	Propagation across the geomagnetic equator
D	Signals reflected back toward the transmitting station

15. - E3C13

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

Select	Answer
A	Horizontal
B	Vertical
C	Circular
D	Elliptical

16. - E4A08

Which of the following measures SWR?

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

17. - E4B09

What is indicated if the current reading on an RF ammeter placed in series with the antenna feed line of a transmitter increases as the transmitter is tuned to resonance?

Select	Answer
A	There is an impedance mismatch between the antenna and feed line
B	The transmitter is not properly neutralized
C	There is more power going into the antenna
D	There is possibly a short to ground in the feed line

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

19. - E4D12

What is the term for the reduction in receiver sensitivity caused by a strong signal near the received frequency?

Select	Answer
A	Cross-modulation interference
B	Quieting
C	Squelch gain rollback
D	Desensitization

20. - E4E05

How can radio frequency interference from an AC motor be suppressed?

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

21. - E5A11

What is the half-power bandwidth of a resonant circuit that has a resonant frequency of 7.1 MHz and a Q of 150?

Select	Answer
A	47.3 kHz
B	157.8 Hz
C	23.67 kHz
D	315.6 Hz

22. - E5B06

What is susceptance?

Select	Answer
A	The magnetic impedance of a circuit
B	A measure of the efficiency of a transformer
C	The ratio of magnetic field to electric field
D	The imaginary part of admittance

23. - E5C01

Which of the following represents capacitive reactance in rectangular notation?

Select	Answer
A	Omega
B	-jX
C	+jX
D	Delta

24. - E5D14

What is reactive power?

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

25. - E6A04

What is the name given to an impurity atom that adds holes to a semiconductor crystal structure?

Select	Answer
A	N-type impurity
B	Insulator impurity
C	Donor impurity
D	Acceptor impurity

26. - E6B02

What is an important characteristic of a Schottky diode as compared to an ordinary silicon diode when used as a power supply rectifier?

Select	Answer
A	Much higher reverse voltage breakdown
B	Longer carrier retention time
C	More constant reverse avalanche voltage
D	Less forward voltage drop

27. - E6C11

In Figure E6-3, what is the schematic symbol for the NOT operation (inverter)?

Select	Answer
A	5
B	6
C	4
D	2

28. - E6D07

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

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

29. - E6E05

Which of the following noise figure values is typical of a low-noise UHF preamplifier?

Select	Answer
A	2 dB
B	44 dBm
C	-20 dBm
D	-10 dB

30. - E6F08

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

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

31. - 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 only produces logic 0 at its output when all inputs are logic 1
C	It produces logic 0 at its output if all inputs are logic 1
D	It produces logic 1 at its output if all inputs are logic 0

32. - E7B07

Which of the following is a likely result when a Class C amplifier is used to amplify a single-sideband phone signal?

Select	Answer
A	Signal distortion and excessive bandwidth
B	Signal inversion
C	Increased overall intelligibility
D	Reduced intermodulation products

33. - E7C07

Which describes a Pi-L-network used for matching a vacuum tube final amplifier to a 50-ohm unbalanced output?

Select	Answer
A	A Pi-network with an additional series inductor on the output
B	A network with only three discrete parts
C	A Phase Inverter Load network
D	A matching network in which all components are isolated from ground

34. - E7D11

What is the function of the pass transistor in a linear voltage regulator circuit?

Select	Answer
A	Maintains nearly constant output voltage over a wide range of load current
B	Provides a stable input impedance over a wide range of source voltage
C	Maintains nearly constant output impedance over a wide range of load current
D	Permits a wide range of output voltage settings

35. - E7E10

How does a diode envelope detector function?

Select	Answer
A	By breakdown of the Zener voltage
B	By sensing the change of reactance in the diode with respect to frequency
C	By rectification and filtering of RF signals
D	By mixing signals with noise in the transition region of the diode

36. - E7F10

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

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

37. - E7G05

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

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

38. - E7H03

How is positive feedback supplied in a Hartley oscillator?

Select	Answer
A	Through a capacitive divider
B	Through a neutralizing capacitor
C	Through link coupling
D	Through a tapped coil

39. - E8A06

What is the approximate ratio of PEP-to-average power in a typical single-sideband phone signal?

Select	Answer
A	1 to 1
B	2.5 to 1
C	25 to 1
D	100 to 1

40. - E8B07

Orthogonal Frequency Division Multiplexing is a technique used for which type of amateur communication?

Select	Answer
A	Extremely low-power contacts
B	OFDM signals are not allowed on amateur bands
C	EME
D	High-speed digital modes

41. - E8C11

What is the relationship between symbol rate and baud?

Select	Answer
A	They are the same
B	Symbol rate is only used for packet-based modes
C	Baud is only used for RTTY
D	Baud is twice the symbol rate

42. - E8D11

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

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

43. - E9A01

What is an isotropic antenna?

Select	Answer
A	A spacecraft antenna used to direct signals toward Earth
B	A horizontally polarized antenna used to compare Yagi antennas
C	A grounded antenna used to measure Earth conductivity
D	A theoretical, omnidirectional antenna used as a reference for antenna gain

44. - E9B11

What is a disadvantage of decreasing the number of wire segments in an antenna model below 10 segments per half-wavelength?

Select	Answer
A	The antenna will become mechanically unstable
B	The computed feed point impedance may be incorrect
C	The resulting design will favor radiation of harmonic energy
D	Ground conductivity will not be accurately modeled

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	Cardioid
B	A figure-8 oriented along the axis of the array
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	Improved radiation efficiency
C	Lower Q
D	Higher losses

47. - E9E06

Which of these feed line impedances would be suitable for constructing a quarter-wave Q-section for matching a 100-ohm loop to 50-ohm feed line?

Select	Answer
A	450 ohms
B	75 ohms
C	50 ohms
D	62 ohms

48. - E9F11

What impedance does a 1/8-wavelength transmission line present to a generator when the line is open at the far end?

Select	Answer
A	A capacitive reactance
B	An inductive reactance
C	Infinite
D	The same as the characteristic impedance of the line

49. - E9G10

What do the arcs on a Smith chart represent?

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

50. - E9H09

What is a Pennant antenna?

Select	Answer
A	A form of rhombic antenna terminated in a variable capacitor to provide frequency diversity
B	A stealth antenna built to look like a flagpole
C	A small, vertically oriented receiving antenna consisting of a triangular loop terminated in approximately 900 ohms
D	A four-element, high-gain vertical array invented by George Pennant

Figure E6-3