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

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1. - E0A05

What is one of the potential hazards of operating in the amateur radio microwave bands?

Select	Answer
A	The high gain antennas commonly used can result in high exposure levels
B	Microwaves are ionizing radiation
C	Microwaves often travel long distances by ionospheric reflection
D	The extremely high frequency energy can damage the joints of antenna structures

2. - E1A13

Who must be in physical control of the station apparatus of an amateur station aboard any vessel or craft that is documented or registered in the United States?

Select	Answer
A	Any person named in an amateur station license grant or a person holding an unrestricted Radiotelephone Operator Permit
B	Only a person named in an amateur station license grant
C	Any person holding an FCC issued amateur license or who is authorized for alien reciprocal operation
D	Only a person with an FCC Marine Radio license grant

3. - E1B07

To what type of regulations does PRB-1 apply?

Select	Answer
A	FAA tower height limits
B	Homeowners associations
C	State and local zoning
D	Use of wireless devices in vehicles

4. - E1C05

When may an automatically controlled station originate third party communications?

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

5. - E1D12

Which of the following amateur stations may transmit one-way communications?

Select	Answer
A	A space station, beacon station, or telecommand station
B	All these choices are correct
C	A local repeater or linked repeater station
D	A message forwarding station or automatically controlled digital station

6. - E1E05

What is the minimum passing score on all amateur operator license examinations?

Select	Answer
A	Minimum passing score of 74%
B	Minimum passing score of 70%
C	Minimum passing score of 77%
D	Minimum passing score of 80%

7. - E1F10

Who may be the control operator of an auxiliary station?

Select	Answer
A	Only Amateur Extra Class operators
B	Any licensed amateur operator
C	Only Technician, General, Advanced or Amateur Extra Class operators
D	Only General, Advanced or Amateur Extra Class operators

8. - E2A07

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

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

9. - E2B04

How is color information sent in analog SSTV?

Select	Answer
A	Color information is sent on a 2.8 kHz subcarrier
B	Color is amplitude modulated on the frequency modulated intensity signal
C	Color lines are sent sequentially
D	Color is sent in a color burst at the end of each line

10. - E2C10

Why might a DX station state that they are listening on another frequency?

Select	Answer
A	To improve operating efficiency by reducing interference
B	To separate the calling stations from the DX station
C	All these choices are correct
D	Because the DX station may be transmitting on a frequency that is prohibited to some responding stations

11. - E2D10

How can an APRS station be used to help support a public service communications activity?

Select	Answer
A	All these choices are correct
B	APRS stations with General Personnel Scanners can automatically relay the participant numbers and time as they pass the check points
C	An APRS station with an emergency medical technician can automatically transmit medical data to the nearest hospital
D	An APRS station with a Global Positioning System unit can automatically transmit information to show a mobile station's position during the event

12. - E2E03

How is the timing of FT4 contacts organized?

Select	Answer
A	By exchanging ACK/NAK packets
B	It depends on the lunar phase
C	Stations take turns on alternate days
D	Alternating transmissions at 7.5 second intervals

13. - E3A05

Tropospheric propagation of microwave signals often occurs in association with what phenomenon?

Select	Answer
A	Grayline
B	Lightning discharges
C	Warm and cold fronts
D	Sprites and jets

14. - E3B02

What is the approximate maximum range for signals using transequatorial propagation?

Select	Answer
A	5000 miles
B	1000 miles
C	7500 miles
D	2500 miles

15. - E3C01

What does the radio communication term "ray tracing" describe?

Select	Answer
A	The process in which an electronic display presents a pattern
B	Evaluating high voltage sources for x-rays
C	Determining the radiation pattern from an array of antennas
D	Modeling a radio wave's path through the ionosphere

16. - E4A09

Which of the following is good practice when using an oscilloscope probe?

Select	Answer
A	Keep the signal ground connection of the probe as short as possible
B	Never use a high-impedance probe to measure a low-impedance circuit
C	All these choices are correct
D	Never use a DC-coupled probe to measure an AC circuit

17. - E4B11

Which of the following can be measured with a vector network analyzer?

Select	Answer
A	Input impedance
B	Reflection coefficient
C	All these choices are correct
D	Output impedance

18. - E4C08

An SDR receiver is overloaded when input signals exceed what level?

Select	Answer
A	One-half the maximum sampling buffer size
B	The reference voltage of the analog-to-digital converter
C	One-half the maximum sample rate
D	The maximum count value of the analog-to-digital converter

19. - E4D05

What transmitter frequencies would cause an intermodulation-product signal in a receiver tuned to 146.70 MHz when a nearby station transmits on 146.52 MHz?

Select	Answer
A	146.88 MHz and 146.34 MHz
B	146.10 MHz and 147.30 MHz
C	146.34 MHz and 146.61 MHz
D	173.35 MHz and 139.40 MHz

20. - E4E04

How can conducted and radiated noise caused by an automobile alternator be suppressed?

Select	Answer
A	By installing a noise suppression resistor and a blocking capacitor in both leads
B	By installing a high-pass filter in series with the radio's power lead and a low-pass filter in parallel with the field lead
C	By connecting the radio's power leads directly to the battery and by installing coaxial capacitors in line with the alternator leads
D	By installing filter capacitors in series with the DC power lead and a blocking capacitor in the field lead

21. - E5A16

What is the resonant frequency of an RLC circuit if R is 33 ohms, L is 50 microhenries and C is 10 picofarads?

Select	Answer
A	23.5 MHz
B	7.12 kHz
C	7.12 MHz
D	23.5 kHz

22. - 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	220 seconds
B	440 seconds
C	55 seconds
D	110 seconds

23. - E5C06

What does the impedance 50-j25 represent?

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

24. - E5D13

How many watts are consumed in a circuit consisting of a 100-ohm resistor in series with a 100-ohm inductive reactance drawing 1 ampere?

Select	Answer
A	141.4 watts
B	70.7 watts
C	100 watts
D	200 watts

25. - E6A01

In what application is gallium arsenide used as a semiconductor material?

Select	Answer
A	In high-current rectifier circuits
B	In high-power audio circuits
C	In very low-frequency RF circuits
D	In microwave circuits

26. - E6B05

What characteristic of a PIN diode makes it useful as an RF switch?

Select	Answer
A	Reverse bias controls its forward voltage drop
B	Extremely high reverse breakdown voltage
C	Low junction capacitance
D	Ability to dissipate large amounts of power

27. - E6C03

What is tri-state logic?

Select	Answer
A	Logic devices with 0, 1, and high-impedance output states
B	Low-power logic devices designed to operate at 3 volts
C	Proprietary logic devices manufactured by Tri-State Devices
D	Logic devices that utilize ternary math

28. - E6D12

What is inductor saturation?

Select	Answer
A	The inductor's voltage rating is exceeded causing a flashover
B	The inductor windings are over-coupled
C	Adjacent inductors become over-coupled
D	The ability of the inductor's core to store magnetic energy has been exceeded

29. - E6E09

Which of the following component package types would be most suitable for use at frequencies above the HF range?

Select	Answer
A	Radial lead
B	Axial lead
C	Surface mount
D	TO-220

30. - E6F07

What is a solid-state relay?

Select	Answer
A	A semiconductor passive delay line
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 relay using transistors to drive the relay coil

31. - E7A10

What is a truth table?

Select	Answer
A	A table of logic symbols that indicate the logic states of an op-amp
B	A table of logic symbols that indicate the high logic states of an op-amp
C	A diagram showing logic states when the digital device output is true
D	A list of inputs and corresponding outputs for a digital device

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. - E7C09

What is a crystal lattice filter?

Select	Answer
A	A filter with narrow bandwidth and steep skirts made using quartz crystals
B	An audio filter made with four quartz crystals that resonate at 1 kHz intervals
C	A filter using lattice-shaped quartz crystals for high-Q performance
D	A power supply filter made with interlaced quartz crystals

34. - E7D02

What is a 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	It is generally less efficient than a linear regulator
D	The resistance of a control element is varied in direct proportion to the line voltage or load current

35. - E7E05

What circuit is added to an FM transmitter to boost the higher audio frequencies?

Select	Answer
A	A pre-emphasis network
B	A de-emphasis network
C	A heterodyne enhancer
D	A heterodyne suppressor

36. - E7F02

What kind of digital signal processing audio filter is used to remove unwanted noise from a received SSB signal?

Select	Answer
A	A crystal-lattice filter
B	A Hilbert-transform filter
C	An adaptive filter
D	A phase-inverting filter

37. - E7G12

What is an operational amplifier?

Select	Answer
A	An amplifier used to increase the average output of frequency modulated amateur signals to the legal limit
B	A digital audio amplifier whose characteristics are determined by components external to the amplifier
C	A RF amplifier used in the UHF and microwave regions
D	A high-gain, direct-coupled differential amplifier with very high input impedance and very low output impedance

38. - E7H14

What is a phase-locked loop circuit?

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

39. - E8A01

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

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

40. - E8B11

What is digital time division multiplexing?

Select	Answer
A	Two or more signals are quadrature modulated to increase bandwidth efficiency
B	Two or more data streams share the same channel by transmitting time of transmission as the sub-carrier
C	Two or more data streams are assigned to discrete sub-carriers on an FM transmitter
D	Two or more signals are arranged to share discrete time slots of a data transmission

41. - E8C11

What is the relationship between symbol rate and baud?

Select	Answer
A	Symbol rate is only used for packet-based modes
B	They are the same
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 includes built-in error correction features
C	It is possible to transmit both upper and lower case text
D	It contains fewer information bits per character than any other code

43. - 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	Soil conductivity
C	Distance from the transmitter
D	The standing wave ratio

44. - E9B03

In the antenna radiation pattern shown in Figure E9-1, what is the front-to-side ratio?

Select	Answer
A	12 dB
B	18 dB
C	14 dB
D	24 dB

45. - E9C05

Which of the following is a type of OCFD antenna?

Select	Answer
A	A dipole fed approximately 1/3 the way from one end with a 4:1 balun to provide multiband operation
B	A folded dipole center-fed with 300-ohm transmission line
C	A remotely tunable dipole antenna using orthogonally controlled frequency diversity
D	A multiband dipole antenna using one-way circular polarization for frequency diversity

46. - E9D11

Which of the following conductors would be best for minimizing losses in a station's RF ground system?

Select	Answer
A	Stranded wire
B	Solid wire
C	Wide flat copper strap
D	Resistive wire, such as spark plug wire

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	50 ohms
B	450 ohms
C	75 ohms
D	62 ohms

48. - E9F05

What is the approximate physical length of a solid polyethylene dielectric coaxial transmission line that is electrically 1/4 wavelength long at 14.1 MHz?

Select	Answer
A	10.6 meters
B	3.5 meters
C	5.3 meters
D	4.3 meters

49. - E9G02

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

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

50. - E9H10

How can the output voltage of a multiple-turn receiving loop antenna be increased?

Select	Answer
A	By reducing the permeability of the loop shield
B	By utilizing high impedance wire for the coupling loop
C	By increasing the number of turns and/or the area
D	By winding adjacent turns in opposing directions

Figure E9-1