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

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1. - E0A08

What does SAR measure?

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

2. - E1A10

If an amateur station is installed aboard a ship or aircraft, what condition must be met before the station is operated?

Select	Answer
A	The amateur station must have a power supply that is completely independent of the main ship or aircraft power supply
B	The amateur station operator must agree not to transmit when the main radio of the ship or aircraft is in use
C	The amateur operator must have an FCC Marine or Aircraft endorsement on his or her amateur license
D	Its operation must be approved by the master of the ship or the pilot in command of the aircraft

3. - E1B03

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

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

4. - E1C14

How long must an operator wait after filing a notification with the Utilities Technology Council (UTC) before operating on the 2200 meter or 630 meter band?

Select	Answer
A	Operators may operate after 30 days, providing they have not been told that their station is within 1 km of PLC systems using those frequencies
B	Operators must not operate until approval is received
C	Operations may commence immediately, and may continue unless interference is reported by the UTC
D	Operators may not operate until a test signal has been transmitted in coordination with the local power company

5. - E1D04

Which of the following is required in the identification transmissions from a balloon-borne telemetry station?

Select	Answer
A	The output power of the balloon transmitter
B	Call sign
C	All these choices are correct
D	The station's six-character Maidenhead grid locator

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 80%
D	Minimum passing score of 77%

7. - E1F07

When may an amateur station send a message to a business?

Select	Answer
A	When neither the amateur nor his or her employer has a pecuniary interest in the communications
B	When the control operator is employed by the FCC or another government agency
C	When transmitting international third-party communications
D	When the total money involved does not exceed $25

8. - E2A12

What is the purpose of digital store-and-forward functions on an amateur radio satellite?

Select	Answer
A	To relay messages between satellites
B	To upload operational software for the transponder
C	To store digital messages in the satellite for later download by other stations
D	To delay download of telemetry between satellites

9. - E2B04

How is color information sent in analog SSTV?

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

10. - 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 run a net to allow many stations to contact a rare DX station
C	To relay calls to and from a DX station
D	To allocate frequencies for DXpeditions

11. - E2D07

What digital protocol is used by APRS?

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

12. - E2E03

How is the timing of FT4 contacts organized?

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

13. - E3A09

Which of the following frequency ranges is most suited for meteor scatter communications?

Select	Answer
A	220 MHz - 450 MHz
B	1.8 MHz - 1.9 MHz
C	10 MHz - 14 MHz
D	28 MHz - 148 MHz

14. - E3B06

Which of the following amateur bands most frequently provides long-path propagation?

Select	Answer
A	20 meters
B	10 meters
C	6 meters
D	80 meters

15. - E3C01

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

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

16. - E4A05

What is the purpose of the prescaler function on a frequency counter?

Select	Answer
A	It multiplies a higher frequency signal so a low-frequency counter can display the operating frequency
B	It divides a higher frequency signal so a low-frequency counter can display the input frequency
C	It prevents oscillation in a low-frequency counter circuit
D	It amplifies low-level signals for more accurate counting

17. - E4B07

What do the subscripts of S parameters represent?

Select	Answer
A	Relative quality of the data
B	Frequency order of the measurements
C	The relative time between measurements
D	The port or ports at which measurements are made

18. - E4C08

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

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

19. - E4D06

What is the term for spurious signals generated by the combination of two or more signals in a non-linear device or circuit?

Select	Answer
A	Neutralization
B	Amplifier desensitization
C	Adjacent channel interference
D	Intermodulation

20. - E4E01

What problem can occur when using an automatic notch filter (ANF) to remove interfering carriers while receiving CW signals?

Select	Answer
A	Removal of the CW signal as well as the interfering carrier
B	Received CW signals will appear to be modulated at the DSP clock frequency
C	Ringing in the DSP filter will completely remove the spaces between the CW characters
D	Any nearby signal passing through the DSP system will overwhelm the desired signal

21. - E5A01

What can cause the voltage across reactances in a series RLC circuit to be higher than the voltage applied to the entire circuit?

Select	Answer
A	Capacitance
B	Resonance
C	Resistance
D	Conductance

22. - E5B02

What letter is commonly used to represent susceptance?

Select	Answer
A	G
B	B
C	X
D	Y

23. - E5C10

Which point on Figure E5-1 best represents the impedance of a series circuit consisting of a 400-ohm resistor and a 38-picofarad capacitor at 14 MHz?

Select	Answer
A	Point 5
B	Point 4
C	Point 6
D	Point 2

24. - E5D15

What is the power factor of an RL circuit having a 45-degree phase angle between the voltage and the current?

Select	Answer
A	0.707
B	1.0
C	0.5
D	0.866

25. - E6A06

What is the beta of a bipolar junction transistor?

Select	Answer
A	The breakdown voltage of the base to collector junction
B	The frequency at which the current gain is reduced to 0.707
C	The change in collector current with respect to base current
D	The switching speed

26. - E6B09

What is a common use for point-contact diodes?

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

27. - E6C03

What is tri-state logic?

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

28. - E6D08

What is one reason for using powdered-iron cores rather than ferrite cores in an inductor?

Select	Answer
A	Powdered-iron cores use smaller diameter wire for the same inductance
B	Powdered-iron cores generally have greater initial permeability
C	Powdered-iron cores generally require fewer turns to produce a given inductance
D	Powdered-iron cores generally maintain their characteristics at higher currents

29. - E6E03

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

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

30. - E6F06

Which of these materials is most commonly used to create photoconductive devices?

Select	Answer
A	A liquid semiconductor
B	A crystalline semiconductor
C	An ordinary metal
D	A heavy metal

31. - E7A04

How many flip-flops are required to divide a signal frequency by 4?

Select	Answer
A	4
B	8
C	2
D	1

32. - E7B15

What is one way to prevent thermal runaway in a bipolar transistor amplifier?

Select	Answer
A	All these choices are correct
B	Neutralization
C	Use a resistor in series with the emitter
D	Select transistors with high beta

33. - E7C09

What is a crystal lattice filter?

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

34. - E7D11

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

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

35. - E7E09

What occurs when an excessive amount of signal energy reaches a mixer circuit?

Select	Answer
A	Automatic limiting occurs
B	A beat frequency is generated
C	Mixer blanking occurs
D	Spurious mixer products are generated

36. - E7F09

Why is an anti-aliasing digital filter required in a digital decimator?

Select	Answer
A	It peaks the response of the decimator, improving bandwidth
B	It notches out the sampling frequency to avoid sampling errors
C	It removes high-frequency signal components that would otherwise be reproduced as lower frequency components
D	It removes low-frequency signal components to eliminate the need for DC restoration

37. - E7G06

What is the gain-bandwidth of an operational amplifier?

Select	Answer
A	The frequency at which the amplifier's offset voltage is zero
B	The gain of the amplifier at a filter's cutoff frequency
C	The frequency at which the open-loop gain of the amplifier equals one
D	The maximum frequency for a filter circuit using that type of amplifier

38. - E7H04

How is positive feedback supplied in a Colpitts oscillator?

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

39. - E8A02

Which of the following is a type of analog-to-digital conversion?

Select	Answer
A	Level shifting
B	Phase reversal
C	Successive approximation
D	Harmonic regeneration

40. - E8B03

What is the modulation index of an FM-phone signal having a maximum frequency deviation of 3000 Hz either side of the carrier frequency when the modulating frequency is 1000 Hz?

Select	Answer
A	3000
B	3
C	0.3
D	1000

41. - E8C02

What is the definition of symbol rate in a digital transmission?

Select	Answer
A	The duration of each bit in a message sent over the air
B	The number of characters carried per second by the station-to-station link
C	The rate at which the waveform changes to convey information
D	The number of control characters in a message packet

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 is possible to transmit both upper and lower case text
C	It contains fewer information bits per character than any other code
D	It includes built-in error correction features

43. - E9A08

What is antenna bandwidth?

Select	Answer
A	The angle between the half-power radiation points
B	Antenna length divided by the number of elements
C	The frequency range over which an antenna satisfies a performance requirement
D	The angle formed between two imaginary lines drawn through the element ends

44. - E9B02

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

Select	Answer
A	14 dB
B	24 dB
C	36 dB
D	18 dB

45. - E9C13

How does the radiation pattern of a horizontally polarized 3-element beam antenna vary with increasing height above ground?

Select	Answer
A	The horizontal beamwidth decreases
B	The takeoff angle of the lowest elevation lobe decreases
C	The horizontal beamwidth increases
D	The takeoff angle of the lowest elevation lobe increases

46. - E9D12

Which of the following would provide the best RF ground for your station?

Select	Answer
A	A 50-ohm resistor connected to ground
B	An electrically short connection to 3 or 4 interconnected ground rods via a series RF choke
C	An electrically short connection to 3 or 4 interconnected ground rods driven into the Earth
D	An electrically short connection to a metal water pipe

47. - E9E03

What is the name of the matching system that uses a section of transmission line connected in parallel with the feed line at or near the feed point?

Select	Answer
A	The omega match
B	The delta match
C	The stub match
D	The gamma match

48. - E9F06

What is the approximate physical length of an air-insulated, parallel conductor transmission line that is electrically 1/2 wavelength long at 14.10 MHz?

Select	Answer
A	7.0 meters
B	10.6 meters
C	8.5 meters
D	13.3 meters

49. - E9G03

Which of the following is often determined using a Smith chart?

Select	Answer
A	Beam headings and radiation patterns
B	Impedance and SWR values in transmission lines
C	Trigonometric functions
D	Satellite azimuth and elevation bearings

50. - E9H05

What is the main drawback of a small wire-loop antenna for direction finding?

Select	Answer
A	It is practical for use only on VHF and higher bands
B	It has a bidirectional pattern
C	It has no clearly defined null
D	All these choices are correct

Figure E5-1

Figure E9-1