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

2. - E1A12

What special operating frequency restrictions are imposed on slow scan TV transmissions?

Select	Answer
A	They are not permitted above 54 MHz
B	None; they are allowed on all amateur frequencies
C	They are restricted to 7.245 MHz, 14.245 MHz, 21.345 MHz, and 28.945 MHz
D	They are restricted to phone band segments

3. - E1B10

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

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

4. - E1C13

What notifications must be given before transmitting on the 630 meter or 2200 meter bands?

Select	Answer
A	An environmental impact statement must be filed with the Department of the Interior
B	Operators must inform the Utilities Technology Council (UTC) of their call sign and coordinates of the station
C	Operators must inform the FAA of their intent to operate, giving their call sign and distance to the nearest runway
D	A special endorsement must be requested from the FCC

5. - E1D12

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

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

6. - E1E03

What is a Volunteer Examiner Coordinator?

Select	Answer
A	A person who has volunteered to administer amateur operator license examinations
B	The person who has entered into an agreement with the FCC to be the VE session manager
C	A person who has volunteered to prepare amateur operator license examinations
D	An organization that has entered into an agreement with the FCC to coordinate, prepare, and administer amateur operator license examinations

7. - E1F08

Which of the following types of amateur station communications are prohibited?

Select	Answer
A	Communications that have religious content
B	Communications that have political content, except as allowed by the Fairness Doctrine
C	Communications transmitted for hire or material compensation, except as otherwise provided in the rules
D	Communications in a language other than English

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 detected and remodulated on the reverse sideband
C	The signal is passed through a mixer and the difference rather than the sum is transmitted
D	The signal is reduced to I and Q components and the Q component is filtered out

9. - E2B05

Which of the following describes the use of vestigial sideband in analog fast-scan TV transmissions?

Select	Answer
A	Vestigial sideband provides high frequency emphasis to sharpen the picture
B	The vestigial sideband contains chroma information
C	The vestigial sideband carries the audio information
D	Vestigial sideband reduces bandwidth while allowing for simple video detector circuitry

10. - E2C08

Which of the following contacts may be confirmed through the U.S. QSL bureau system?

Select	Answer
A	Contacts between a U.S. station and a non-U.S. station
B	Special event contacts between stations in the U.S.
C	Repeater contacts between U.S. club members
D	Contacts using tactical call signs

11. - E2D05

What is one advantage of the JT65 mode?

Select	Answer
A	The ability to decode signals which have a very low signal-to-noise ratio
B	Permits fast-scan TV transmissions over narrow bandwidth
C	Easily copied by ear if necessary
D	Uses only a 65 Hz bandwidth

12. - E2E03

How is the timing of FT4 contacts organized?

Select	Answer
A	Alternating transmissions at 7.5 second intervals
B	By exchanging ACK/NAK packets
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	28 MHz - 148 MHz
B	10 MHz - 14 MHz
C	1.8 MHz - 1.9 MHz
D	220 MHz - 450 MHz

14. - E3B10

Why is chordal hop propagation desirable?

Select	Answer
A	The signal experiences less loss compared to multi-hop using Earth as a reflector
B	Signals travel faster along ionospheric chords
C	The MUF for chordal hop propagation is much lower than for normal skip propagation
D	Atmospheric noise is lower in the direction of chordal hop propagation

15. - E3C06

By how much does the VHF/UHF radio horizon distance exceed the geometric horizon?

Select	Answer
A	By approximately 15 percent of the distance
B	By approximately 50 percent of the distance
C	By approximately twice the distance
D	By approximately four times the distance

16. - E4A04

How is the compensation of an oscilloscope probe typically adjusted?

Select	Answer
A	A high frequency sine wave is displayed and the probe is adjusted for maximum amplitude
B	A frequency standard is displayed and the probe is adjusted until the deflection time is accurate
C	A DC voltage standard is displayed and the probe is adjusted until the displayed voltage is accurate
D	A square wave is displayed and the probe is adjusted until the horizontal portions of the displayed wave are as nearly flat as possible

17. - E4B08

Which of the following can be used to measure the Q of a series-tuned circuit?

Select	Answer
A	The inductance to capacitance ratio
B	The frequency shift
C	The bandwidth of the circuit's frequency response
D	The resonant frequency of the circuit

18. - E4C10

What is an advantage of having a variety of receiver IF bandwidths from which to select?

Select	Answer
A	Receiver power consumption can be reduced when wider bandwidth is not required
B	Receive bandwidth can be set to match the modulation bandwidth, maximizing signal-to-noise ratio and minimizing interference
C	Multiple frequencies can be received simultaneously if desired
D	The noise figure of the RF amplifier can be adjusted to match the modulation type, thus increasing receiver sensitivity

19. - E4D04

Which of the following may reduce or eliminate intermodulation interference in a repeater caused by another transmitter operating in close proximity?

Select	Answer
A	A band-pass filter in the feed line between the transmitter and receiver
B	A properly terminated circulator at the output of the repeater's transmitter
C	Utilizing a Class C final amplifier
D	Utilizing a Class D final amplifier

20. - E4E04

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

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

21. - E5A05

What is the result of increasing the Q of an impedance-matching circuit?

Select	Answer
A	Matching bandwidth is decreased
B	Matching range is increased
C	It has no effect on impedance matching
D	Matching bandwidth is increased

22. - E5B11

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 25 ohms, R is 100 ohms, and XL is 50 ohms?

Select	Answer
A	14 degrees with the voltage leading the current
B	76 degrees with the voltage lagging the current
C	14 degrees with the voltage lagging the current
D	76 degrees with the voltage leading the current

23. - E5C01

Which of the following represents capacitive reactance in rectangular notation?

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

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	200 watts
B	141.4 watts
C	100 watts
D	70.7 watts

25. - E6A07

Which of the following indicates that a silicon NPN junction transistor is biased on?

Select	Answer
A	Base-to-emitter voltage of approximately 6 to 7 volts
B	Base-to-emitter resistance of approximately 0.6 to 0.7 ohms
C	Base-to-emitter resistance of approximately 6 to 7 ohms
D	Base-to-emitter voltage of approximately 0.6 to 0.7 volts

26. - E6B05

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

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

27. - E6C11

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

Select	Answer
A	5
B	4
C	2
D	6

28. - E6D13

What is the primary cause of inductor self-resonance?

Select	Answer
A	Non-linear core hysteresis
B	Inductive kickback
C	Inter-turn capacitance
D	The skin effect

29. - E6E03

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

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

30. - E6F05

Which describes an optical shaft encoder?

Select	Answer
A	A device that detects rotation of a control by interrupting a light source with a patterned wheel
B	A device that measures the strength of a beam of light using analog to digital conversion
C	A device for generating RTTY signals by means of a rotating light source
D	A digital encryption device often used to encrypt spacecraft control signals

31. - E7A04

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

Select	Answer
A	8
B	4
C	1
D	2

32. - E7B08

How can an RF power amplifier be neutralized?

Select	Answer
A	By increasing the driving power
B	By feeding a 180-degree out-of-phase portion of the output back to the input
C	By feeding an in-phase component of the output back to the input
D	By reducing the driving power

33. - E7C12

What is one advantage of a Pi-matching network over an L-matching network consisting of a single inductor and a single capacitor?

Select	Answer
A	Pi-networks provide balanced input and output
B	Pi-networks are more stable
C	L-networks cannot perform impedance transformation
D	The Q of Pi-networks can be controlled

34. - E7D10

What is the primary reason that a high-frequency switching type high-voltage power supply can be both less expensive and lighter in weight than a conventional power supply?

Select	Answer
A	The high frequency inverter design uses much smaller transformers and filter components for an equivalent power output
B	It uses a large power factor compensation capacitor to recover power from the unused portion of the AC cycle
C	It uses a diode bridge rectifier for increased output
D	The inverter design does not require any output filtering

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 mixing signals with noise in the transition region of the diode
D	By rectification and filtering of RF signals

36. - 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 least half the rate of the highest frequency component of the signal
B	At the same rate as the highest frequency component of the signal
C	At four times the rate of the highest frequency component of the signal
D	At least twice the rate of the highest frequency component of the signal

37. - E7G12

What is an operational amplifier?

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

38. - E7H05

How is positive feedback supplied in a Pierce oscillator?

Select	Answer
A	Through a neutralizing capacitor
B	Through link coupling
C	Through a quartz crystal
D	Through a tapped coil

39. - E8A09

How many different input levels can be encoded by an analog-to-digital converter with 8-bit resolution?

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

40. - E8B01

What is the modulation index of an FM signal?

Select	Answer
A	The ratio of modulating signal amplitude to frequency deviation
B	The type of modulation used by the transmitter
C	The ratio of frequency deviation to modulating signal frequency
D	The bandwidth of the transmitted signal divided by the modulating signal frequency

41. - E8C05

What is the approximate bandwidth of a 13-WPM International Morse Code transmission?

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

42. - E8D07

What is a common cause of overmodulation of AFSK signals?

Select	Answer
A	Excessive transmit audio levels
B	Excessive numbers of retries
C	Ground loops
D	Bit errors in the modem

43. - E9A07

What is the effective isotropic 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

44. - E9B08

What is the far field of an antenna?

Select	Answer
A	The region where radiated field strengths are constant
B	The region where the shape of the antenna pattern is independent of distance
C	The region of the ionosphere where radiated power is not refracted
D	The region where radiated power dissipates over a specified time period

45. - E9C08

What is a folded dipole antenna?

Select	Answer
A	A half-wave dipole with an additional parallel wire connecting its two ends
B	A dipole one-quarter wavelength long
C	A dipole configured to provide forward gain
D	A type of ground-plane antenna

46. - E9D11

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

Select	Answer
A	Wide flat copper strap
B	Resistive wire, such as spark plug wire
C	Solid wire
D	Stranded 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	75 ohms
B	450 ohms
C	50 ohms
D	62 ohms

48. - E9F04

What impedance does a 1/2-wavelength transmission line present to a generator when the line is shorted at the far end?

Select	Answer
A	The same as the output impedance of the generator
B	The same as the characteristic impedance of the line
C	Very high impedance
D	Very low impedance

49. - E9G04

What are the two families of circles and arcs that make up a Smith chart?

Select	Answer
A	Resistance and reactance
B	Voltage and impedance
C	Resistance and voltage
D	Reactance and voltage

50. - E9H03

What is Receiving Directivity Factor (RDF)?

Select	Answer
A	Forward gain compared to average gain over the entire hemisphere
B	Forward gain compared to the gain in the reverse direction
C	Relative directivity compared to isotropic
D	Relative directivity compared to a dipole

Figure E6-3