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

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1. - E0A10

What toxic material may be present in some electronic components such as high voltage capacitors and transformers?

Select	Answer
A	Polychlorinated biphenyls
B	Polymorphic silicon
C	Polytetrafluoroethylene
D	Polyethylene

2. - E1A02

When using a transceiver that displays the carrier frequency of phone signals, which of the following displayed frequencies represents the lowest frequency at which a properly adjusted LSB emission will be totally within the band?

Select	Answer
A	The exact lower band edge
B	3 kHz above the lower band edge
C	300 Hz above the lower band edge
D	1 kHz above the lower band edge

3. - E1B10

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

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

4. - E1C01

What is the maximum bandwidth for a data emission on 60 meters?

Select	Answer
A	2.8 kHz
B	1.5 kHz
C	60 Hz
D	170 Hz

5. - E1D04

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

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

6. - E1E05

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

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

7. - E1F08

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

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

8. - E2A04

What is meant by the term mode? as applied to an amateur radio satellite?

Select	Answer
A	The satellite's orientation with respect to the Earth
B	Whether the satellite is in a low earth or geostationary orbit
C	Whether the satellite is in a polar or equatorial orbit
D	The satellite's uplink and downlink frequency bands

9. - E2B07

What is the name of the signal component that carries color information in NTSC video?

Select	Answer
A	Luminance
B	Hue
C	Chroma
D	Spectral intensity

10. - E2C02

Which of the following best describes the term self-spotting? in connection with HF contest operating?

Select	Answer
A	The acceptable practice of manually posting the call signs of stations on a spotting network
B	An automatic method for rapidly zero beating or tuning to a station's frequency before calling that station
C	A manual technique for rapidly zero beating or tuning to a station's frequency before calling that station
D	The often-prohibited practice of posting one's own call sign and frequency on a spotting network

11. - E2D07

What digital protocol is used by APRS?

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

12. - E2E09

Which of the following HF digital modes uses variable-length coding for bandwidth efficiency?

Select	Answer
A	RTTY
B	MT63
C	PACTOR
D	PSK31

13. - E3A04

What do Hepburn maps predict?

Select	Answer
A	Sporadic E propagation
B	Likelihood of rain scatter along cold or warm fronts
C	Locations of auroral reflecting zones
D	Probability of tropospheric propagation

14. - E3B03

What is the best time of day for transequatorial propagation?

Select	Answer
A	Late at night
B	Morning
C	Afternoon or early evening
D	Noon

15. - E3C08

What does the space weather term G5 mean?

Select	Answer
A	Waning sunspot numbers
B	Moderate solar wind
C	An extreme geomagnetic storm
D	Very low solar activity

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	Never use a DC-coupled probe to measure an AC circuit
D	All these choices are correct

17. - E4B11

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

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

18. - E4C12

Which of the following has the largest effect on an SDR receiver's dynamic range?

Select	Answer
A	Anti-aliasing input filter bandwidth
B	RAM speed used for data storage
C	Analog-to-digital converter sample width in bits
D	CPU register width in bits

19. - E4D03

How can intermodulation interference between two repeaters occur?

Select	Answer
A	When the signals from the transmitters are reflected out of phase from airplanes passing overhead
B	When the repeaters are in close proximity and the signals cause feedback in the final amplifier of one or both transmitters
C	When the signals from the transmitters are reflected in phase from airplanes passing overhead
D	When the repeaters are in close proximity and the signals mix in the final amplifier of one or both transmitters

20. - E4E06

What is one type of electrical interference that might be caused by a nearby personal computer?

Select	Answer
A	A clicking noise at intervals of a few seconds
B	A whining type noise that continually pulses off and on
C	A loud AC hum in the audio output of your station receiver
D	The appearance of unstable modulated or unmodulated signals at specific frequencies

21. - E5A06

What is the magnitude of the circulating current within the components of a parallel LC circuit at resonance?

Select	Answer
A	It is at a minimum
B	It equals 1 divided by the quantity 2 times pi, multiplied by the square root of inductance L multiplied by capacitance C
C	It equals 2 multiplied by pi, multiplied by frequency, multiplied by inductance
D	It is at a maximum

22. - E5B06

What is susceptance?

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

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 inductive reactance
C	50 ohms resistance in series with 25 ohms capacitive reactance
D	25 ohms resistance in series with 50 ohms capacitive reactance

24. - E5D03

What is microstrip?

Select	Answer
A	Precision printed circuit conductors above a ground plane that provide constant impedance interconnects at microwave frequencies
B	Miniature coax used for low power applications
C	Short lengths of coax mounted on printed circuit boards to minimize time delay between microwave circuits
D	Lightweight transmission line made of common zip cord

25. - E6A05

How does DC input impedance at the gate of a field-effect transistor compare with the DC input impedance of a bipolar transistor?

Select	Answer
A	They are both high impedance
B	An FET has higher input impedance
C	An FET has lower input impedance
D	They are both low impedance

26. - E6B10

In Figure E6-2, what is the schematic symbol for a light-emitting diode?

Select	Answer
A	5
B	6
C	7
D	1

27. - E6C09

What is a Programmable Logic Device (PLD)?

Select	Answer
A	A logic circuit that can be modified during use
B	A type of transistor whose gain can be changed by digital logic circuits
C	Programmable equipment used for testing digital logic integrated circuits
D	A programmable collection of logic gates and circuits in a single integrated circuit

28. - E6D05

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

Select	Answer
A	Ferrite toroids are easier to use with surface mount technology
B	Ferrite toroids generally have lower initial permeability
C	Ferrite toroids generally require fewer turns to produce a given inductance value
D	Ferrite toroids generally have better temperature stability

29. - E6E05

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

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

30. - E6F04

What is the photovoltaic effect?

Select	Answer
A	The conversion of electrical energy to mechanical energy
B	The tendency of a battery to discharge when exposed to light
C	The conversion of voltage to current when exposed to light
D	The conversion of light to electrical energy

31. - E7A11

What type of logic defines "1" as a high voltage?

Select	Answer
A	Assertive Logic
B	Reverse Logic
C	Positive Logic
D	Negative logic

32. - E7B16

What is the effect of intermodulation products in a linear power amplifier?

Select	Answer
A	Transmission of spurious signals
B	Creation of parasitic oscillations
C	Low efficiency
D	All these choices are correct

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

34. - E7D03

What device is typically used as a stable voltage reference in a linear voltage regulator?

Select	Answer
A	An SCR
B	A varactor diode
C	A tunnel diode
D	A Zener diode

35. - E7E02

What is the function of a reactance modulator?

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

36. - E7F12

Which of the following is an advantage of a Finite Impulse Response (FIR) filter vs an Infinite Impulse Response (IIR) digital filter?

Select	Answer
A	FIR filters can respond faster to impulses
B	FIR filters are easier to implement for a given set of passband rolloff requirements
C	FIR filters can delay all frequency components of the signal by the same amount
D	All these choices are correct

37. - E7G07

What magnitude of voltage gain can be expected from the circuit in Figure E73 when R1 is 10 ohms and RF is 470 ohms?

Select	Answer
A	0.21
B	47
C	94
D	24

38. - E7H15

Which of these functions can be performed by a phase-locked loop?

Select	Answer
A	Comparison of two digital input signals, digital pulse counter
B	Wide-band AF and RF power amplification
C	Frequency synthesis, FM demodulation
D	Photovoltaic conversion, optical coupling

39. - E8A02

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

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

40. - E8B08

What describes Orthogonal Frequency Division Multiplexing?

Select	Answer
A	A digital mode for narrow-band, slow-speed transmissions
B	A frequency modulation technique that uses non-harmonically related frequencies
C	A bandwidth compression technique using Fourier transforms
D	A digital modulation technique using subcarriers at frequencies chosen to avoid intersymbol interference

41. - E8C02

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

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

42. - E8D09

What is considered an acceptable maximum IMD level for an idling PSK signal?

Select	Answer
A	+10 dB
B	+15 dB
C	-20 dB
D	-30 dB

43. - E9A02

What is the effective radiated power relative to a dipole of a repeater station with 150 watts transmitter power output, 2 dB feed line loss, 2.2 dB duplexer loss, and 7 dBd antenna gain?

Select	Answer
A	78.7 watts
B	286 watts
C	420 watts
D	1977 watts

44. - E9B01

In the antenna radiation pattern shown in Figure E9-1, what is the beamwidth?

Select	Answer
A	50 degrees
B	30 degrees
C	25 degrees
D	75 degrees

45. - E9C10

Which of the following describes a Zepp antenna?

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

46. - E9D03

Where should a high Q loading coil be placed to minimize losses in a shortened vertical antenna?

Select	Answer
A	As close to the transmitter as possible
B	Near the center of the vertical radiator
C	As low as possible on the vertical radiator
D	At a voltage node

47. - E9E11

What is the primary purpose of phasing lines when used with an antenna having multiple driven elements?

Select	Answer
A	It allows single-band antennas to operate on other bands
B	It creates a low-angle radiation pattern
C	It ensures that each driven element operates in concert with the others to create the desired antenna pattern
D	It prevents reflected power from traveling back down the feed line and causing harmonic radiation from the transmitter

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

49. - E9G07

On the Smith chart shown in Figure E9-3, what is the only straight line shown?

Select	Answer
A	The reactance axis
B	The resistance axis
C	The current axis
D	The voltage axis

50. - E9H09

What is a Pennant antenna?

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

Figure E6-2

Figure E9-1

Figure E9-3