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

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1. - E0A02

When evaluating RF exposure levels from your station at a neighbor's home, what must you do?

Select	Answer
A	Ensure signals from your station are less than the controlled Maximum Permitted Emission (MPE) limits
B	Ensure signals from your station are less than the controlled Maximum Permitted Exposure (MPE) limits
C	Ensure signals from your station are less than the uncontrolled Maximum Permitted Emission (MPE) limits
D	Ensure signals from your station are less than the uncontrolled Maximum Permitted Exposure (MPE) limits

2. - E1A04

With your transceiver displaying the carrier frequency of phone signals, you hear a DX station calling CQ on 3.601 MHz LSB. Is it legal to return the call using lower sideband on the same frequency?

Select	Answer
A	Yes, because the DX station initiated the contact
B	No, the sideband will extend beyond the edge of the phone band segment
C	Yes, because the displayed frequency is within the 75 meter phone band segment
D	No, U.S. stations are not permitted to use phone emissions below 3.610 MHz

3. - E1B10

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

Select	Answer
A	Military Auxiliary Radio System (MARS) channels
B	Specific local government 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. - E1C12

On what portion of the 630 meter band are phone emissions permitted?

Select	Answer
A	Only the bottom 3 kHz
B	The entire band
C	Only the top 3 kHz
D	None

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

6. - E1E01

For which types of out-of-pocket expenses do the Part 97 rules state that VEs and VECs may be reimbursed?

Select	Answer
A	Teaching an amateur operator license examination preparation course
B	Providing amateur operator license examination preparation training materials
C	Preparing, processing, administering, and coordinating an examination for an amateur radio operator license
D	No expenses are authorized for reimbursement

7. - E1F02

What privileges are authorized in the U.S. to persons holding an amateur service license granted by the government of Canada?

Select	Answer
A	All privileges of the Amateur Extra Class license
B	The operating terms and conditions of the Canadian amateur service license, not to exceed U.S. Amateur Extra Class license privileges
C	None, they must obtain a U.S. license
D	Full privileges, up to and including those of the Amateur Extra Class license, on the 80, 40, 20, 15, and 10 meter bands

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	All these choices are correct
D	PSK and packet

9. - E2B08

What technique allows commercial analog TV receivers to be used for fast-scan TV operations on the 70 cm band?

Select	Answer
A	Transmitting on channels shared with cable TV
B	Using USB and demodulating the signal with a computer sound card
C	Using converted satellite TV dishes
D	Transmitting on the abandoned TV channel 2

10. - E2C04

Which of the following frequencies are sometimes used for amateur radio mesh networks?

Select	Answer
A	HF frequencies where digital communications are permitted
B	The 60 meter band channel centered on 5373 kHz
C	Frequencies shared with various unlicensed wireless data services
D	Cable TV channels 41 through 43

11. - E2D07

What digital protocol is used by APRS?

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

12. - E2E05

Which of these digital modes does not support keyboard-to-keyboard operation?

Select	Answer
A	MFSK
B	PSK31
C	RTTY
D	PACTOR

13. - E3A10

Which type of atmospheric structure can create a path for microwave propagation?

Select	Answer
A	Wind shear
B	The jet stream
C	Temperature inversion
D	Dust devil

14. - E3B11

At what time of day can sporadic E propagation occur?

Select	Answer
A	Only in hours of darkness
B	Any time
C	Only around sunset and sunrise
D	Only around sunset

15. - E3C09

How does the intensity of an X3 flare compare to that of an X2 flare?

Select	Answer
A	Twice as great
B	50 percent greater
C	Four times as great
D	10 percent greater

16. - E4A09

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

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

17. - E4B10

Which of the following methods measures intermodulation distortion in an SSB transmitter?

Select	Answer
A	Modulate the transmitter using two RF signals having harmonically related frequencies and observe the RF output with a logic analyzer
B	Modulate the transmitter using two RF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer
C	Modulate the transmitter using two AF signals having harmonically related frequencies and observe the RF output with a peak reading wattmeter
D	Modulate the transmitter using two AF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer

18. - E4C15

What is reciprocal mixing?

Select	Answer
A	Local oscillator phase noise mixing with adjacent strong signals to create interference to desired signals
B	Two out-of-band signals mixing to generate an in-band spurious signal
C	Two digital signals combining from alternate time slots
D	In-phase signals cancelling in a mixer resulting in loss of receiver sensitivity

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	Intermodulation
B	Amplifier desensitization
C	Neutralization
D	Adjacent channel interference

20. - E4E07

Which of the following can cause shielded cables to radiate or receive interference?

Select	Answer
A	Low inductance ground connections at both ends of the shield
B	Tying all ground connections to a common point resulting in differential-mode currents in the shield
C	Common-mode currents on the shield and conductors
D	Use of braided shielding material

21. - E5A06

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

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

22. - E5B09

What is the relationship between the AC current through a capacitor and the voltage across a capacitor?

Select	Answer
A	Voltage and current are in phase
B	Voltage and current are 180 degrees out of phase
C	Voltage leads current by 90 degrees
D	Current leads voltage by 90 degrees

23. - E5C08

What coordinate system is often used to display the phase angle of a circuit containing resistance, inductive and/or capacitive reactance?

Select	Answer
A	Polar coordinates
B	Faraday grid
C	Elliptical coordinates
D	Maidenhead grid

24. - E5D09

What happens to reactive power in an AC circuit that has both ideal inductors and ideal capacitors?

Select	Answer
A	It is dissipated as heat in the circuit
B	It is dissipated in the formation of inductive and capacitive fields
C	It is repeatedly exchanged between the associated magnetic and electric fields, but is not dissipated
D	It is dissipated as kinetic energy in the circuit

25. - E6A12

Why do many MOSFET devices have internally connected Zener diodes on the gates?

Select	Answer
A	To reduce the chance of static damage to the gate
B	To provide a voltage reference for the correct amount of reverse-bias gate voltage
C	To keep the gate voltage within specifications and prevent the device from overheating
D	To protect the substrate from excessive voltages

26. - E6B04

What type of semiconductor device is designed for use as a voltage-controlled capacitor?

Select	Answer
A	Varactor diode
B	Tunnel diode
C	Zener diode
D	Silicon-controlled rectifier

27. - E6C02

What happens when the level of a comparator's input signal crosses the threshold?

Select	Answer
A	The feedback loop becomes unstable
B	The comparator enters latch-up
C	The comparator changes its output state
D	The IC input can be damaged

28. - E6D05

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

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

29. - E6E12

Why are DIP through-hole package ICs not typically used at UHF and higher frequencies?

Select	Answer
A	Excessive lead length
B	Epoxy coating is conductive above 300 MHz
C	Too many pins
D	Unsuitable for combining analog and digital signals

30. - E6F05

Which describes an optical shaft encoder?

Select	Answer
A	A digital encryption device often used to encrypt spacecraft control signals
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 device that detects rotation of a control by interrupting a light source with a patterned wheel

31. - E7A11

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

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

32. - E7B11

In Figure E7-1, what is the purpose of R3?

Select	Answer
A	Output load resistor
B	Self bias
C	Emitter bypass
D	Fixed bias

33. - E7C04

How does an impedance-matching circuit transform a complex impedance to a resistive impedance?

Select	Answer
A	It introduces transconductance to cancel the reactive part of impedance
B	It cancels the reactive part of the impedance and changes the resistive part to a desired value
C	Reactive currents are dissipated in matched resistances
D	It introduces negative resistance to cancel the resistive part of impedance

34. - E7D12

What is the dropout voltage of an analog voltage regulator?

Select	Answer
A	Maximum output voltage drops when the input voltage is varied over its specified range
B	Maximum that the output voltage may decrease at rated load
C	Minimum input-to-output voltage required to maintain regulation
D	Minimum input voltage for rated power dissipation

35. - E7E11

Which type of detector circuit is used for demodulating SSB signals?

Select	Answer
A	Product detector
B	Phase detector
C	Discriminator
D	Phase comparator

36. - E7F01

What is meant by direct digital conversion as applied to software defined radios?

Select	Answer
A	A switching mixer is used to generate I and Q signals directly from the RF input
B	Software is converted from source code to object code during operation of the receiver
C	Incoming RF is converted to a control voltage for a voltage controlled oscillator
D	Incoming RF is digitized by an analog-to-digital converter without being mixed with a local oscillator signal

37. - E7G04

What is meant by the "op-amp input offset voltage"?

Select	Answer
A	The differential input voltage needed to bring the open loop output voltage to zero
B	The potential between the amplifier input terminals of the op-amp in an open loop condition
C	The output voltage of the op-amp minus its input voltage
D	The difference between the output voltage of the op-amp and the input voltage required in the immediately following stage

38. - E7H12

Which of the following must be done to ensure that a crystal oscillator provides the frequency specified by the crystal manufacturer?

Select	Answer
A	Bias the crystal at a specified voltage
B	Provide the crystal with a specified parallel inductance
C	Bias the crystal at a specified current
D	Provide the crystal with a specified parallel capacitance

39. - E8A11

Which of the following is a measure of the quality of an analog-to-digital converter?

Select	Answer
A	Reciprocal mixing
B	Total harmonic distortion
C	Peak envelope power
D	Power factor

40. - E8B01

What is the modulation index of an FM signal?

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

41. - E8C06

What is the bandwidth of a 170-hertz shift, 300-baud ASCII transmission?

Select	Answer
A	0.3 kHz
B	1.0 kHz
C	0.1 Hz
D	0.5 kHz

42. - E8D07

What is a common cause of overmodulation of AFSK signals?

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

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	286 watts
B	1977 watts
C	78.7 watts
D	420 watts

44. - E9B04

What is the front-to-back ratio of the radiation pattern shown in Figure E92?

Select	Answer
A	28 dB
B	15 dB
C	38 dB
D	3 dB

45. - E9C05

Which of the following is a type of OCFD antenna?

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

46. - E9D05

What usually occurs if a Yagi antenna is designed solely for maximum forward gain?

Select	Answer
A	The SWR is reduced
B	The front-to-back ratio increases
C	The frequency response is widened over the whole frequency band
D	The front-to-back ratio decreases

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	62 ohms
B	450 ohms
C	75 ohms
D	50 ohms

48. - E9F03

Why is the physical length of a coaxial cable transmission line shorter than its electrical length?

Select	Answer
A	Skin effect is less pronounced in the coaxial cable
B	Electrical signals move more slowly in a coaxial cable than in air
C	The surge impedance is higher in a parallel feed line
D	The characteristic impedance is higher in a parallel feed line

49. - E9G07

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

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

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 four-element, high-gain vertical array invented by George Pennant
C	A small, vertically oriented receiving antenna consisting of a triangular loop terminated in approximately 900 ohms
D	A stealth antenna built to look like a flagpole

Figure E7-1

Figure E9-3