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

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1. - E0A11

Which of the following injuries can result from using high-power UHF or microwave transmitters?

Select	Answer
A	Localized heating of the body from RF exposure in excess of the MPE limits
B	Hearing loss caused by high voltage corona discharge
C	Ingestion of ozone gas from the cooling system
D	Blood clotting from the intense magnetic field

2. - E1A07

What is the maximum power permitted on the 2200 meter band?

Select	Answer
A	100 watts PEP
B	50 watts PEP
C	5 watts EIRP (Equivalent isotropic radiated power)
D	1 watt EIRP (Equivalent isotropic radiated power)

3. - E1B11

What does PRB-1 require of regulations affecting amateur radio?

Select	Answer
A	Reasonable accommodations of amateur radio must be made
B	Use of wireless devices in a vehicle is exempt from regulation
C	No limitations may be placed on antenna size or placement
D	Amateur radio operations must be permitted in any private residence

4. - E1C03

How do the control operator responsibilities of a station under automatic control differ from one under local control?

Select	Answer
A	Under automatic control there is no control operator
B	Under local control there is no control operator
C	Under automatic control the control operator is not required to be present at the control point
D	Under local control a control operator is not required to be present at a control point

5. - E1D03

What is a space telecommand station?

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

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

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 General, Advanced or Amateur Extra Class operators
D	Only Technician, General, Advanced or Amateur Extra Class operators

8. - E2A11

What type of antenna can be used to minimize the effects of spin modulation and Faraday rotation?

Select	Answer
A	A linearly polarized antenna
B	An isotropic antenna
C	A log-periodic dipole array
D	A circularly polarized antenna

9. - E2B05

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

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

10. - E2C04

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

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

11. - E2D07

What digital protocol is used by APRS?

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

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	Stations take turns on alternate days
D	It depends on the lunar phase

13. - E3A10

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

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

14. - E3B07

What happens to linearly polarized radio waves that split into ordinary and extraordinary waves in the ionosphere?

Select	Answer
A	They become elliptically polarized
B	They become depolarized
C	They become phase locked
D	They are bent toward the magnetic poles

15. - E3C13

What type of polarization is best for ground-wave propagation?

Select	Answer
A	Vertical
B	Horizontal
C	Elliptical
D	Circular

16. - E4A03

Which of the following test instruments is used to display spurious signals and/or intermodulation distortion products generated by an SSB transmitter?

Select	Answer
A	A logic analyzer
B	A wattmeter
C	A spectrum analyzer
D	A time-domain reflectometer

17. - E4B07

What do the subscripts of S parameters represent?

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

18. - E4C03

What is the term for the suppression in an FM receiver of one signal by another stronger signal on the same frequency?

Select	Answer
A	Capture effect
B	Frequency discrimination
C	Desensitization
D	Cross-modulation interference

19. - E4D10

What does a third-order intercept level of 40 dBm mean with respect to receiver performance?

Select	Answer
A	Signals less than 40 dBm will not generate audible third-order intermodulation products
B	A pair of 40 dBm input signals will theoretically generate a third-order intermodulation product that has the same output amplitude as either of the input signals
C	A pair of 1 mW input signals will produce a third-order intermodulation product that is 40 dB stronger than the input signal
D	The receiver can tolerate signals up to 40 dB above the noise floor without producing third-order intermodulation products

20. - E4E01

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

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

21. - E5A09

How is the Q of an RLC parallel resonant circuit calculated?

Select	Answer
A	Resistance divided by the reactance of either the inductance or capacitance
B	Reactance of either the inductance or capacitance divided by the resistance
C	Reactance of the inductance multiplied by the reactance of the capacitance
D	Reactance of either the inductance or capacitance multiplied by the resistance

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

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 2
D	Point 6

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	100 watts
C	70.7 watts
D	200 watts

25. - E6A11

In Figure E6-1, what is the schematic symbol for a P-channel junction FET?

Select	Answer
A	1
B	2
C	6
D	3

26. - E6B03

What type of bias is required for an LED to emit light?

Select	Answer
A	Forward bias
B	Inductive bias
C	Zero bias
D	Reverse bias

27. - E6C03

What is tri-state logic?

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

28. - E6D13

What is the primary cause of inductor self-resonance?

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

29. - E6E10

What advantage does surface-mount technology offer at RF compared to using through-hole components?

Select	Answer
A	All these choices are correct
B	Shorter circuit-board traces
C	Smaller circuit area
D	Components have less parasitic inductance and capacitance

30. - E6F03

What is the most common configuration of an optoisolator or optocoupler?

Select	Answer
A	An amplitude modulated helium-neon laser
B	A frequency modulated helium-neon laser
C	An LED and a phototransistor
D	A lens and a photomultiplier

31. - E7A03

Which of the following can divide the frequency of a pulse train by 2?

Select	Answer
A	A multiplexer
B	An XOR gate
C	A flip-flop
D	An OR gate

32. - E7B15

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

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

33. - E7C10

Which of the following filters would be the best choice for use in a 2 meter band repeater duplexer?

Select	Answer
A	An L-C filter
B	A crystal filter
C	A DSP filter
D	A cavity filter

34. - E7D01

How does a linear electronic voltage regulator work?

Select	Answer
A	The control element duty cycle is proportional to the line or load conditions
B	The conduction of a control element is varied to maintain a constant output voltage
C	It has a ramp voltage as its output
D	It eliminates the need for a pass transistor

35. - E7E11

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

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

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	All these choices are correct
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	FIR filters can respond faster to impulses

37. - E7G05

How can unwanted ringing and audio instability be prevented in an op-amp RC audio filter circuit?

Select	Answer
A	Restrict both gain and Q
B	Restrict gain but increase Q
C	Increase both gain and Q
D	Restrict Q but increase gain

38. - E7H15

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

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

39. - E8A03

What type of wave does a Fourier analysis show to be made up of sine waves of a given fundamental frequency plus all its harmonics?

Select	Answer
A	A sine wave
B	A square wave
C	A cosine wave
D	A sawtooth wave

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	0.3
B	1000
C	3
D	3000

41. - E8C09

Which digital code allows only one bit to change between sequential code values?

Select	Answer
A	Binary Coded Decimal Code
B	Extended Binary Coded Decimal Interchange Code
C	Gray code
D	Excess 3 code

42. - E8D04

What is the primary effect of extremely short rise or fall time on a CW signal?

Select	Answer
A	The generation of key clicks
B	Limits data speed
C	More difficult to copy
D	The generation of RF harmonics

43. - E9A10

Which of the following improves the efficiency of a ground-mounted quarter-wave vertical antenna?

Select	Answer
A	All these choices are correct
B	Shortening the radiating element
C	Isolating the coax shield from ground
D	Installing a radial system

44. - E9B05

What type of antenna pattern is shown in Figure E9-2?

Select	Answer
A	Polarization
B	Elevation
C	Radiation resistance
D	Azimuth

45. - E9C06

What is the effect of adding a terminating resistor to a rhombic antenna?

Select	Answer
A	It reflects the standing waves on the antenna elements back to the transmitter
B	It changes the radiation pattern from horizontal to vertical polarization
C	It changes the radiation pattern from bidirectional to unidirectional
D	It decreases the ground loss

46. - E9D02

How can linearly polarized Yagi antennas be used to produce circular polarization?

Select	Answer
A	Arrange two Yagis collinear to each other with the driven elements fed 180 degrees out of phase
B	Stack two Yagis fed 90 degrees out of phase to form an array with the respective elements in parallel planes
C	Arrange two Yagis perpendicular to each other with the driven elements at the same point on the boom fed 90 degrees out of phase
D	Stack two Yagis fed in phase to form an array with the respective elements in parallel planes

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	50 ohms
C	450 ohms
D	62 ohms

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	8.5 meters
B	7.0 meters
C	13.3 meters
D	10.6 meters

49. - E9G08

What is the process of normalization with regard to a Smith chart?

Select	Answer
A	Reassigning prime center with regard to the reactance axis
B	Reassigning impedance values with regard to the prime center
C	Reassigning resistance values with regard to the reactance axis
D	Reassigning reactance values with regard to the resistance axis

50. - E9H04

What is an advantage of placing a grounded electrostatic shield around a small loop direction-finding antenna?

Select	Answer
A	It adds capacitive loading, increasing the bandwidth of the antenna
B	It increases signal strength by providing a better match to the feed line
C	It eliminates tracking errors caused by strong out-of-band signals
D	It eliminates unbalanced capacitive coupling to the surroundings, improving the nulls

Figure E5-1

Figure E6-1

Figure E9-2