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

2. - E1A01

Which of the following carrier frequencies is illegal for LSB AFSK emissions on the 17 meter band RTTY and data segment of 18.068 to 18.110 MHz?

Select	Answer
A	18.100 MHz
B	18.110 MHz
C	18.068 MHz
D	18.107 MHz

3. - E1B07

To what type of regulations does PRB-1 apply?

Select	Answer
A	FAA tower height limits
B	Homeowners associations
C	Use of wireless devices in vehicles
D	State and local zoning

4. - E1C02

Which of the following types of communications may be transmitted to amateur stations in foreign countries?

Select	Answer
A	Messages intended for users of the maritime satellite service
B	Communications incidental to the purpose of the amateur service and remarks of a personal nature
C	All these choices are correct
D	Business-related messages for non-profit organizations

5. - E1D10

Which amateur stations are eligible to be telecommand stations of space stations (subject to the privileges of the class of operator license held by the control operator of the station)?

Select	Answer
A	Any amateur station so designated by the ITU
B	All these choices are correct
C	Any amateur station so designated by the space station licensee
D	Any amateur station designated by NASA

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. - E1F10

Who may be the control operator of an auxiliary station?

Select	Answer
A	Only Technician, General, Advanced or Amateur Extra Class operators
B	Any licensed amateur operator
C	Only Amateur Extra Class operators
D	Only 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	An isotropic antenna
B	A log-periodic dipole array
C	A linearly polarized antenna
D	A circularly polarized antenna

9. - E2B07

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

Select	Answer
A	Spectral intensity
B	Hue
C	Chroma
D	Luminance

10. - E2C03

From which of the following bands is amateur radio contesting generally excluded?

Select	Answer
A	2 meters
B	6 meters
C	30 meters
D	33 centimeters

11. - E2D06

Which of the following describes a method of establishing EME contacts?

Select	Answer
A	Time synchronous transmissions alternately from each station
B	Storing and forwarding digital messages
C	High-speed CW identification to avoid fading
D	Judging optimum transmission times by monitoring beacons reflected from the moon

12. - E2E10

Which of these digital modes has the narrowest bandwidth?

Select	Answer
A	PSK31
B	300-baud packet
C	170 Hz shift, 45-baud RTTY
D	MFSK16

13. - E3A01

What is the approximate maximum separation measured along the surface of the Earth between two stations communicating by EME?

Select	Answer
A	5000 miles, if the moon is at perigee
B	500 miles, if the moon is at perigee
C	2000 miles, if the moon is at apogee
D	12,000 miles, if the moon is visible by both stations

14. - E3B04

What is meant by the terms "extraordinary" and "ordinary" waves?

Select	Answer
A	Independent waves created in the ionosphere that are elliptically polarized
B	Refracted rays and reflected waves
C	Extraordinary waves describe rare long-skip propagation compared to ordinary waves, which travel shorter distances
D	Long-path and short-path waves

15. - E3C14

Why does the radio-path horizon distance exceed the geometric horizon?

Select	Answer
A	E-region skip
B	D-region skip
C	Downward bending due to density variations in the atmosphere
D	Due to the Doppler effect

16. - E4A10

Which of the following displays multiple digital signal states simultaneously?

Select	Answer
A	Logic analyzer
B	Network analyzer
C	Modulation monitor
D	Bit error rate tester

17. - E4B09

What is indicated if the current reading on an RF ammeter placed in series with the antenna feed line of a transmitter increases as the transmitter is tuned to resonance?

Select	Answer
A	There is an impedance mismatch between the antenna and feed line
B	The transmitter is not properly neutralized
C	There is possibly a short to ground in the feed line
D	There is more power going into the antenna

18. - E4C14

What transmit frequency might generate an image response signal in a receiver tuned to 14.300 MHz and that uses a 455 kHz IF frequency?

Select	Answer
A	13.845 MHz
B	14.445 MHz
C	15.210 MHz
D	14.755 MHz

19. - E4D11

Why are odd-order intermodulation products, created within a receiver, of particular interest compared to other products?

Select	Answer
A	Odd-order intermodulation produces three products for every input signal within the band of interest
B	Odd-order products overload the IF filters
C	Odd-order products are an indication of poor image rejection
D	Odd-order products of two signals in the band of interest are also likely to be within the band

20. - E4E03

Which of the following signals might a receiver noise blanker be able to remove from desired signals?

Select	Answer
A	Signals that appear across a wide bandwidth
B	Signals that have a sharply peaked frequency distribution
C	Signals that appear at one IF but not another
D	Signals that are constant at all IF levels

21. - E5A12

What is the half-power bandwidth of a resonant circuit that has a resonant frequency of 3.7 MHz and a Q of 118?

Select	Answer
A	15.7 kHz
B	436.6 kHz
C	31.4 kHz
D	218.3 kHz

22. - E5B06

What is susceptance?

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

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 6
B	Point 5
C	Point 2
D	Point 4

24. - E5D07

How many watts are consumed in a circuit having a power factor of 0.71 if the apparent power is 500VA?

Select	Answer
A	252 W
B	1.42 mW
C	704 W
D	355 W

25. - E6A01

In what application is gallium arsenide used as a semiconductor material?

Select	Answer
A	In high-current rectifier circuits
B	In high-power audio circuits
C	In very low-frequency RF circuits
D	In microwave circuits

26. - E6B01

What is the most useful characteristic of a Zener diode?

Select	Answer
A	A constant voltage drop under conditions of varying current
B	An internal capacitance that varies with the applied voltage
C	A negative resistance region
D	A constant current drop under conditions of varying voltage

27. - E6C11

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

Select	Answer
A	4
B	6
C	5
D	2

28. - E6D11

Which type of core material decreases inductance when inserted into a coil?

Select	Answer
A	Ferrite
B	Ceramic
C	Powdered iron
D	Brass

29. - E6E04

Which is the most common input and output impedance of circuits that use MMICs?

Select	Answer
A	10 ohms
B	50 ohms
C	450 ohms
D	300 ohms

30. - E6F06

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

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

31. - E7A10

What is a truth table?

Select	Answer
A	A table of logic symbols that indicate the high logic states of an op-amp
B	A diagram showing logic states when the digital device output is true
C	A list of inputs and corresponding outputs for a digital device
D	A table of logic symbols that indicate the logic states of an op-amp

32. - E7B03

Which of the following components form the output of a class D amplifier circuit?

Select	Answer
A	A low-pass filter to remove switching signal components
B	A high-pass filter to compensate for low gain at low frequencies
C	A temperature compensating load resistor to improve linearity
D	A matched load resistor to prevent damage by switching transients

33. - E7C09

What is a crystal lattice filter?

Select	Answer
A	A filter using lattice-shaped quartz crystals for high-Q performance
B	A power supply filter made with interlaced quartz crystals
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. - 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 inverter design does not require any output filtering
B	It uses a large power factor compensation capacitor to recover power from the unused portion of the AC cycle
C	The high frequency inverter design uses much smaller transformers and filter components for an equivalent power output
D	It uses a diode bridge rectifier for increased output

35. - E7E03

What is a frequency discriminator stage in a FM receiver?

Select	Answer
A	An FM generator circuit
B	A circuit for detecting FM signals
C	An automatic band-switching circuit
D	A circuit for filtering two closely adjacent signals

36. - E7F06

What is the minimum number of bits required for an analog-to-digital converter to sample a signal with a range of 1 volt at a resolution of 1 millivolt?

Select	Answer
A	10 bits
B	4 bits
C	6 bits
D	8 bits

37. - E7G01

What is the typical output impedance of an op-amp?

Select	Answer
A	Very high
B	1000 ohms
C	100 ohms
D	Very low

38. - E7H11

What are the major spectral impurity components of direct digital synthesizers?

Select	Answer
A	Broadband noise
B	Digital conversion noise
C	Spurious signals at discrete frequencies
D	Nyquist limit noise

39. - E8A04

What is "dither" with respect to analog-to-digital converters?

Select	Answer
A	An abnormal condition where the converter cannot settle on a value to represent the signal
B	An error caused by irregular quantization step size
C	A small amount of noise added to the input signal to allow more precise representation of a signal over time
D	A method of decimation by randomly skipping samples

40. - E8B05

What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus-or-minus 5 kHz when the maximum modulation frequency is 3 kHz?

Select	Answer
A	0.167
B	0.6
C	1.67
D	60

41. - E8C08

How does ARQ accomplish error correction?

Select	Answer
A	Special polynomial codes provide automatic correction
B	If errors are detected, a retransmission is requested
C	Special binary codes provide automatic correction
D	If errors are detected, redundant data is substituted

42. - E8D11

What is one advantage of using ASCII code for data communications?

Select	Answer
A	It includes built-in error correction features
B	It contains fewer information bits per character than any other code
C	It is possible to transmit both upper and lower case text
D	It uses one character as a shift code to send numeric and special characters

43. - E9A11

Which of the following factors determines ground losses for a ground-mounted vertical antenna operating in the 3 MHz to 30 MHz range?

Select	Answer
A	Distance from the transmitter
B	The standing wave ratio
C	Take-off angle
D	Soil conductivity

44. - E9B07

How does the total amount of radiation emitted by a directional gain antenna compare with the total amount of radiation emitted from a theoretical isotropic antenna, assuming each is driven by the same amount of power?

Select	Answer
A	They are the same
B	The radiation from the isotropic antenna is 2.15 dB stronger than that from the directional antenna
C	The total amount of radiation from the directional antenna is stronger by its front-to-back ratio
D	The total amount of radiation from the directional antenna is increased by the gain of the antenna

45. - E9C14

How does the performance of a horizontally polarized antenna mounted on the side of a hill compare with the same antenna mounted on flat ground?

Select	Answer
A	The main lobe takeoff angle increases in the downhill direction
B	The main lobe takeoff angle decreases in the downhill direction
C	The horizontal beamwidth increases in the uphill direction
D	The horizontal beamwidth decreases in the downhill direction

46. - E9D03

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

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

47. - E9E01

What system matches a higher-impedance transmission line to a lower-impedance antenna by connecting the line to the driven element in two places spaced a fraction of a wavelength each side of element center?

Select	Answer
A	The delta matching system
B	The stub matching system
C	The gamma matching system
D	The omega matching system

48. - E9F10

What impedance does a 1/8-wavelength transmission line present to a generator when the line is shorted at the far end?

Select	Answer
A	A capacitive reactance
B	An inductive reactance
C	The same as the characteristic impedance of the line
D	Zero

49. - E9G06

On the Smith chart shown in Figure E9-3, what is the name for the large outer circle on which the reactance arcs terminate?

Select	Answer
A	Reactance axis
B	Polar axis
C	Impedance axis
D	Prime axis

50. - E9H08

What is the function of a sense antenna?

Select	Answer
A	It increases the sensitivity of a DF antenna array
B	It provides diversity reception that cancels multipath signals
C	It allows DF antennas to receive signals at different vertical angles
D	It modifies the pattern of a DF antenna array to provide a null in one direction

Figure E5-1

Figure E6-3

Figure E9-3