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

2. - E1A03

What is the maximum legal carrier frequency on the 20 meter band for transmitting USB AFSK digital signals having a 1 kHz bandwidth?

Select	Answer
A	14.070 MHz
B	14.149 MHz
C	14.100 MHz
D	14.349 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	All amateur service frequencies authorized to the control operator
C	Specific segments in the amateur service MF, HF, VHF and UHF bands
D	Specific local government channels

4. - E1C13

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

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

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

6. - E1E03

What is a Volunteer Examiner Coordinator?

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

7. - E1F08

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

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

8. - E2A06

What are Keplerian elements?

Select	Answer
A	Encrypting codes used for spread spectrum modulation
B	High-emission heater filaments used in magnetron tubes
C	Phase reversing elements in a Yagi antenna
D	Parameters that define the orbit of a satellite

9. - E2B03

How is an interlaced scanning pattern generated in a fast-scan (NTSC) television system?

Select	Answer
A	By scanning two fields simultaneously
B	By scanning odd numbered lines in one field and even numbered lines in the next
C	By scanning each field from bottom to top
D	By scanning lines from left to right in one field and right to left in the next

10. - E2C02

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

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

11. - E2D06

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

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

12. - E2E10

Which of these digital modes has the narrowest bandwidth?

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

13. - E3A13

Which of these emission modes is best for auroral propagation?

Select	Answer
A	SSB
B	FM
C	CW
D	RTTY

14. - E3B05

Which amateur bands typically support long-path propagation?

Select	Answer
A	6 meters to 2 meters
B	Only 30 meters to 10 meters
C	160 meters to 10 meters
D	Only 160 meters to 40 meters

15. - E3C10

What does the 304A solar parameter measure?

Select	Answer
A	The solar emission at 304 GHz, correlated to x-ray flare levels
B	UV emissions at 304 angstroms, correlated to the solar flux index
C	The ratio of x-ray flux to radio flux, correlated to sunspot number
D	The solar wind velocity at 304 degrees from the solar equator, correlated to solar activity

16. - E4A08

Which of the following measures SWR?

Select	Answer
A	A spectrum analyzer
B	An ohmmeter
C	A Q meter
D	An antenna analyzer

17. - E4B07

What do the subscripts of S parameters represent?

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

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

19. - E4D12

What is the term for the reduction in receiver sensitivity caused by a strong signal near the received frequency?

Select	Answer
A	Quieting
B	Squelch gain rollback
C	Cross-modulation interference
D	Desensitization

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	Received CW signals will appear to be modulated at the DSP clock frequency
C	Removal of the CW signal as well as the interfering carrier
D	Ringing in the DSP filter will completely remove the spaces between the CW characters

21. - E5A14

What is the resonant frequency of an RLC circuit if R is 22 ohms, L is 50 microhenries and C is 40 picofarads?

Select	Answer
A	44.72 MHz
B	3.56 MHz
C	1.78 MHz
D	22.36 MHz

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. - 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	Maidenhead grid
B	Elliptical coordinates
C	Polar coordinates
D	Faraday grid

24. - E5D03

What is microstrip?

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

25. - E6A11

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

Select	Answer
A	2
B	1
C	6
D	3

26. - E6B07

What is the failure mechanism when a junction diode fails due to excessive current?

Select	Answer
A	Excessive inverse voltage
B	Excessive junction temperature
C	Insufficient forward voltage
D	Charge carrier depletion

27. - E6C03

What is tri-state logic?

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

28. - E6D12

What is inductor saturation?

Select	Answer
A	The ability of the inductor's core to store magnetic energy has been exceeded
B	The inductor's voltage rating is exceeded causing a flashover
C	The inductor windings are over-coupled
D	Adjacent inductors become over-coupled

29. - E6E02

Which of the following device packages is a through-hole type?

Select	Answer
A	Ball grid array
B	SOT
C	DIP
D	PLCC

30. - E6F08

Why are optoisolators often used in conjunction with solid-state circuits when switching 120 VAC?

Select	Answer
A	Optoisolators eliminate the effects of reflected light in the control circuit
B	Optoisolators provide impedance matching between the control circuit and power circuit
C	Optoisolators provide a very high degree of electrical isolation between a control circuit and the circuit being switched
D	Optoisolators provide a low impedance link between a control circuit and a power circuit

31. - E7A02

What is the function of a decade counter?

Select	Answer
A	It decodes a decimal number for display on a seven-segment LED display
B	It decodes a binary number for display on a seven-segment LED display
C	It produces 10 output pulses for every input pulse
D	It produces one output pulse for every 10 input pulses

32. - E7B01

For what portion of the signal cycle does each active element in a push-pull Class AB amplifier conduct?

Select	Answer
A	The entire cycle
B	More than 180 degrees but less than 360 degrees
C	Exactly 180 degrees
D	Less than 180 degrees

33. - E7C10

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

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

34. - E7D12

What is the dropout voltage of an analog voltage regulator?

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

35. - E7E05

What circuit is added to an FM transmitter to boost the higher audio frequencies?

Select	Answer
A	A de-emphasis network
B	A pre-emphasis network
C	A heterodyne enhancer
D	A heterodyne suppressor

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 four times the rate of the highest frequency component of the signal
C	At least twice the rate of the highest frequency component of the signal
D	At the same rate as the highest frequency component of the signal

37. - E7G12

What is an operational amplifier?

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

38. - E7H13

Which of the following is a technique for providing highly accurate and stable oscillators needed for microwave transmission and reception?

Select	Answer
A	Use a temperature-controlled high Q dielectric resonator
B	All these choices are correct
C	Use a GPS signal reference
D	Use a rubidium stabilized reference oscillator

39. - E8A08

Why would a direct or flash conversion analog-to-digital converter be useful for a software defined radio?

Select	Answer
A	Very low power consumption decreases frequency drift
B	All these choices are correct
C	Very high speed allows digitizing high frequencies
D	Immunity to out-of-sequence coding reduces spurious responses

40. - E8B10

What is frequency division multiplexing?

Select	Answer
A	Two or more information streams are merged into a digital combiner, which then pulse position modulates the transmitter
B	Two or more information streams are merged into a baseband, which then modulates the transmitter
C	The transmitted signal jumps from band to band at a predetermined rate
D	The transmitted signal is divided into packets of information

41. - E8C10

How may data rate be increased without increasing bandwidth?

Select	Answer
A	It is impossible
B	Using a more efficient digital code
C	Increasing analog-to-digital conversion resolution
D	Using forward error correction

42. - E8D03

How does the spread spectrum technique of frequency hopping work?

Select	Answer
A	If interference is detected by the receiver it will signal the transmitter to wait until the frequency is clear
B	If interference is detected by the receiver it will signal the transmitter to change frequencies
C	A binary bit stream is used to shift the phase of an RF carrier very rapidly in a pseudorandom sequence
D	The frequency of the transmitted signal is changed very rapidly according to a pseudorandom sequence also used by the receiving station

43. - E9A03

What is the radiation resistance of an antenna?

Select	Answer
A	The specific impedance of the antenna
B	The combined losses of the antenna elements and feed line
C	The resistance in the atmosphere that an antenna must overcome to be able to radiate a signal
D	The value of a resistance that would dissipate the same amount of power as that radiated from an antenna

44. - E9B01

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

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

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

46. - E9D05

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

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

47. - E9E11

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

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

48. - E9F11

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

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

49. - E9G11

How are the wavelength scales on a Smith chart calibrated?

Select	Answer
A	In fractions of transmission line electrical wavelength
B	In fractions of transmission line electrical frequency
C	In fractions of antenna electrical wavelength
D	In fractions of antenna electrical frequency

50. - E9H08

What is the function of a sense antenna?

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

Figure E6-1

Figure E9-1