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

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1. - E0A05

What is one of the potential hazards of operating in the amateur radio microwave bands?

Select	Answer
A	The high gain antennas commonly used can result in high exposure levels
B	The extremely high frequency energy can damage the joints of antenna structures
C	Microwaves are ionizing radiation
D	Microwaves often travel long distances by ionospheric reflection

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	14.149 MHz
B	14.070 MHz
C	14.100 MHz
D	14.349 MHz

3. - E1B12

What must the control operator of a repeater operating in the 70 cm band do if a radiolocation system experiences interference from that repeater?

Select	Answer
A	Reduce the repeater antenna HAAT (Height Above Average Terrain)
B	File an FAA NOTAM (Notice to Airmen) with the repeater system's ERP, call sign, and six-character grid locator
C	All these choices are correct
D	Cease operation or make changes to the repeater to mitigate the interference

4. - E1C02

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

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

5. - E1D08

Which VHF amateur bands have frequencies authorized for space stations?

Select	Answer
A	6 meters, 2 meters, and 1.25 meters
B	2 meters
C	6 meters and 2 meters
D	2 meters and 1.25 meters

6. - E1E04

Which of the following best describes the Volunteer Examiner accreditation process?

Select	Answer
A	Each General, Advanced and Amateur Extra Class operator is automatically accredited as a VE when the license is granted
B	The prospective VE obtains accreditation from the FCC
C	The amateur operator applying must pass a VE examination administered by the FCC Enforcement Bureau
D	The procedure by which a VEC confirms that the VE applicant meets FCC requirements to serve as an examiner

7. - E1F09

Which of the following conditions apply when transmitting spread spectrum emissions?

Select	Answer
A	The transmitting station must be in an area regulated by the FCC or in a country that permits SS emissions
B	A station transmitting SS emission must not cause harmful interference to other stations employing other authorized emissions
C	The transmission must not be used to obscure the meaning of any communication
D	All these choices are correct

8. - E2A12

What is the purpose of digital store-and-forward functions on an amateur radio satellite?

Select	Answer
A	To upload operational software for the transponder
B	To relay messages between satellites
C	To delay download of telemetry between satellites
D	To store digital messages in the satellite for later download by other stations

9. - E2B11

What is the function of the Vertical Interval Signaling (VIS) code sent as part of an SSTV transmission?

Select	Answer
A	To identify the call sign of the station transmitting
B	To provide vertical synchronization
C	To lock the color burst oscillator in color SSTV images
D	To identify the SSTV mode being used

10. - E2C07

What is the Cabrillo format?

Select	Answer
A	A method of exchanging information during a contest QSO
B	The most common set of contest rules
C	The rules of order for meetings between contest sponsors
D	A standard for submission of electronic contest logs

11. - E2D09

What type of modulation is used for JT65 contacts?

Select	Answer
A	IEEE 802.11
B	Multi-tone AFSK
C	RTTY
D	PSK

12. - E2E05

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

Select	Answer
A	RTTY
B	MFSK
C	PACTOR
D	PSK31

13. - E3A09

Which of the following frequency ranges is most suited for meteor scatter communications?

Select	Answer
A	28 MHz - 148 MHz
B	10 MHz - 14 MHz
C	220 MHz - 450 MHz
D	1.8 MHz - 1.9 MHz

14. - E3B06

Which of the following amateur bands most frequently provides long-path propagation?

Select	Answer
A	20 meters
B	80 meters
C	6 meters
D	10 meters

15. - E3C10

What does the 304A solar parameter measure?

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

16. - E4A08

Which of the following measures SWR?

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

17. - E4B01

Which of the following factors most affects the accuracy of a frequency counter?

Select	Answer
A	Temperature coefficient of the logic
B	Input attenuator accuracy
C	Time base accuracy
D	Decade divider accuracy

18. - E4C06

A CW receiver with the AGC off has an equivalent input noise power density of -174 dBm/Hz. What would be the level of an unmodulated carrier input to this receiver that would yield an audio output SNR of 0 dB in a 400 Hz noise bandwidth?

Select	Answer
A	-174 dBm
B	-164 dBm
C	-148 dBm
D	-155 dBm

19. - E4D12

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

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

20. - E4E10

What might be the cause of a loud roaring or buzzing AC line interference that comes and goes at intervals?

Select	Answer
A	A malfunctioning illuminated advertising display
B	All these choices are correct
C	A defective doorbell or doorbell transformer inside a nearby residence
D	Arcing contacts in a thermostatically controlled device

21. - E5A01

What can cause the voltage across reactances in a series RLC circuit to be higher than the voltage applied to the entire circuit?

Select	Answer
A	Resistance
B	Conductance
C	Resonance
D	Capacitance

22. - E5B02

What letter is commonly used to represent susceptance?

Select	Answer
A	G
B	Y
C	X
D	B

23. - E5C07

Where is the impedance of a pure resistance plotted on rectangular coordinates?

Select	Answer
A	On a horizontal line, offset vertically above the horizontal axis
B	On the horizontal axis
C	On a line through the origin, slanted at 45 degrees
D	On the vertical axis

24. - E5D14

What is reactive power?

Select	Answer
A	Power consumed in wire resistance in an inductor
B	Power lost because of capacitor leakage
C	Wattless, nonproductive power
D	Power consumed in circuit Q

25. - E6A09

What is a depletion-mode FET?

Select	Answer
A	An FET that has no current flow between source and drain when no gate voltage is applied
B	An FET that exhibits a current flow between source and drain when no gate voltage is applied
C	Any FET without a channel
D	Any FET for which holes are the majority carriers

26. - E6B06

Which of the following is a common use of a Schottky diode?

Select	Answer
A	As a rectifier in high current power supplies
B	As a variable capacitance in an automatic frequency control circuit
C	As a VHF/UHF mixer or detector
D	As a constant voltage reference in a power supply

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 that utilize ternary math
D	Logic devices with 0, 1, and high-impedance output states

28. - E6D04

Which materials are commonly used as a core in an inductor?

Select	Answer
A	Ferrite and brass
B	Polystyrene and polyethylene
C	Cobalt and aluminum
D	Teflon and Delrin

29. - E6E09

Which of the following component package types would be most suitable for use at frequencies above the HF range?

Select	Answer
A	Radial lead
B	Axial lead
C	TO-220
D	Surface mount

30. - E6F05

Which describes an optical shaft encoder?

Select	Answer
A	A device that measures the strength of a beam of light using analog to digital conversion
B	A device that detects rotation of a control by interrupting a light source with a patterned wheel
C	A digital encryption device often used to encrypt spacecraft control signals
D	A device for generating RTTY signals by means of a rotating light source

31. - E7A03

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

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

32. - E7B02

What is a Class D amplifier?

Select	Answer
A	A frequency doubling amplifier
B	An amplifier that uses drift-mode FETs for high efficiency
C	A low power amplifier that uses a differential amplifier for improved linearity
D	A type of amplifier that uses switching technology to achieve high efficiency

33. - E7C08

Which of the following factors has the greatest effect on the bandwidth and response shape of a crystal ladder filter?

Select	Answer
A	The gain of the RF stage preceding the filter
B	The DC voltage applied to the quartz crystal
C	The relative frequencies of the individual crystals
D	The amplitude of the signals passing through the filter

34. - E7D11

What is the function of the pass transistor in a linear voltage regulator circuit?

Select	Answer
A	Maintains nearly constant output voltage over a wide range of load current
B	Permits a wide range of output voltage settings
C	Provides a stable input impedance over a wide range of source voltage
D	Maintains nearly constant output impedance over a wide range of load current

35. - E7E01

Which of the following can be used to generate FM phone emissions?

Select	Answer
A	A balanced modulator on the audio amplifier
B	A reactance modulator on the final amplifier
C	A balanced modulator on the oscillator
D	A reactance modulator on the oscillator

36. - E7F10

What aspect of receiver analog-to-digital conversion determines the maximum receive bandwidth of a Direct Digital Conversion SDR?

Select	Answer
A	Processor latency
B	Sample width in bits
C	Sample clock phase noise
D	Sample rate

37. - E7G05

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

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

38. - E7H08

Which of the following components can be used to reduce thermal drift in crystal oscillators?

Select	Answer
A	NP0 capacitors
B	Wirewound resistors
C	Toroidal inductors
D	Non-inductive resistors

39. - E8A04

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

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

40. - E8B10

What is frequency division multiplexing?

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

41. - E8C03

Why should phase-shifting of a PSK signal be done at the zero crossing of the RF signal?

Select	Answer
A	To minimize bandwidth
B	To improve carrier suppression
C	To simplify modulation
D	All these choices are correct

42. - E8D04

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

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

43. - E9A03

What is the radiation resistance of an antenna?

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

44. - E9B02

In the antenna radiation pattern shown in Figure E9-1, what is the front-to-back ratio?

Select	Answer
A	18 dB
B	14 dB
C	24 dB
D	36 dB

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

46. - E9D08

What happens as the Q of an antenna increases?

Select	Answer
A	Gain is reduced
B	SWR bandwidth decreases
C	More common-mode current is present on the feed line
D	SWR bandwidth increases

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 stub matching system
B	The omega matching system
C	The delta matching system
D	The gamma matching system

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

49. - E9G11

How are the wavelength scales on a Smith chart calibrated?

Select	Answer
A	In fractions of antenna electrical wavelength
B	In fractions of transmission line electrical frequency
C	In fractions of transmission line 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 allows DF antennas to receive signals at different vertical angles
C	It increases the sensitivity of a DF antenna array
D	It provides diversity reception that cancels multipath signals

Figure E9-1