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

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1. - E0A10

What toxic material may be present in some electronic components such as high voltage capacitors and transformers?

Select	Answer
A	Polychlorinated biphenyls
B	Polytetrafluoroethylene
C	Polyethylene
D	Polymorphic silicon

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	14.100 MHz
B	14.349 MHz
C	14.149 MHz
D	14.070 MHz

3. - E1B01

Which of the following constitutes a spurious emission?

Select	Answer
A	An amateur station transmission made without the proper call sign identification
B	An emission outside the signal's necessary bandwidth that can be reduced or eliminated without affecting the information transmitted
C	A signal transmitted to prevent its detection by any station other than the intended recipient
D	Any transmitted signal that unintentionally interferes with another licensed radio station

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	Business-related messages for non-profit organizations
C	All these choices are correct
D	Communications incidental to the purpose of the amateur service and remarks of a personal nature

5. - E1D12

Which of the following amateur stations may transmit one-way communications?

Select	Answer
A	A space station, beacon station, or telecommand station
B	A message forwarding station or automatically controlled digital station
C	All these choices are correct
D	A local repeater or linked repeater station

6. - E1E08

To which of the following examinees may a VE not administer an examination?

Select	Answer
A	Employees of the VE
B	Friends of the VE
C	All these choices are correct
D	Relatives of the VE as listed in the FCC rules

7. - E1F11

Which of the following best describes one of the standards that must be met by an external RF power amplifier if it is to qualify for a grant of FCC certification?

Select	Answer
A	It must produce full legal output when driven by not more than 5 watts of mean RF input power
B	It must be capable of external RF switching between its input and output networks
C	It must exhibit a gain of 0 dB or less over its full output range
D	It must satisfy the FCC's spurious emission standards when operated at the lesser of 1500 watts or its full output power

8. - E2A12

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

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

9. - E2B04

How is color information sent in analog SSTV?

Select	Answer
A	Color information is sent on a 2.8 kHz subcarrier
B	Color is sent in a color burst at the end of each line
C	Color lines are sent sequentially
D	Color is amplitude modulated on the frequency modulated intensity signal

10. - E2C10

Why might a DX station state that they are listening on another frequency?

Select	Answer
A	To improve operating efficiency by reducing interference
B	To separate the calling stations from the DX station
C	All these choices are correct
D	Because the DX station may be transmitting on a frequency that is prohibited to some responding stations

11. - E2D05

What is one advantage of the JT65 mode?

Select	Answer
A	Permits fast-scan TV transmissions over narrow bandwidth
B	The ability to decode signals which have a very low signal-to-noise ratio
C	Uses only a 65 Hz bandwidth
D	Easily copied by ear if necessary

12. - E2E02

What do the letters FEC mean as they relate to digital operation?

Select	Answer
A	First Error Correction
B	Final Error Correction
C	Forward Error Correction
D	Fatal Error Correction

13. - E3A04

What do Hepburn maps predict?

Select	Answer
A	Sporadic E propagation
B	Locations of auroral reflecting zones
C	Probability of tropospheric propagation
D	Likelihood of rain scatter along cold or warm fronts

14. - E3B03

What is the best time of day for transequatorial propagation?

Select	Answer
A	Afternoon or early evening
B	Morning
C	Noon
D	Late at night

15. - E3C07

Which of the following descriptors indicates the greatest solar flare intensity?

Select	Answer
A	Class M
B	Class A
C	Class X
D	Class B

16. - E4A04

How is the compensation of an oscilloscope probe typically adjusted?

Select	Answer
A	A high frequency sine wave is displayed and the probe is adjusted for maximum amplitude
B	A frequency standard is displayed and the probe is adjusted until the deflection time is accurate
C	A square wave is displayed and the probe is adjusted until the horizontal portions of the displayed wave are as nearly flat as possible
D	A DC voltage standard is displayed and the probe is adjusted until the displayed voltage is accurate

17. - E4B01

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

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

18. - E4C11

Why can an attenuator be used to reduce receiver overload on the lower frequency HF bands with little or no impact on signal-to-noise ratio?

Select	Answer
A	Atmospheric noise is generally greater than internally generated noise even after attenuation
B	The attenuator has a noise filter to suppress interference
C	The attenuator has a low-pass filter to increase the strength of lower frequency signals
D	Signals are attenuated separately from the noise

19. - E4D04

Which of the following may reduce or eliminate intermodulation interference in a repeater caused by another transmitter operating in close proximity?

Select	Answer
A	A band-pass filter in the feed line between the transmitter and receiver
B	A properly terminated circulator at the output of the repeater's transmitter
C	Utilizing a Class D final amplifier
D	Utilizing a Class C final amplifier

20. - E4E11

What could cause local AM broadcast band signals to combine to generate spurious signals in the MF or HF bands?

Select	Answer
A	You are receiving skywave signals from a distant station
B	Nearby corroded metal joints are mixing and re-radiating the broadcast signals
C	One or more of the broadcast stations is transmitting an over-modulated signal
D	Your station receiver IF amplifier stage is defective

21. - E5A09

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

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

22. - E5B01

What is the term for the time required for the capacitor in an RC circuit to be charged to 63.2% of the applied voltage or to discharge to 36.8% of its initial voltage?

Select	Answer
A	An exponential rate of one
B	A time factor of one
C	One time constant
D	One exponential period

23. - E5C01

Which of the following represents capacitive reactance in rectangular notation?

Select	Answer
A	+jX
B	Delta
C	Omega
D	-jX

24. - E5D08

How many watts are consumed in a circuit having a power factor of 0.6 if the input is 200VAC at 5 amperes?

Select	Answer
A	600 watts
B	1600 watts
C	1000 watts
D	200 watts

25. - E6A07

Which of the following indicates that a silicon NPN junction transistor is biased on?

Select	Answer
A	Base-to-emitter voltage of approximately 6 to 7 volts
B	Base-to-emitter resistance of approximately 0.6 to 0.7 ohms
C	Base-to-emitter resistance of approximately 6 to 7 ohms
D	Base-to-emitter voltage of approximately 0.6 to 0.7 volts

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

27. - E6C01

What is the function of hysteresis in a comparator?

Select	Answer
A	To increase the sensitivity
B	To prevent input noise from causing unstable output signals
C	To allow the comparator to be used with AC input signals
D	To cause the output to change states continually

28. - E6D12

What is inductor saturation?

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

29. - E6E08

How is power supplied to the most common type of MMIC?

Select	Answer
A	MMICs require no operating bias
B	Through a capacitor and RF choke connected to the amplifier input lead
C	Through a resistor and/or RF choke connected to the amplifier output lead
D	Directly to the bias voltage (VCC IN) lead

30. - E6F02

What happens to the conductivity of a photoconductive material when light shines on it?

Select	Answer
A	It increases
B	It decreases
C	It stays the same
D	It becomes unstable

31. - E7A05

Which of the following is a circuit that continuously alternates between two states without an external clock?

Select	Answer
A	T flip-flop
B	J-K flip-flop
C	Monostable multivibrator
D	Astable multivibrator

32. - E7B02

What is a Class D amplifier?

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

33. - E7C11

Which of the following describes a receiving filter's ability to reject signals occupying an adjacent channel?

Select	Answer
A	Shape factor
B	Noise factor
C	Passband ripple
D	Phase response

34. - E7D12

What is the dropout voltage of an analog voltage regulator?

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

35. - E7E11

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

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

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	4 bits
B	8 bits
C	10 bits
D	6 bits

37. - E7G03

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

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

38. - E7H10

What information is contained in the lookup table of a direct digital synthesizer (DDS)?

Select	Answer
A	The phase relationship between a voltage-controlled oscillator and the output waveform
B	The phase relationship between a reference oscillator and the output waveform
C	Amplitude values that represent the desired waveform
D	Frequently used receiver and transmitter frequencies

39. - E8A01

What is the name of the process that shows that a square wave is made up of a sine wave plus all its odd harmonics?

Select	Answer
A	Differential analysis
B	Fourier analysis
C	Vector analysis
D	Numerical analysis

40. - E8B11

What is digital time division multiplexing?

Select	Answer
A	Two or more signals are quadrature modulated to increase bandwidth efficiency
B	Two or more data streams share the same channel by transmitting time of transmission as the sub-carrier
C	Two or more data streams are assigned to discrete sub-carriers on an FM transmitter
D	Two or more signals are arranged to share discrete time slots of a data transmission

41. - E8C06

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

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

42. - E8D10

What are some of the differences between the Baudot digital code and ASCII?

Select	Answer
A	Baudot uses 5 data bits per character, ASCII uses 7 or 8; Baudot uses 2 characters as letters/figures shift codes, ASCII has no letters/figures shift code
B	Baudot uses 7 data bits per character, ASCII uses 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes
C	Baudot uses 4 data bits per character, ASCII uses 7 or 8; Baudot uses 1 character as a letters/figures shift code, ASCII has no letters/figures code
D	Baudot uses 6 data bits per character, ASCII uses 7 or 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes

43. - E9A13

What term describes station output, taking into account all gains and losses?

Select	Answer
A	Power factor
B	Effective radiated power
C	Apparent power
D	Half-power bandwidth

44. - E9B05

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

Select	Answer
A	Polarization
B	Azimuth
C	Elevation
D	Radiation resistance

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

46. - E9D06

What happens to the SWR bandwidth when one or more loading coils are used to resonate an electrically short antenna?

Select	Answer
A	It is unchanged if the loading coil is located at a voltage maximum point
B	It is unchanged if the loading coil is located at the feed point
C	It is decreased
D	It is increased

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	450 ohms
B	62 ohms
C	50 ohms
D	75 ohms

48. - E9F13

What impedance does a 1/4-wavelength transmission line present to a generator when the line is shorted at the far end?

Select	Answer
A	The same as the characteristic impedance of the transmission line
B	The same as the generator output impedance
C	Very low impedance
D	Very high impedance

49. - E9G03

Which of the following is often determined using a Smith chart?

Select	Answer
A	Satellite azimuth and elevation bearings
B	Trigonometric functions
C	Beam headings and radiation patterns
D	Impedance and SWR values in transmission lines

50. - E9H06

What is the triangulation method of direction finding?

Select	Answer
A	A fixed receiving station plots three headings to the signal source
B	A fixed receiving station uses three different antennas to plot the location of the signal source
C	Antenna headings from several different receiving locations are used to locate the signal source
D	The geometric angles of sky waves from the source are used to determine its position

Figure E9-2