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

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1. - E0A08

What does SAR measure?

Select	Answer
A	Synthetic Aperture Ratio of the human body
B	Signal Amplification Rating
C	The rate at which RF energy is absorbed by the body
D	The rate of RF energy reflected from stationary terrain

2. - E1A13

Who must be in physical control of the station apparatus of an amateur station aboard any vessel or craft that is documented or registered in the United States?

Select	Answer
A	Any person named in an amateur station license grant or a person holding an unrestricted Radiotelephone Operator Permit
B	Only a person named in an amateur station license grant
C	Only a person with an FCC Marine Radio license grant
D	Any person holding an FCC issued amateur license or who is authorized for alien reciprocal operation

3. - E1B08

What limitations may the FCC place on an amateur station if its signal causes interference to domestic broadcast reception, assuming that the receivers involved are of good engineering design?

Select	Answer
A	The amateur station must cease operation
B	The amateur station must avoid transmitting during certain hours on frequencies that cause the interference
C	The amateur station must cease operation on all frequencies below 30 MHz
D	The amateur station must cease operation on all frequencies above 30 MHz

4. - E1C04

What is meant by IARP?

Select	Answer
A	An indication of increased antenna reflected power
B	An international amateur radio permit that allows U.S. amateurs to operate in certain countries of the Americas
C	The internal amateur radio practices policy of the FCC
D	A forecast of intermittent aurora radio propagation

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	All these choices are correct
C	A local repeater or linked repeater station
D	A message forwarding station or automatically controlled digital station

6. - E1E05

What is the minimum passing score on all amateur operator license examinations?

Select	Answer
A	Minimum passing score of 70%
B	Minimum passing score of 77%
C	Minimum passing score of 74%
D	Minimum passing score of 80%

7. - E1F06

Under what circumstances might the FCC issue a Special Temporary Authority (STA) to an amateur station?

Select	Answer
A	To provide temporary operation while awaiting normal licensing
B	To provide for experimental amateur communications
C	To provide additional spectrum for personal use
D	To allow regular operation on Land Mobile channels

8. - E2A06

What are Keplerian elements?

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

9. - E2B12

What signals SSTV receiving software to begin a new picture line?

Select	Answer
A	A two-tone signal
B	Specific tone frequencies
C	Elapsed time
D	Specific tone amplitudes

10. - E2C12

What technique do individual nodes use to form a mesh network?

Select	Answer
A	Acting as store-and-forward digipeaters
B	Custom code plugs for the local trunking systems
C	Forward error correction and Viterbi codes
D	Discovery and link establishment protocols

11. - E2D07

What digital protocol is used by APRS?

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

12. - E2E06

What is the most common data rate used for HF packet?

Select	Answer
A	1200 baud
B	48 baud
C	110 baud
D	300 baud

13. - E3A05

Tropospheric propagation of microwave signals often occurs in association with what phenomenon?

Select	Answer
A	Grayline
B	Lightning discharges
C	Warm and cold fronts
D	Sprites and jets

14. - E3B09

At what time of year is sporadic E propagation most likely to occur?

Select	Answer
A	Around the equinoxes, especially the spring equinox
B	Around the solstices, especially the summer solstice
C	Around the solstices, especially the winter solstice
D	Around the equinoxes, especially the fall equinox

15. - E3C05

What orientation of Bz (B sub z) increases the likelihood that incoming particles from the sun will cause disturbed conditions?

Select	Answer
A	Southward
B	Eastward
C	Northward
D	Westward

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 spectrum analyzer
C	A wattmeter
D	A time-domain reflectometer

17. - E4B03

Which S parameter is equivalent to forward gain?

Select	Answer
A	S21
B	S11
C	S12
D	S22

18. - E4C10

What is an advantage of having a variety of receiver IF bandwidths from which to select?

Select	Answer
A	Multiple frequencies can be received simultaneously if desired
B	The noise figure of the RF amplifier can be adjusted to match the modulation type, thus increasing receiver sensitivity
C	Receive bandwidth can be set to match the modulation bandwidth, maximizing signal-to-noise ratio and minimizing interference
D	Receiver power consumption can be reduced when wider bandwidth is not required

19. - E4D05

What transmitter frequencies would cause an intermodulation-product signal in a receiver tuned to 146.70 MHz when a nearby station transmits on 146.52 MHz?

Select	Answer
A	146.34 MHz and 146.61 MHz
B	173.35 MHz and 139.40 MHz
C	146.88 MHz and 146.34 MHz
D	146.10 MHz and 147.30 MHz

20. - E4E03

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

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

21. - E5A02

What is resonance in an LC or RLC circuit?

Select	Answer
A	The highest frequency that will pass current
B	The lowest frequency that will pass current
C	The frequency at which the capacitive reactance equals the inductive reactance
D	The frequency at which the reactive impedance equals the resistive impedance

22. - E5B07

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 500 ohms, R is 1 kilohm, and XL is 250 ohms?

Select	Answer
A	14.0 degrees with the voltage leading the current
B	14.0 degrees with the voltage lagging the current
C	68.2 degrees with the voltage leading the current
D	68.2 degrees with the voltage lagging the current

23. - E5C01

Which of the following represents capacitive reactance in rectangular notation?

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

24. - E5D09

What happens to reactive power in an AC circuit that has both ideal inductors and ideal capacitors?

Select	Answer
A	It is dissipated in the formation of inductive and capacitive fields
B	It is repeatedly exchanged between the associated magnetic and electric fields, but is not dissipated
C	It is dissipated as kinetic energy in the circuit
D	It is dissipated as heat in the circuit

25. - E6A01

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

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

26. - E6B11

What is used to control the attenuation of RF signals by a PIN diode?

Select	Answer
A	Forward DC bias current
B	A sub-harmonic pump signal
C	Reverse voltage larger than the RF signal
D	Capacitance of an RF coupling capacitor

27. - E6C10

In Figure E6-3, what is the schematic symbol for a NOR gate?

Select	Answer
A	1
B	2
C	4
D	3

28. - E6D12

What is inductor saturation?

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

29. - E6E06

What characteristics of the MMIC make it a popular choice for VHF through microwave circuits?

Select	Answer
A	Nearly infinite gain, very high input impedance, and very low output impedance
B	The ability to retrieve information from a single signal even in the presence of other strong signals
C	Controlled gain, low noise figure, and constant input and output impedance over the specified frequency range
D	Plate current that is controlled by a control grid

30. - E6F09

What is the efficiency of a photovoltaic cell?

Select	Answer
A	The relative fraction of light that is converted to current
B	The open-circuit voltage divided by the short-circuit current under full illumination
C	Cost per kilowatt-hour generated
D	The output RF power divided by the input DC power

31. - E7A11

What type of logic defines "1" as a high voltage?

Select	Answer
A	Negative logic
B	Positive Logic
C	Assertive Logic
D	Reverse Logic

32. - E7B13

Which of the following describes an emitter follower (or common collector) amplifier?

Select	Answer
A	A differential amplifier with both inputs fed to the emitter of the input transistor
B	An amplifier with a low impedance output that follows the base input voltage
C	A two-transistor amplifier with the emitters sharing a common bias resistor
D	An OR circuit with only one emitter used for output

33. - E7C03

What advantage does a series-L Pi-L-network have over a series-L Pi-network for impedance matching between the final amplifier of a vacuum-tube transmitter and an antenna?

Select	Answer
A	Greater transformation range
B	Does not require a capacitor
C	Greater harmonic suppression
D	Higher efficiency

34. - E7D05

Which of the following types of linear voltage regulator places a constant load on the unregulated voltage source?

Select	Answer
A	A series regulator
B	A constant current source
C	A shunt current source
D	A shunt regulator

35. - E7E08

What are the principal frequencies that appear at the output of a mixer circuit?

Select	Answer
A	1.414 and 0.707 times the input frequency
B	The square root of the product of input frequencies
C	The two input frequencies along with their sum and difference frequencies
D	Two and four times the original frequency

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	FIR filters are easier to implement for a given set of passband rolloff requirements
B	All these choices are correct
C	FIR filters can delay all frequency components of the signal by the same amount
D	FIR filters can respond faster to impulses

37. - E7G04

What is meant by the "op-amp input offset voltage"?

Select	Answer
A	The differential input voltage needed to bring the open loop output voltage to zero
B	The potential between the amplifier input terminals of the op-amp in an open loop condition
C	The output voltage of the op-amp minus its input voltage
D	The difference between the output voltage of the op-amp and the input voltage required in the immediately following stage

38. - E7H02

What is a microphonic?

Select	Answer
A	Distortion caused by RF pickup on the microphone cable
B	Changes in oscillator frequency due to mechanical vibration
C	An IC used for amplifying microphone signals
D	Excess loading of the microphone by an oscillator

39. - E8A09

How many different input levels can be encoded by an analog-to-digital converter with 8-bit resolution?

Select	Answer
A	256 divided by the gain of the input amplifier
B	256
C	8 multiplied by the gain of the input amplifier
D	8

40. - E8B07

Orthogonal Frequency Division Multiplexing is a technique used for which type of amateur communication?

Select	Answer
A	High-speed digital modes
B	EME
C	Extremely low-power contacts
D	OFDM signals are not allowed on amateur bands

41. - E8C03

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

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

42. - E8D03

How does the spread spectrum technique of frequency hopping work?

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

43. - E9A05

What is included in the total resistance of an antenna system?

Select	Answer
A	Radiation resistance plus loss resistance
B	Radiation resistance plus transmission resistance
C	Radiation resistance plus space impedance
D	Transmission-line resistance plus radiation resistance

44. - E9B04

What is the front-to-back ratio of the radiation pattern shown in Figure E92?

Select	Answer
A	15 dB
B	3 dB
C	28 dB
D	38 dB

45. - E9C04

What happens to the radiation pattern of an unterminated long wire antenna as the wire length is increased?

Select	Answer
A	The lobes align more in the direction of the wire
B	The lobes become more perpendicular to the wire
C	The vertical angle increases
D	The front-to-back ratio decreases

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

47. - E9E09

Which of the following is used to shunt-feed a grounded tower at its base?

Select	Answer
A	All these choices are correct
B	Hairpin match
C	Gamma match
D	Double-bazooka match

48. - E9F03

Why is the physical length of a coaxial cable transmission line shorter than its electrical length?

Select	Answer
A	Skin effect is less pronounced in the coaxial cable
B	Electrical signals move more slowly in a coaxial cable than in air
C	The characteristic impedance is higher in a parallel feed line
D	The surge impedance is higher in a parallel feed line

49. - E9G07

On the Smith chart shown in Figure E9-3, what is the only straight line shown?

Select	Answer
A	The reactance axis
B	The voltage axis
C	The resistance axis
D	The current axis

50. - E9H02

Which is generally true for low band (160 meter and 80 meter) receiving antennas?

Select	Answer
A	All these choices are correct
B	They must be erected at least 1/2 wavelength above the ground to attain good directivity
C	Atmospheric noise is so high that gain over a dipole is not important
D	Low loss coax transmission line is essential for good performance

Figure E6-3

Figure E9-3