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

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1. - E0A08

What does SAR measure?

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

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

3. - E1B05

What is the National Radio Quiet Zone?

Select	Answer
A	An area in New Mexico surrounding the White Sands Test Area
B	An area in Puerto Rico surrounding the Arecibo Radio Telescope
C	An area surrounding the National Radio Astronomy Observatory
D	An area in Florida surrounding Cape Canaveral

4. - E1C08

What is the maximum permissible duration of a remotely controlled station's transmissions if its control link malfunctions?

Select	Answer
A	5 minutes
B	30 seconds
C	3 minutes
D	10 minutes

5. - E1D02

Which of the following may transmit special codes intended to obscure the meaning of messages?

Select	Answer
A	Auxiliary relay links carrying repeater audio
B	Telecommand signals from a space telecommand station
C	Binary control characters
D	Data containing personal information

6. - E1E10

What must the administering VEs do after the administration of a successful examination for an amateur operator license?

Select	Answer
A	They must collect and send the documents to the NCVEC for grading
B	They must submit the application document to the coordinating VEC according to the coordinating VEC instructions
C	They must collect and submit the documents to the coordinating VEC for grading
D	They must collect and send the documents to the FCC according to instructions

7. - E1F02

What privileges are authorized in the U.S. to persons holding an amateur service license granted by the government of Canada?

Select	Answer
A	All privileges of the Amateur Extra Class license
B	None, they must obtain a U.S. license
C	Full privileges, up to and including those of the Amateur Extra Class license, on the 80, 40, 20, 15, and 10 meter bands
D	The operating terms and conditions of the Canadian amateur service license, not to exceed U.S. Amateur Extra Class license privileges

8. - E2A12

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

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

9. - E2B09

What hardware, other than a receiver with SSB capability and a suitable computer, is needed to decode SSTV using Digital Radio Mondiale (DRM)?

Select	Answer
A	A special notch filter to remove synchronization pulses
B	A special IF converter
C	A special front end limiter
D	No other hardware is needed

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. - E2D02

Which of the following is a good technique for making meteor scatter contacts?

Select	Answer
A	Short transmissions with rapidly repeated call signs and signal reports
B	Use of special digital modes
C	All these choices are correct
D	15-second timed transmission sequences with stations alternating based on location

12. - E2E13

Which of these digital modes has the fastest data throughput under clear communication conditions?

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

13. - E3A08

When a meteor strikes the Earth's atmosphere, a cylindrical region of free electrons is formed at what layer of the ionosphere?

Select	Answer
A	The F2 layer
B	The F1 layer
C	The E layer
D	The D layer

14. - E3B11

At what time of day can sporadic E propagation occur?

Select	Answer
A	Only around sunset and sunrise
B	Only in hours of darkness
C	Any time
D	Only around sunset

15. - E3C15

What might be indicated by a sudden rise in radio background noise across a large portion of the HF spectrum?

Select	Answer
A	Long-path propagation is likely
B	Increased transequatorial propagation is likely
C	A temperature inversion has occurred
D	A solar flare has occurred

16. - E4A09

Which of the following is good practice when using an oscilloscope probe?

Select	Answer
A	Keep the signal ground connection of the probe as short as possible
B	Never use a DC-coupled probe to measure an AC circuit
C	All these choices are correct
D	Never use a high-impedance probe to measure a low-impedance circuit

17. - E4B06

How much power is being absorbed by the load when a directional power meter connected between a transmitter and a terminating load reads 100 watts forward power and 25 watts reflected power?

Select	Answer
A	100 watts
B	125 watts
C	75 watts
D	25 watts

18. - E4C02

Which of the following receiver circuits can be effective in eliminating interference from strong out-of-band signals?

Select	Answer
A	A narrow IF filter
B	A notch filter
C	A properly adjusted product detector
D	A front-end filter or pre-selector

19. - E4D08

What causes intermodulation in an electronic circuit?

Select	Answer
A	Too little gain
B	Positive feedback
C	Lack of neutralization
D	Nonlinear circuits or devices

20. - E4E02

Which of the following types of noise can often be reduced with a digital signal processing noise filter?

Select	Answer
A	Broadband white noise
B	Power line noise
C	Ignition noise
D	All these choices are correct

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	Conductance
B	Resistance
C	Resonance
D	Capacitance

22. - E5B09

What is the relationship between the AC current through a capacitor and the voltage across a capacitor?

Select	Answer
A	Voltage and current are in phase
B	Current leads voltage by 90 degrees
C	Voltage and current are 180 degrees out of phase
D	Voltage leads current by 90 degrees

23. - E5C06

What does the impedance 50-j25 represent?

Select	Answer
A	25 ohms resistance in series with 50 ohms capacitive reactance
B	25 ohms resistance in series with 50 ohms inductive reactance
C	50 ohms resistance in series with 25 ohms capacitive reactance
D	50 ohms resistance in series with 25 ohms inductive reactance

24. - E5D14

What is reactive power?

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

25. - E6A06

What is the beta of a bipolar junction transistor?

Select	Answer
A	The change in collector current with respect to base current
B	The breakdown voltage of the base to collector junction
C	The switching speed
D	The frequency at which the current gain is reduced to 0.707

26. - E6B02

What is an important characteristic of a Schottky diode as compared to an ordinary silicon diode when used as a power supply rectifier?

Select	Answer
A	Much higher reverse voltage breakdown
B	More constant reverse avalanche voltage
C	Less forward voltage drop
D	Longer carrier retention time

27. - E6C01

What is the function of hysteresis in a comparator?

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

28. - E6D09

What devices are commonly used as VHF and UHF parasitic suppressors at the input and output terminals of a transistor HF amplifier?

Select	Answer
A	Steel-core toroids
B	Butterworth filters
C	Electrolytic capacitors
D	Ferrite beads

29. - E6E06

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

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

30. - E6F01

What absorbs the energy from light falling on a photovoltaic cell?

Select	Answer
A	Holes
B	Photons
C	Protons
D	Electrons

31. - E7A09

What logical operation is performed by an exclusive NOR gate?

Select	Answer
A	It produces logic 0 at its output if only one input is logic 1
B	It produces logic 1 at its output if only one input is logic 1
C	It produces logic 0 at its output only if all inputs are logic 0
D	It produces logic 1 at its output only if all inputs are logic 1

32. - E7B16

What is the effect of intermodulation products in a linear power amplifier?

Select	Answer
A	Low efficiency
B	All these choices are correct
C	Creation of parasitic oscillations
D	Transmission of spurious signals

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

34. - E7D04

Which of the following types of linear voltage regulator usually make the most efficient use of the primary power source?

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

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. - E7F01

What is meant by direct digital conversion as applied to software defined radios?

Select	Answer
A	Incoming RF is digitized by an analog-to-digital converter without being mixed with a local oscillator signal
B	Software is converted from source code to object code during operation of the receiver
C	A switching mixer is used to generate I and Q signals directly from the RF input
D	Incoming RF is converted to a control voltage for a voltage controlled oscillator

37. - E7G08

How does the gain of an ideal operational amplifier vary with frequency?

Select	Answer
A	It decreases linearly with increasing frequency
B	It decreases logarithmically with increasing frequency
C	It does not vary with frequency
D	It increases linearly with increasing frequency

38. - E7H05

How is positive feedback supplied in a Pierce oscillator?

Select	Answer
A	Through a tapped coil
B	Through a neutralizing capacitor
C	Through link coupling
D	Through a quartz crystal

39. - E8A10

What is the purpose of a low-pass filter used in conjunction with a digital-to-analog converter?

Select	Answer
A	Lower the input bandwidth to increase the effective resolution
B	All these choices are correct
C	Remove harmonics from the output caused by the discrete analog levels generated
D	Improve accuracy by removing out-of-sequence codes from the input

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	1.67
B	60
C	0.6
D	0.167

41. - E8C02

What is the definition of symbol rate in a digital transmission?

Select	Answer
A	The number of characters carried per second by the station-to-station link
B	The number of control characters in a message packet
C	The duration of each bit in a message sent over the air
D	The rate at which the waveform changes to convey information

42. - E8D10

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

Select	Answer
A	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
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 6 data bits per character, ASCII uses 7 or 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes
D	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

43. - E9A06

What is the effective radiated power relative to a dipole of a repeater station with 200 watts transmitter power output, 4 dB feed line loss, 3.2 dB duplexer loss, 0.8 dB circulator loss, and 10 dBd antenna gain?

Select	Answer
A	2000 watts
B	126 watts
C	317 watts
D	300 watts

44. - E9B06

What is the elevation angle of peak response in the antenna radiation pattern shown in Figure E9-2?

Select	Answer
A	7.5 degrees
B	75 degrees
C	25 degrees
D	45 degrees

45. - E9C11

How is the far-field elevation pattern of a vertically polarized antenna affected by being mounted over seawater versus soil?

Select	Answer
A	Fewer vertical angle lobes will be present
B	Additional higher vertical angle lobes will appear
C	The low-angle radiation increases
D	The low-angle radiation decreases

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 front-to-back ratio increases
D	The SWR is reduced

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	75 ohms
B	450 ohms
C	62 ohms
D	50 ohms

48. - E9F12

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

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

49. - E9G11

How are the wavelength scales on a Smith chart calibrated?

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

50. - E9H11

What feature of a cardioid pattern antenna makes it useful for direction finding?

Select	Answer
A	A very sharp peak
B	A very sharp single null
C	Broadband response
D	High radiation angle

Figure E9-2