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

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1. - E0A02

When evaluating RF exposure levels from your station at a neighbor's home, what must you do?

Select	Answer
A	Ensure signals from your station are less than the controlled Maximum Permitted Emission (MPE) limits
B	Ensure signals from your station are less than the uncontrolled Maximum Permitted Emission (MPE) limits
C	Ensure signals from your station are less than the uncontrolled Maximum Permitted Exposure (MPE) limits
D	Ensure signals from your station are less than the controlled Maximum Permitted Exposure (MPE) limits

2. - E1A08

If a station in a message forwarding system inadvertently forwards a message that is in violation of FCC rules, who is primarily accountable for the rules violation?

Select	Answer
A	The control operator of the packet bulletin board station
B	The control operators of all the stations in the system not authenticating the source from which they accept communications
C	The control operator of the originating station
D	The control operators of all the stations in the system

3. - E1B03

Within what distance must an amateur station protect an FCC monitoring facility from harmful interference?

Select	Answer
A	10 miles
B	3 miles
C	30 miles
D	1 mile

4. - E1C14

How long must an operator wait after filing a notification with the Utilities Technology Council (UTC) before operating on the 2200 meter or 630 meter band?

Select	Answer
A	Operators may operate after 30 days, providing they have not been told that their station is within 1 km of PLC systems using those frequencies
B	Operators must not operate until approval is received
C	Operators may not operate until a test signal has been transmitted in coordination with the local power company
D	Operations may commence immediately, and may continue unless interference is reported by the UTC

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	Data containing personal information
C	Telecommand signals from a space telecommand station
D	Binary control characters

6. - E1E12

What must the VE team do with the application form if the examinee does not pass the exam?

Select	Answer
A	Return the application document to the examinee
B	Maintain the application form with the VEC's records
C	Destroy the application form
D	Send the application form to the FCC and inform the FCC of the grade

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

8. - E2A09

What do the terms L band and S band specify regarding satellite communications?

Select	Answer
A	FM and Digital Store-and-Forward systems
B	The 2 meter and 70 centimeter bands
C	The 23 centimeter and 13 centimeter bands
D	Which sideband to use

9. - E2B05

Which of the following describes the use of vestigial sideband in analog fast-scan TV transmissions?

Select	Answer
A	Vestigial sideband reduces bandwidth while allowing for simple video detector circuitry
B	The vestigial sideband carries the audio information
C	Vestigial sideband provides high frequency emphasis to sharpen the picture
D	The vestigial sideband contains chroma information

10. - E2C07

What is the Cabrillo format?

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

11. - E2D07

What digital protocol is used by APRS?

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

12. - E2E06

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

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

13. - E3A14

What is meant by circularly polarized electromagnetic waves?

Select	Answer
A	Waves produced by a loop antenna
B	Waves that circle the Earth
C	Waves with an electric field bent into a circular shape
D	Waves with a rotating electric field

14. - E3B02

What is the approximate maximum range for signals using transequatorial propagation?

Select	Answer
A	2500 miles
B	1000 miles
C	7500 miles
D	5000 miles

15. - E3C11

What does VOACAP software model?

Select	Answer
A	AC voltage and impedance
B	HF propagation
C	AC current and impedance
D	VHF radio propagation

16. - E4A05

What is the purpose of the prescaler function on a frequency counter?

Select	Answer
A	It prevents oscillation in a low-frequency counter circuit
B	It divides a higher frequency signal so a low-frequency counter can display the input frequency
C	It amplifies low-level signals for more accurate counting
D	It multiplies a higher frequency signal so a low-frequency counter can display the operating frequency

17. - E4B03

Which S parameter is equivalent to forward gain?

Select	Answer
A	S12
B	S11
C	S22
D	S21

18. - E4C04

What is the noise figure of a receiver?

Select	Answer
A	The ratio of thermal noise to atmospheric noise
B	The ratio of atmospheric noise to phase noise
C	The ratio of the noise bandwidth in hertz to the theoretical bandwidth of a resistive network
D	The ratio in dB of the noise generated by the receiver to the theoretical minimum noise

19. - E4D08

What causes intermodulation in an electronic circuit?

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

20. - E4E07

Which of the following can cause shielded cables to radiate or receive interference?

Select	Answer
A	Common-mode currents on the shield and conductors
B	Use of braided shielding material
C	Low inductance ground connections at both ends of the shield
D	Tying all ground connections to a common point resulting in differential-mode currents in the shield

21. - E5A10

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

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

22. - E5B03

How is impedance in polar form converted to an equivalent admittance?

Select	Answer
A	Square the magnitude and subtract 90 degrees from the angle
B	Take the reciprocal of the angle and change the sign of the magnitude
C	Take the reciprocal of the magnitude and change the sign of the angle
D	Take the square root of the magnitude and add 180 degrees to the angle

23. - E5C04

What coordinate system is often used to display the resistive, inductive, and/or capacitive reactance components of impedance?

Select	Answer
A	Elliptical coordinates
B	Faraday grid
C	Rectangular coordinates
D	Maidenhead grid

24. - E5D10

How can the true power be determined in an AC circuit where the voltage and current are out of phase?

Select	Answer
A	By dividing the apparent power by the power factor
B	By dividing the reactive power by the power factor
C	By multiplying the reactive power by the power factor
D	By multiplying the apparent power by the power factor

25. - E6A08

What term indicates the frequency at which the grounded-base current gain of a transistor has decreased to 0.7 of the gain obtainable at 1 kHz?

Select	Answer
A	Alpha cutoff frequency
B	Corner frequency
C	Beta cutoff frequency
D	Alpha rejection frequency

26. - E6B05

What characteristic of a PIN diode makes it useful as an RF switch?

Select	Answer
A	Reverse bias controls its forward voltage drop
B	Extremely high reverse breakdown voltage
C	Low junction capacitance
D	Ability to dissipate large amounts of power

27. - E6C08

In Figure E6-3, what is the schematic symbol for a NAND gate?

Select	Answer
A	1
B	3
C	4
D	2

28. - E6D12

What is inductor saturation?

Select	Answer
A	The inductor's voltage rating is exceeded causing a flashover
B	Adjacent inductors become over-coupled
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	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. - E6F10

What is the most common type of photovoltaic cell used for electrical power generation?

Select	Answer
A	Copper oxide
B	Cadmium Sulfide
C	Selenium
D	Silicon

31. - E7A01

Which circuit is bistable?

Select	Answer
A	A bipolar amplifier
B	An AND gate
C	A flip-flop
D	An OR gate

32. - E7B18

What is a characteristic of a grounded-grid amplifier?

Select	Answer
A	High power gain
B	Low input impedance
C	High filament voltage
D	Low bandwidth

33. - E7C02

Which of the following is a property of a T-network with series capacitors and a parallel shunt inductor?

Select	Answer
A	It is a band-pass filter
B	It is a notch filter
C	It is a high-pass filter
D	It is a low-pass filter

34. - E7D09

What is the main reason to use a charge controller with a solar power system?

Select	Answer
A	Matching of day and night charge rates
B	Control of electrolyte levels during battery discharge
C	Prevention of battery damage due to overcharge
D	Prevention of battery undercharge

35. - E7E07

What is meant by the term "baseband" in radio communications?

Select	Answer
A	The unmodulated bandwidth of the transmitted signal
B	The basic oscillator frequency in an FM transmitter that is multiplied to increase the deviation and carrier frequency
C	The frequency range occupied by a message signal prior to modulation
D	The lowest frequency band that the transmitter or receiver covers

36. - E7F10

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

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

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 increases linearly with increasing frequency
D	It does not vary with frequency

38. - E7H07

How can an oscillator's microphonic responses be reduced?

Select	Answer
A	Mechanically isolate the oscillator circuitry from its enclosure
B	Reduce noise on the oscillator's power supply
C	Use NP0 capacitors
D	Increase the bias voltage

39. - E8A05

What of the following instruments would be the most accurate for measuring the RMS voltage of a complex waveform?

Select	Answer
A	A D'Arsonval meter
B	An absorption wave meter
C	A grid dip meter
D	A true-RMS calculating meter

40. - E8B08

What describes Orthogonal Frequency Division Multiplexing?

Select	Answer
A	A digital mode for narrow-band, slow-speed transmissions
B	A digital modulation technique using subcarriers at frequencies chosen to avoid intersymbol interference
C	A frequency modulation technique that uses non-harmonically related frequencies
D	A bandwidth compression technique using Fourier transforms

41. - E8C10

How may data rate be increased without increasing bandwidth?

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

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 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
C	Baudot uses 7 data bits per character, ASCII uses 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes
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. - 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	317 watts
B	126 watts
C	2000 watts
D	300 watts

44. - E9B10

What is the principle of a Method of Moments analysis?

Select	Answer
A	A wire is modeled as a series of segments, each having a uniform value of current
B	A wire is modeled as a single sine-wave voltage source
C	A wire is modeled as a series of segments, each having a distinct value of voltage across it
D	A wire is modeled as a single sine-wave current generator

45. - E9C06

What is the effect of adding a terminating resistor to a rhombic antenna?

Select	Answer
A	It decreases the ground loss
B	It reflects the standing waves on the antenna elements back to the transmitter
C	It changes the radiation pattern from horizontal to vertical polarization
D	It changes the radiation pattern from bidirectional to unidirectional

46. - E9D05

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

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

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	Gamma match
C	Hairpin match
D	Double-bazooka match

48. - E9F04

What impedance does a 1/2-wavelength transmission line present to a generator when the line is shorted at the far end?

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

49. - E9G02

What type of coordinate system is used in a Smith chart?

Select	Answer
A	Resistance lines and reactance chords
B	Voltage lines and current chords
C	Voltage circles and current arcs
D	Resistance circles and reactance arcs

50. - E9H05

What is the main drawback of a small wire-loop antenna for direction finding?

Select	Answer
A	All these choices are correct
B	It has a bidirectional pattern
C	It is practical for use only on VHF and higher bands
D	It has no clearly defined null

Figure E6-3