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

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1. - E0A08

What does SAR measure?

SelectAnswer
ASynthetic Aperture Ratio of the human body
BThe rate of RF energy reflected from stationary terrain
CThe rate at which RF energy is absorbed by the body
DSignal Amplification Rating

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?

SelectAnswer
AThe control operators of all the stations in the system
BThe control operators of all the stations in the system not authenticating the source from which they accept communications
CThe control operator of the packet bulletin board station
DThe control operator of the originating station

3. - E1B04

What must be done before placing an amateur station within an officially designated wilderness area or wildlife preserve, or an area listed in the National Register of Historic Places?

SelectAnswer
AA form FSD-15 must be submitted to the Department of the Interior
BA proposal must be submitted to the National Park Service
CAn Environmental Assessment must be submitted to the FCC
DA letter of intent must be filed with the Environmental Protection Agency

4. - E1C02

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

SelectAnswer
ABusiness-related messages for non-profit organizations
BAll these choices are correct
CMessages intended for users of the maritime satellite service
DCommunications incidental to the purpose of the amateur service and remarks of a personal nature

5. - E1D08

Which VHF amateur bands have frequencies authorized for space stations?

SelectAnswer
A2 meters and 1.25 meters
B6 meters and 2 meters
C2 meters
D6 meters, 2 meters, and 1.25 meters

6. - E1E09

What may be the penalty for a VE who fraudulently administers or certifies an examination?

SelectAnswer
ARevocation of the VE's amateur station license grant and the suspension of the VE's amateur operator license grant
BAll these choices are correct
CA sentence of up to one year in prison
DA fine of up to $1000 per occurrence

7. - E1F04

Which of the following geographic descriptions approximately describes "Line A"?

SelectAnswer
AA line roughly parallel to and north of the border between the U.S. and Mexico
BA line roughly parallel to and west of the U.S. Atlantic coastline
CA line roughly parallel to and east of the U.S. Pacific coastline
DA line roughly parallel to and south of the border between the U.S. and Canada

8. - E2A13

Which of the following techniques is normally used by low Earth orbiting digital satellites to relay messages around the world?

SelectAnswer
ANode hopping
BMulti-satellite relaying
CStore-and-forward
DDigipeating

9. - E2B04

How is color information sent in analog SSTV?

SelectAnswer
AColor is amplitude modulated on the frequency modulated intensity signal
BColor lines are sent sequentially
CColor information is sent on a 2.8 kHz subcarrier
DColor is sent in a color burst at the end of each line

10. - E2C01

What indicator is required to be used by U.S.-licensed operators when operating a station via remote control and the remote transmitter is located in the U.S.?

SelectAnswer
A/R# where # is the district of the remote station
B/ followed by the ARRL Section of the remote station
CNo additional indicator is required
D/ followed by the USPS two-letter abbreviation for the state in which the remote station is located

11. - E2D01

Which of the following digital modes is designed for meteor scatter communications?

SelectAnswer
AAPRS
BWSPR
CMSK144
DHellschreiber

12. - E2E06

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

SelectAnswer
A300 baud
B48 baud
C110 baud
D1200 baud

13. - E3A07

Atmospheric ducts capable of propagating microwave signals often form over what geographic feature?

SelectAnswer
AForests
BMountain ranges
CUrban areas
DBodies of water

14. - E3B04

What is meant by the terms "extraordinary" and "ordinary" waves?

SelectAnswer
ARefracted rays and reflected waves
BExtraordinary waves describe rare long-skip propagation compared to ordinary waves, which travel shorter distances
CIndependent waves created in the ionosphere that are elliptically polarized
DLong-path and short-path waves

15. - E3C11

What does VOACAP software model?

SelectAnswer
AAC current and impedance
BHF propagation
CAC voltage and impedance
DVHF radio propagation

16. - E4A02

Which of the following parameters does a spectrum analyzer display on the vertical and horizontal axes?

SelectAnswer
ASWR and frequency
BRF amplitude and time
CSWR and time
DRF amplitude and frequency

17. - E4B11

Which of the following can be measured with a vector network analyzer?

SelectAnswer
AInput impedance
BReflection coefficient
CAll these choices are correct
DOutput impedance

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?

SelectAnswer
ASignals are attenuated separately from the noise
BThe attenuator has a noise filter to suppress interference
CThe attenuator has a low-pass filter to increase the strength of lower frequency signals
DAtmospheric noise is generally greater than internally generated noise even after attenuation

19. - E4D11

Why are odd-order intermodulation products, created within a receiver, of particular interest compared to other products?

SelectAnswer
AOdd-order intermodulation produces three products for every input signal within the band of interest
BOdd-order products of two signals in the band of interest are also likely to be within the band
COdd-order products overload the IF filters
DOdd-order products are an indication of poor image rejection

20. - E4E04

How can conducted and radiated noise caused by an automobile alternator be suppressed?

SelectAnswer
ABy installing filter capacitors in series with the DC power lead and a blocking capacitor in the field lead
BBy installing a noise suppression resistor and a blocking capacitor in both leads
CBy installing a high-pass filter in series with the radio's power lead and a low-pass filter in parallel with the field lead
DBy connecting the radio's power leads directly to the battery and by installing coaxial capacitors in line with the alternator leads

21. - E5A05

What is the result of increasing the Q of an impedance-matching circuit?

SelectAnswer
AIt has no effect on impedance matching
BMatching range is increased
CMatching bandwidth is increased
DMatching bandwidth is decreased

22. - E5B08

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 100 ohms, R is 100 ohms, and XL is 75 ohms?

SelectAnswer
A14 degrees with the voltage lagging the current
B14 degrees with the voltage leading the current
C76 degrees with the voltage leading the current
D76 degrees with the voltage lagging the current

23. - E5C07

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

SelectAnswer
AOn the vertical axis
BOn a line through the origin, slanted at 45 degrees
COn a horizontal line, offset vertically above the horizontal axis
DOn the horizontal axis

24. - E5D05

What is the power factor of an RL circuit having a 30-degree phase angle between the voltage and the current?

SelectAnswer
A1.73
B0.5
C0.577
D0.866

25. - E6A06

What is the beta of a bipolar junction transistor?

SelectAnswer
AThe frequency at which the current gain is reduced to 0.707
BThe switching speed
CThe breakdown voltage of the base to collector junction
DThe change in collector current with respect to base current

26. - E6B07

What is the failure mechanism when a junction diode fails due to excessive current?

SelectAnswer
AExcessive junction temperature
BInsufficient forward voltage
CExcessive inverse voltage
DCharge carrier depletion

27. - E6C03

What is tri-state logic?

SelectAnswer
ALogic devices with 0, 1, and high-impedance output states
BLow-power logic devices designed to operate at 3 volts
CLogic devices that utilize ternary math
DProprietary logic devices manufactured by Tri-State Devices

28. - E6D13

What is the primary cause of inductor self-resonance?

SelectAnswer
AThe skin effect
BNon-linear core hysteresis
CInter-turn capacitance
DInductive kickback

29. - E6E05

Which of the following noise figure values is typical of a low-noise UHF preamplifier?

SelectAnswer
A2 dB
B44 dBm
C-10 dB
D-20 dBm

30. - E6F02

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

SelectAnswer
AIt stays the same
BIt increases
CIt decreases
DIt becomes unstable

31. - E7A09

What logical operation is performed by an exclusive NOR gate?

SelectAnswer
AIt produces logic 1 at its output if only one input is logic 1
BIt produces logic 0 at its output only if all inputs are logic 0
CIt produces logic 1 at its output only if all inputs are logic 1
DIt produces logic 0 at its output if only one input is logic 1

32. - E7B10

In Figure E7-1, what is the purpose of R1 and R2?

SelectAnswer
ASelf bias
BVoltage divider bias
CLoad resistors
DFeedback

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?

SelectAnswer
AGreater harmonic suppression
BDoes not require a capacitor
CGreater transformation range
DHigher efficiency

34. - E7D03

What device is typically used as a stable voltage reference in a linear voltage regulator?

SelectAnswer
AA tunnel diode
BAn SCR
CA Zener diode
DA varactor diode

35. - E7E06

Why is de-emphasis commonly used in FM communications receivers?

SelectAnswer
AFor higher efficiency
BTo reduce impulse noise reception
CTo remove third-order distortion products
DFor compatibility with transmitters using phase modulation

36. - E7F04

What is a common method of generating an SSB signal using digital signal processing?

SelectAnswer
AVarying quartz crystal characteristics emulated in digital form
BSignals are combined in quadrature phase relationship
CMixing products are converted to voltages and subtracted by adder circuits
DA frequency synthesizer removes the unwanted sidebands

37. - E7G09

What will be the output voltage of the circuit shown in Figure E7-3 if R1 is 1000 ohms, RF is 10,000 ohms, and 0.23 volts DC is applied to the input?

SelectAnswer
A-0.23 volts
B0.23 volts
C-2.3 volts
D2.3 volts

38. - E7H07

How can an oscillator's microphonic responses be reduced?

SelectAnswer
AIncrease the bias voltage
BUse NP0 capacitors
CReduce noise on the oscillator's power supply
DMechanically isolate the oscillator circuitry from its enclosure

39. - E8A07

What determines the PEP-to-average power ratio of a single-sideband phone signal?

SelectAnswer
ASpeech characteristics
BAmplifier gain
CThe degree of carrier suppression
DThe frequency of the modulating signal

40. - E8B03

What is the modulation index of an FM-phone signal having a maximum frequency deviation of 3000 Hz either side of the carrier frequency when the modulating frequency is 1000 Hz?

SelectAnswer
A0.3
B3000
C1000
D3

41. - E8C01

How is Forward Error Correction implemented?

SelectAnswer
ABy varying the frequency shift of the transmitted signal according to a predefined algorithm
BBy transmitting extra data that may be used to detect and correct transmission errors
CBy the receiving station repeating each block of three data characters
DBy transmitting a special algorithm to the receiving station along with the data characters

42. - E8D08

What parameter evaluates distortion of an AFSK signal caused by excessive input audio levels?

SelectAnswer
AIntermodulation Distortion (IMD)
BSignal-to-noise ratio
CBaud rate
DRepeat Request Rate (RRR)

43. - E9A13

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

SelectAnswer
AHalf-power bandwidth
BEffective radiated power
CApparent power
DPower factor

44. - E9B04

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

SelectAnswer
A28 dB
B38 dB
C15 dB
D3 dB

45. - E9C02

What is the radiation pattern of two 1/4-wavelength vertical antennas spaced 1/4 wavelength apart and fed 90 degrees out of phase?

SelectAnswer
AA figure-8 end-fire along the axis of the array
BCardioid
COmni-directional
DA figure-8 broadside to the axis of the array

46. - E9D07

What is an advantage of using top loading in a shortened HF vertical antenna?

SelectAnswer
AGreater structural strength
BHigher losses
CImproved radiation efficiency
DLower Q

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?

SelectAnswer
AThe delta matching system
BThe omega matching system
CThe stub matching system
DThe gamma matching system

48. - E9F12

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

SelectAnswer
AVery high impedance
BThe same as the input impedance to the generator
CVery low impedance
DThe same as the characteristic impedance of the line

49. - E9G02

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

SelectAnswer
AVoltage lines and current chords
BResistance circles and reactance arcs
CResistance lines and reactance chords
DVoltage circles and current arcs

50. - E9H02

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

SelectAnswer
AAll these choices are correct
BThey must be erected at least 1/2 wavelength above the ground to attain good directivity
CLow loss coax transmission line is essential for good performance
DAtmospheric noise is so high that gain over a dipole is not important

Figure E7-1

Figure E7-3