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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?

SelectAnswer
AEnsure signals from your station are less than the controlled Maximum Permitted Emission (MPE) limits
BEnsure signals from your station are less than the uncontrolled Maximum Permitted Emission (MPE) limits
CEnsure signals from your station are less than the uncontrolled Maximum Permitted Exposure (MPE) limits
DEnsure signals from your station are less than the controlled Maximum Permitted Exposure (MPE) limits

2. - E1A04

With your transceiver displaying the carrier frequency of phone signals, you hear a DX station calling CQ on 3.601 MHz LSB. Is it legal to return the call using lower sideband on the same frequency?

SelectAnswer
ANo, U.S. stations are not permitted to use phone emissions below 3.610 MHz
BYes, because the displayed frequency is within the 75 meter phone band segment
CNo, the sideband will extend beyond the edge of the phone band segment
DYes, because the DX station initiated the contact

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?

SelectAnswer
AThe amateur station must avoid transmitting during certain hours on frequencies that cause the interference
BThe amateur station must cease operation
CThe amateur station must cease operation on all frequencies above 30 MHz
DThe amateur station must cease operation on all frequencies below 30 MHz

4. - E1C11

Which of the following operating arrangements allows an FCC-licensed U.S. citizen to operate in many European countries, and alien amateurs from many European countries to operate in the U.S.?

SelectAnswer
AAll these choices are correct
BIARP agreement
CCEPT agreement
DITU reciprocal license

5. - E1D03

What is a space telecommand station?

SelectAnswer
AAn amateur station located on the surface of the Earth for communication with other Earth stations by means of Earth satellites
BAn amateur station located in a satellite or a balloon more than 50 kilometers above the surface of the Earth
CAn amateur station that transmits communications to initiate, modify or terminate functions of a space station
DAn amateur station that receives telemetry from a satellite or balloon more than 50 kilometers above the surface of the Earth

6. - E1E07

What should a VE do if a candidate fails to comply with the examiner's instructions during an amateur operator license examination?

SelectAnswer
AAllow the candidate to complete the examination, but invalidate the results
BImmediately terminate everyone's examination and close the session
CWarn the candidate that continued failure to comply will result in termination of the examination
DImmediately terminate the candidate's examination

7. - E1F10

Who may be the control operator of an auxiliary station?

SelectAnswer
AOnly General, Advanced or Amateur Extra Class operators
BOnly Amateur Extra Class operators
CAny licensed amateur operator
DOnly Technician, General, Advanced or Amateur Extra Class operators

8. - E2A11

What type of antenna can be used to minimize the effects of spin modulation and Faraday rotation?

SelectAnswer
AA linearly polarized antenna
BA circularly polarized antenna
CAn isotropic antenna
DA log-periodic dipole array

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 is sent in a color burst at the end of each line
DColor information is sent on a 2.8 kHz subcarrier

10. - E2C03

From which of the following bands is amateur radio contesting generally excluded?

SelectAnswer
A30 meters
B6 meters
C33 centimeters
D2 meters

11. - E2D04

What technology is used to track, in real time, balloons carrying amateur radio transmitters?

SelectAnswer
AAPRS
BBandwidth compressed LORAN
CUltrasonics
DDoppler shift of beacon signals

12. - E2E02

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

SelectAnswer
AFatal Error Correction
BForward Error Correction
CFirst Error Correction
DFinal Error Correction

13. - E3A03

When scheduling EME contacts, which of these conditions will generally result in the least path loss?

SelectAnswer
AWhen the MUF is above 30 MHz
BWhen the moon is full
CWhen the moon is at perigee
DWhen the moon is at apogee

14. - E3B01

What is transequatorial propagation?

SelectAnswer
APropagation between points located on the magnetic equator
BPropagation between points at the same latitude
CPropagation between a point on the equator and its antipodal point
DPropagation between two mid-latitude points at approximately the same distance north and south of the magnetic equator

15. - E3C02

What is indicated by a rising A or K index?

SelectAnswer
AIncreasing disruption of the geomagnetic field
BHigher levels of solar UV radiation
CAn increase in the critical frequency
DDecreasing disruption of the geomagnetic field

16. - E4A09

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

SelectAnswer
AKeep the signal ground connection of the probe as short as possible
BNever use a DC-coupled probe to measure an AC circuit
CNever use a high-impedance probe to measure a low-impedance circuit
DAll these choices are correct

17. - E4B03

Which S parameter is equivalent to forward gain?

SelectAnswer
AS21
BS22
CS12
DS11

18. - E4C12

Which of the following has the largest effect on an SDR receiver's dynamic range?

SelectAnswer
ARAM speed used for data storage
BCPU register width in bits
CAnti-aliasing input filter bandwidth
DAnalog-to-digital converter sample width in bits

19. - E4D09

What is the purpose of the preselector in a communications receiver?

SelectAnswer
ATo provide a range of AGC time constants
BTo allow selection of the optimum RF amplifier device
CTo increase rejection of signals outside the desired band
DTo store often-used frequencies

20. - E4E02

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

SelectAnswer
AAll these choices are correct
BIgnition noise
CPower line noise
DBroadband white noise

21. - E5A07

What is the magnitude of the current at the input of a parallel RLC circuit at resonance?

SelectAnswer
AMaximum
BR/L
CL/R
DMinimum

22. - E5B03

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

SelectAnswer
ASquare the magnitude and subtract 90 degrees from the angle
BTake the square root of the magnitude and add 180 degrees to the angle
CTake the reciprocal of the magnitude and change the sign of the angle
DTake the reciprocal of the angle and change the sign of the magnitude

23. - E5C11

Which point in Figure E5-1 best represents the impedance of a series circuit consisting of a 300-ohm resistor and an 18-microhenry inductor at 3.505 MHz?

SelectAnswer
APoint 1
BPoint 8
CPoint 7
DPoint 3

24. - E5D10

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

SelectAnswer
ABy multiplying the apparent power by the power factor
BBy dividing the apparent power by the power factor
CBy multiplying the reactive power by the power factor
DBy dividing the reactive power by the power factor

25. - E6A05

How does DC input impedance at the gate of a field-effect transistor compare with the DC input impedance of a bipolar transistor?

SelectAnswer
AThey are both high impedance
BAn FET has higher input impedance
CAn FET has lower input impedance
DThey are both low impedance

26. - E6B08

Which of the following is a Schottky barrier diode?

SelectAnswer
AThermionic emission diode
BMetal-semiconductor junction
CPIN junction
DElectrolytic rectifier

27. - E6C10

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

SelectAnswer
A2
B3
C1
D4

28. - E6D01

Why should core saturation of an impedance matching transformer be avoided?

SelectAnswer
AMagnetic flux would increase with frequency
BTemporary changes of the core permeability could result
CHarmonics and distortion could result
DRF susceptance would increase

29. - E6E10

What advantage does surface-mount technology offer at RF compared to using through-hole components?

SelectAnswer
AComponents have less parasitic inductance and capacitance
BShorter circuit-board traces
CAll these choices are correct
DSmaller circuit area

30. - E6F03

What is the most common configuration of an optoisolator or optocoupler?

SelectAnswer
AA frequency modulated helium-neon laser
BA lens and a photomultiplier
CAn LED and a phototransistor
DAn amplitude modulated helium-neon laser

31. - E7A02

What is the function of a decade counter?

SelectAnswer
AIt produces one output pulse for every 10 input pulses
BIt produces 10 output pulses for every input pulse
CIt decodes a binary number for display on a seven-segment LED display
DIt decodes a decimal number for display on a seven-segment LED display

32. - E7B03

Which of the following components form the output of a class D amplifier circuit?

SelectAnswer
AA temperature compensating load resistor to improve linearity
BA low-pass filter to remove switching signal components
CA matched load resistor to prevent damage by switching transients
DA high-pass filter to compensate for low gain at low frequencies

33. - E7C02

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

SelectAnswer
AIt is a notch filter
BIt is a high-pass filter
CIt is a band-pass filter
DIt is a low-pass filter

34. - E7D10

What is the primary reason that a high-frequency switching type high-voltage power supply can be both less expensive and lighter in weight than a conventional power supply?

SelectAnswer
AIt uses a large power factor compensation capacitor to recover power from the unused portion of the AC cycle
BIt uses a diode bridge rectifier for increased output
CThe inverter design does not require any output filtering
DThe high frequency inverter design uses much smaller transformers and filter components for an equivalent power output

35. - E7E08

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

SelectAnswer
AThe two input frequencies along with their sum and difference frequencies
BTwo and four times the original frequency
CThe square root of the product of input frequencies
D1.414 and 0.707 times the input frequency

36. - E7F09

Why is an anti-aliasing digital filter required in a digital decimator?

SelectAnswer
AIt peaks the response of the decimator, improving bandwidth
BIt notches out the sampling frequency to avoid sampling errors
CIt removes high-frequency signal components that would otherwise be reproduced as lower frequency components
DIt removes low-frequency signal components to eliminate the need for DC restoration

37. - E7G02

What is ringing in a filter?

SelectAnswer
AA reduction in high frequency response
BUndesired oscillations added to the desired signal
CPartial cancellation of the signal over a range of frequencies
DAn echo caused by a long time delay

38. - E7H04

How is positive feedback supplied in a Colpitts oscillator?

SelectAnswer
AThrough a capacitive divider
BThrough link coupling
CThrough a tapped coil
DThrough a neutralizing capacitor

39. - E8A10

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

SelectAnswer
ALower the input bandwidth to increase the effective resolution
BImprove accuracy by removing out-of-sequence codes from the input
CAll these choices are correct
DRemove harmonics from the output caused by the discrete analog levels generated

40. - E8B11

What is digital time division multiplexing?

SelectAnswer
ATwo or more data streams share the same channel by transmitting time of transmission as the sub-carrier
BTwo or more data streams are assigned to discrete sub-carriers on an FM transmitter
CTwo or more signals are quadrature modulated to increase bandwidth efficiency
DTwo or more signals are arranged to share discrete time slots of a data transmission

41. - E8C05

What is the approximate bandwidth of a 13-WPM International Morse Code transmission?

SelectAnswer
A104 Hz
B26 Hz
C52 Hz
D13 Hz

42. - E8D05

What is the most common method of reducing key clicks?

SelectAnswer
ALow-pass filters at the transmitter output
BHigh-pass filters at the transmitter output
CReduce keying waveform rise and fall times
DIncrease keying waveform rise and fall times

43. - E9A08

What is antenna bandwidth?

SelectAnswer
AAntenna length divided by the number of elements
BThe angle formed between two imaginary lines drawn through the element ends
CThe frequency range over which an antenna satisfies a performance requirement
DThe angle between the half-power radiation points

44. - E9B11

What is a disadvantage of decreasing the number of wire segments in an antenna model below 10 segments per half-wavelength?

SelectAnswer
AGround conductivity will not be accurately modeled
BThe antenna will become mechanically unstable
CThe computed feed point impedance may be incorrect
DThe resulting design will favor radiation of harmonic energy

45. - E9C10

Which of the following describes a Zepp antenna?

SelectAnswer
AAn end-fed dipole antenna
BA vertical array capable of quickly changing the direction of maximum radiation by changing phasing lines
CAn omni-directional antenna commonly used for satellite communications
DA dipole constructed from zip cord

46. - E9D05

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

SelectAnswer
AThe frequency response is widened over the whole frequency band
BThe front-to-back ratio increases
CThe SWR is reduced
DThe front-to-back ratio decreases

47. - E9E09

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

SelectAnswer
ADouble-bazooka match
BAll these choices are correct
CGamma match
DHairpin match

48. - E9F01

What is the velocity factor of a transmission line?

SelectAnswer
AThe velocity of the wave in the transmission line multiplied by the velocity of light in a vacuum
BThe index of shielding for coaxial cable
CThe velocity of the wave in the transmission line divided by the velocity of light in a vacuum
DThe ratio of the characteristic impedance of the line to the terminating impedance

49. - E9G07

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

SelectAnswer
AThe resistance axis
BThe voltage axis
CThe current axis
DThe reactance axis

50. - E9H08

What is the function of a sense antenna?

SelectAnswer
AIt increases the sensitivity of a DF antenna array
BIt modifies the pattern of a DF antenna array to provide a null in one direction
CIt provides diversity reception that cancels multipath signals
DIt allows DF antennas to receive signals at different vertical angles

Figure E5-1

Figure E6-3

Figure E9-3