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

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1. - E0A10

What toxic material may be present in some electronic components such as high voltage capacitors and transformers?

SelectAnswer
APolyethylene
BPolytetrafluoroethylene
CPolymorphic silicon
DPolychlorinated biphenyls

2. - E1A06

Where must the carrier frequency of a CW signal be set to comply with FCC rules for 60 meter operation?

SelectAnswer
AAt the lowest frequency of the channel
BOn any frequency where the signal's sidebands are within the channel
CAt the center frequency of the channel
DAt the highest frequency of the channel

3. - E1B10

What frequencies are authorized to an amateur station operating under RACES rules?

SelectAnswer
AMilitary Auxiliary Radio System (MARS) channels
BAll amateur service frequencies authorized to the control operator
CSpecific segments in the amateur service MF, HF, VHF and UHF bands
DSpecific local government channels

4. - E1C05

When may an automatically controlled station originate third party communications?

SelectAnswer
ANever
BOnly when transmitting RTTY or data emissions
CWhen agreed upon by the sending or receiving station
DWhen approved by the National Telecommunication and Information Administration

5. - E1D09

Which UHF amateur bands have frequencies authorized for space stations?

SelectAnswer
A33 cm and 13 cm
B70 cm and 13 cm
C70 cm only
D70 cm and 33 cm

6. - E1E03

What is a Volunteer Examiner Coordinator?

SelectAnswer
AA person who has volunteered to prepare amateur operator license examinations
BAn organization that has entered into an agreement with the FCC to coordinate, prepare, and administer amateur operator license examinations
CThe person who has entered into an agreement with the FCC to be the VE session manager
DA person who has volunteered to administer amateur operator license examinations

7. - E1F01

On what frequencies are spread spectrum transmissions permitted?

SelectAnswer
AOnly on amateur frequencies above 144 MHz
BOnly on amateur frequencies above 222 MHz
COnly on amateur frequencies above 50 MHz
DOnly on amateur frequencies above 420 MHz

8. - E2A07

Which of the following types of signals can be relayed through a linear transponder?

SelectAnswer
APSK and packet
BSSB and SSTV
CFM and CW
DAll these choices are correct

9. - E2B02

How many horizontal lines make up a fast-scan (NTSC) television frame?

SelectAnswer
A60
B525
C30
D1080

10. - E2C07

What is the Cabrillo format?

SelectAnswer
AA standard for submission of electronic contest logs
BThe rules of order for meetings between contest sponsors
CThe most common set of contest rules
DA method of exchanging information during a contest QSO

11. - E2D02

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

SelectAnswer
A15-second timed transmission sequences with stations alternating based on location
BAll these choices are correct
CShort transmissions with rapidly repeated call signs and signal reports
DUse of special digital modes

12. - E2E03

How is the timing of FT4 contacts organized?

SelectAnswer
ABy exchanging ACK/NAK packets
BStations take turns on alternate days
CAlternating transmissions at 7.5 second intervals
DIt depends on the lunar phase

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. - E3B04

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

SelectAnswer
AExtraordinary waves describe rare long-skip propagation compared to ordinary waves, which travel shorter distances
BLong-path and short-path waves
CRefracted rays and reflected waves
DIndependent waves created in the ionosphere that are elliptically polarized

15. - E3C03

Which of the following signal paths is most likely to experience high levels of absorption when the A index or K index is elevated?

SelectAnswer
ATransequatorial
BPolar
CSporadic E
DNVIS

16. - E4A04

How is the compensation of an oscilloscope probe typically adjusted?

SelectAnswer
AA high frequency sine wave is displayed and the probe is adjusted for maximum amplitude
BA DC voltage standard is displayed and the probe is adjusted until the displayed voltage is accurate
CA square wave is displayed and the probe is adjusted until the horizontal portions of the displayed wave are as nearly flat as possible
DA frequency standard is displayed and the probe is adjusted until the deflection time is accurate

17. - E4B08

Which of the following can be used to measure the Q of a series-tuned circuit?

SelectAnswer
AThe inductance to capacitance ratio
BThe bandwidth of the circuit's frequency response
CThe frequency shift
DThe resonant frequency of the circuit

18. - E4C03

What is the term for the suppression in an FM receiver of one signal by another stronger signal on the same frequency?

SelectAnswer
AFrequency discrimination
BCross-modulation interference
CCapture effect
DDesensitization

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?

SelectAnswer
A146.34 MHz and 146.61 MHz
B173.35 MHz and 139.40 MHz
C146.88 MHz and 146.34 MHz
D146.10 MHz and 147.30 MHz

20. - E4E10

What might be the cause of a loud roaring or buzzing AC line interference that comes and goes at intervals?

SelectAnswer
AA defective doorbell or doorbell transformer inside a nearby residence
BAll these choices are correct
CA malfunctioning illuminated advertising display
DArcing contacts in a thermostatically controlled device

21. - E5A16

What is the resonant frequency of an RLC circuit if R is 33 ohms, L is 50 microhenries and C is 10 picofarads?

SelectAnswer
A7.12 MHz
B23.5 MHz
C23.5 kHz
D7.12 kHz

22. - E5B02

What letter is commonly used to represent susceptance?

SelectAnswer
AG
BX
CY
DB

23. - E5C12

Which point on Figure E5-1 best represents the impedance of a series circuit consisting of a 300-ohm resistor and a 19-picofarad capacitor at 21.200 MHz?

SelectAnswer
APoint 1
BPoint 3
CPoint 7
DPoint 8

24. - E5D07

How many watts are consumed in a circuit having a power factor of 0.71 if the apparent power is 500VA?

SelectAnswer
A704 W
B252 W
C355 W
D1.42 mW

25. - E6A03

Why does a PN-junction diode not conduct current when reverse biased?

SelectAnswer
AHoles in P-type material and electrons in the N-type material are separated by the applied voltage, widening the depletion region
BOnly P-type semiconductor material can conduct current
COnly N-type semiconductor material can conduct current
DExcess holes in P-type material combine with the electrons in N-type material, converting the entire diode into an insulator

26. - E6B07

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

SelectAnswer
ACharge carrier depletion
BInsufficient forward voltage
CExcessive inverse voltage
DExcessive junction temperature

27. - E6C02

What happens when the level of a comparator's input signal crosses the threshold?

SelectAnswer
AThe feedback loop becomes unstable
BThe comparator enters latch-up
CThe IC input can be damaged
DThe comparator changes its output state

28. - E6D05

What is one reason for using ferrite cores rather than powdered iron in an inductor?

SelectAnswer
AFerrite toroids generally require fewer turns to produce a given inductance value
BFerrite toroids generally have lower initial permeability
CFerrite toroids generally have better temperature stability
DFerrite toroids are easier to use with surface mount technology

29. - E6E11

What is a characteristic of DIP packaging used for integrated circuits?

SelectAnswer
ALow leakage doubly insulated package
BPackage mounts in a direct inverted position
CTwo chips in each package (Dual In Package)
DA total of two rows of connecting pins placed on opposite sides of the package (Dual In-line Package)

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. - E7A04

How many flip-flops are required to divide a signal frequency by 4?

SelectAnswer
A8
B4
C1
D2

32. - E7B14

Why are switching amplifiers more efficient than linear amplifiers?

SelectAnswer
ASwitching amplifiers operate at higher voltages
BThe power transistor is at saturation or cutoff most of the time
CLinear amplifiers have high gain resulting in higher harmonic content
DSwitching amplifiers use push-pull circuits

33. - E7C10

Which of the following filters would be the best choice for use in a 2 meter band repeater duplexer?

SelectAnswer
AA DSP filter
BAn L-C filter
CA crystal filter
DA cavity filter

34. - E7D02

What is a characteristic of a switching electronic voltage regulator?

SelectAnswer
AIt gives a ramp voltage at its output
BThe resistance of a control element is varied in direct proportion to the line voltage or load current
CThe controlled device's duty cycle is changed to produce a constant average output voltage
DIt is generally less efficient than a linear regulator

35. - E7E05

What circuit is added to an FM transmitter to boost the higher audio frequencies?

SelectAnswer
AA heterodyne suppressor
BA heterodyne enhancer
CA de-emphasis network
DA pre-emphasis network

36. - E7F13

What is the function of taps in a digital signal processing filter?

SelectAnswer
AProvide incremental signal delays for filter algorithms
BTo reduce excess signal pressure levels
CProvide access for debugging software
DSelect the point at which baseband signals are generated

37. - E7G02

What is ringing in a filter?

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

38. - E7H09

What type of frequency synthesizer circuit uses a phase accumulator, lookup table, digital to analog converter, and a low-pass anti-alias filter?

SelectAnswer
AA direct digital synthesizer
BA phase-locked loop synthesizer
CA diode-switching matrix synthesizer
DA hybrid synthesizer

39. - E8A07

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

SelectAnswer
AAmplifier gain
BThe degree of carrier suppression
CSpeech characteristics
DThe frequency of the modulating signal

40. - E8B07

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

SelectAnswer
AHigh-speed digital modes
BExtremely low-power contacts
CEME
DOFDM signals are not allowed on amateur bands

41. - E8C08

How does ARQ accomplish error correction?

SelectAnswer
AIf errors are detected, a retransmission is requested
BSpecial binary codes provide automatic correction
CSpecial polynomial codes provide automatic correction
DIf errors are detected, redundant data is substituted

42. - E8D07

What is a common cause of overmodulation of AFSK signals?

SelectAnswer
ABit errors in the modem
BExcessive transmit audio levels
CGround loops
DExcessive numbers of retries

43. - E9A02

What is the effective radiated power relative to a dipole of a repeater station with 150 watts transmitter power output, 2 dB feed line loss, 2.2 dB duplexer loss, and 7 dBd antenna gain?

SelectAnswer
A1977 watts
B286 watts
C420 watts
D78.7 watts

44. - E9B02

In the antenna radiation pattern shown in Figure E9-1, what is the front-to-back ratio?

SelectAnswer
A14 dB
B36 dB
C18 dB
D24 dB

45. - E9C08

What is a folded dipole antenna?

SelectAnswer
AA half-wave dipole with an additional parallel wire connecting its two ends
BA dipole one-quarter wavelength long
CA dipole configured to provide forward gain
DA type of ground-plane antenna

46. - E9D03

Where should a high Q loading coil be placed to minimize losses in a shortened vertical antenna?

SelectAnswer
AAs low as possible on the vertical radiator
BAt a voltage node
CAs close to the transmitter as possible
DNear the center of the vertical radiator

47. - E9E09

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

SelectAnswer
ADouble-bazooka match
BHairpin match
CAll these choices are correct
DGamma match

48. - E9F13

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

SelectAnswer
AThe same as the generator output impedance
BVery high impedance
CVery low impedance
DThe same as the characteristic impedance of the transmission line

49. - E9G02

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

SelectAnswer
AResistance circles and reactance arcs
BResistance lines and reactance chords
CVoltage circles and current arcs
DVoltage lines and current chords

50. - E9H11

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

SelectAnswer
AHigh radiation angle
BA very sharp peak
CA very sharp single null
DBroadband response

Figure E5-1

Figure E9-1