Anonymous User

Hamboozler

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

Logging in (or registering) will help the system to select questions that you need to focus on.

1. - E0A07

How may dangerous levels of carbon monoxide from an emergency generator be detected?

SelectAnswer
ABy the yellowish appearance of the gas
BAny ordinary smoke detector can be used
COnly with a carbon monoxide detector
DBy the odor

2. - E1A12

What special operating frequency restrictions are imposed on slow scan TV transmissions?

SelectAnswer
AThey are restricted to 7.245 MHz, 14.245 MHz, 21.345 MHz, and 28.945 MHz
BThey are restricted to phone band segments
CThey are not permitted above 54 MHz
DNone; they are allowed on all amateur frequencies

3. - E1B05

What is the National Radio Quiet Zone?

SelectAnswer
AAn area in Florida surrounding Cape Canaveral
BAn area surrounding the National Radio Astronomy Observatory
CAn area in Puerto Rico surrounding the Arecibo Radio Telescope
DAn area in New Mexico surrounding the White Sands Test Area

4. - E1C07

At what level below a signal's mean power level is its bandwidth determined according to FCC rules?

SelectAnswer
A6 dB
B26 dB
C3 dB
D23 dB

5. - E1D10

Which amateur stations are eligible to be telecommand stations of space stations (subject to the privileges of the class of operator license held by the control operator of the station)?

SelectAnswer
AAll these choices are correct
BAny amateur station designated by NASA
CAny amateur station so designated by the space station licensee
DAny amateur station so designated by the ITU

6. - E1E10

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

SelectAnswer
AThey must collect and send the documents to the NCVEC for grading
BThey must submit the application document to the coordinating VEC according to the coordinating VEC instructions
CThey must collect and submit the documents to the coordinating VEC for grading
DThey must collect and send the documents to the FCC according to instructions

7. - E1F10

Who may be the control operator of an auxiliary station?

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

8. - E2A04

What is meant by the term mode? as applied to an amateur radio satellite?

SelectAnswer
AWhether the satellite is in a low earth or geostationary orbit
BThe satellite's uplink and downlink frequency bands
CThe satellite's orientation with respect to the Earth
DWhether the satellite is in a polar or equatorial orbit

9. - E2B10

What aspect of an analog slow-scan television signal encodes the brightness of the picture?

SelectAnswer
ASync frequency
BTone amplitude
CSync amplitude
DTone frequency

10. - E2C04

Which of the following frequencies are sometimes used for amateur radio mesh networks?

SelectAnswer
AHF frequencies where digital communications are permitted
BFrequencies shared with various unlicensed wireless data services
CThe 60 meter band channel centered on 5373 kHz
DCable TV channels 41 through 43

11. - E2D05

What is one advantage of the JT65 mode?

SelectAnswer
APermits fast-scan TV transmissions over narrow bandwidth
BEasily copied by ear if necessary
CThe ability to decode signals which have a very low signal-to-noise ratio
DUses only a 65 Hz bandwidth

12. - E2E06

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

SelectAnswer
A48 baud
B300 baud
C110 baud
D1200 baud

13. - E3A09

Which of the following frequency ranges is most suited for meteor scatter communications?

SelectAnswer
A28 MHz - 148 MHz
B220 MHz - 450 MHz
C10 MHz - 14 MHz
D1.8 MHz - 1.9 MHz

14. - E3B06

Which of the following amateur bands most frequently provides long-path propagation?

SelectAnswer
A10 meters
B80 meters
C20 meters
D6 meters

15. - E3C01

What does the radio communication term "ray tracing" describe?

SelectAnswer
AThe process in which an electronic display presents a pattern
BDetermining the radiation pattern from an array of antennas
CModeling a radio wave's path through the ionosphere
DEvaluating high voltage sources for x-rays

16. - E4A03

Which of the following test instruments is used to display spurious signals and/or intermodulation distortion products generated by an SSB transmitter?

SelectAnswer
AA spectrum analyzer
BA wattmeter
CA time-domain reflectometer
DA logic analyzer

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?

SelectAnswer
A75 watts
B100 watts
C125 watts
D25 watts

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
ACapture effect
BCross-modulation interference
CFrequency discrimination
DDesensitization

19. - E4D10

What does a third-order intercept level of 40 dBm mean with respect to receiver performance?

SelectAnswer
ASignals less than 40 dBm will not generate audible third-order intermodulation products
BA pair of 1 mW input signals will produce a third-order intermodulation product that is 40 dB stronger than the input signal
CThe receiver can tolerate signals up to 40 dB above the noise floor without producing third-order intermodulation products
DA pair of 40 dBm input signals will theoretically generate a third-order intermodulation product that has the same output amplitude as either of the input signals

20. - E4E11

What could cause local AM broadcast band signals to combine to generate spurious signals in the MF or HF bands?

SelectAnswer
AYou are receiving skywave signals from a distant station
BOne or more of the broadcast stations is transmitting an over-modulated signal
CYour station receiver IF amplifier stage is defective
DNearby corroded metal joints are mixing and re-radiating the broadcast signals

21. - E5A05

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

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

22. - E5B07

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 500 ohms, R is 1 kilohm, and XL is 250 ohms?

SelectAnswer
A14.0 degrees with the voltage lagging the current
B68.2 degrees with the voltage lagging the current
C68.2 degrees with the voltage leading the current
D14.0 degrees with the voltage leading the current

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 3
DPoint 7

24. - E5D12

How many watts are consumed in a circuit having a power factor of 0.2 if the input is 100 VAC at 4 amperes?

SelectAnswer
A2000 watts
B50 watts
C80 watts
D400 watts

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?

SelectAnswer
AAlpha rejection frequency
BAlpha cutoff frequency
CCorner frequency
DBeta cutoff frequency

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?

SelectAnswer
AMuch higher reverse voltage breakdown
BMore constant reverse avalanche voltage
CLess forward voltage drop
DLonger carrier retention time

27. - E6C03

What is tri-state logic?

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

28. - E6D11

Which type of core material decreases inductance when inserted into a coil?

SelectAnswer
APowdered iron
BCeramic
CFerrite
DBrass

29. - E6E12

Why are DIP through-hole package ICs not typically used at UHF and higher frequencies?

SelectAnswer
AExcessive lead length
BEpoxy coating is conductive above 300 MHz
CUnsuitable for combining analog and digital signals
DToo many pins

30. - E6F03

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

SelectAnswer
AAn amplitude modulated helium-neon laser
BAn LED and a phototransistor
CA lens and a photomultiplier
DA frequency modulated helium-neon laser

31. - E7A03

Which of the following can divide the frequency of a pulse train by 2?

SelectAnswer
AAn XOR gate
BA multiplexer
CAn OR gate
DA flip-flop

32. - E7B14

Why are switching amplifiers more efficient than linear amplifiers?

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

33. - E7C10

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

SelectAnswer
AA cavity filter
BA crystal filter
CA DSP filter
DAn L-C filter

34. - E7D15

What is the purpose of a step-start circuit in a high-voltage power supply?

SelectAnswer
ATo allow for remote control of the power supply
BTo provide a dual-voltage output for reduced power applications
CTo compensate for variations of the incoming line voltage
DTo allow the filter capacitors to charge gradually

35. - E7E11

Which type of detector circuit is used for demodulating SSB signals?

SelectAnswer
AProduct detector
BPhase detector
CDiscriminator
DPhase comparator

36. - E7F03

What type of digital signal processing filter is used to generate an SSB signal?

SelectAnswer
AAn elliptical filter
BAn adaptive filter
CA Hilbert-transform filter
DA notch filter

37. - E7G04

What is meant by the "op-amp input offset voltage"?

SelectAnswer
AThe potential between the amplifier input terminals of the op-amp in an open loop condition
BThe differential input voltage needed to bring the open loop output voltage to zero
CThe difference between the output voltage of the op-amp and the input voltage required in the immediately following stage
DThe output voltage of the op-amp minus its input voltage

38. - E7H13

Which of the following is a technique for providing highly accurate and stable oscillators needed for microwave transmission and reception?

SelectAnswer
AAll these choices are correct
BUse a GPS signal reference
CUse a rubidium stabilized reference oscillator
DUse a temperature-controlled high Q dielectric resonator

39. - E8A05

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

SelectAnswer
AAn absorption wave meter
BA grid dip meter
CA D'Arsonval meter
DA true-RMS calculating meter

40. - E8B04

What is the modulation index of an FM-phone signal having a maximum carrier deviation of plus or minus 6 kHz when modulated with a 2 kHz modulating frequency?

SelectAnswer
A6000
B3
C1/3
D2000

41. - E8C08

How does ARQ accomplish error correction?

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

42. - E8D08

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

SelectAnswer
AIntermodulation Distortion (IMD)
BBaud rate
CRepeat Request Rate (RRR)
DSignal-to-noise ratio

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?

SelectAnswer
A300 watts
B2000 watts
C317 watts
D126 watts

44. - E9B02

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

SelectAnswer
A18 dB
B24 dB
C14 dB
D36 dB

45. - E9C13

How does the radiation pattern of a horizontally polarized 3-element beam antenna vary with increasing height above ground?

SelectAnswer
AThe takeoff angle of the lowest elevation lobe decreases
BThe takeoff angle of the lowest elevation lobe increases
CThe horizontal beamwidth increases
DThe horizontal beamwidth decreases

46. - E9D01

How much does the gain of an ideal parabolic dish antenna change when the operating frequency is doubled?

SelectAnswer
A2 dB
B3 dB
C4 dB
D6 dB

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

48. - E9F09

What is the approximate physical length of a foam polyethylene dielectric coaxial transmission line that is electrically 1/4 wavelength long at 7.2 MHz?

SelectAnswer
A10.4 meters
B6.9 meters
C8.3 meters
D5.2 meters

49. - E9G05

Which of the following is a common use for a Smith chart?

SelectAnswer
ADetermine the impedance of a transmission line, given the physical dimensions
BDetermine the loss/100 feet of a transmission line, given the velocity factor and conductor materials
CDetermine the length and position of an impedance matching stub
DDetermine the gain of an antenna given the physical and electrical parameters

50. - E9H07

Why is RF attenuation used when direction-finding?

SelectAnswer
ATo narrow the receiver bandwidth
BTo prevent receiver overload which reduces pattern nulls
CTo increase receiver sensitivity
DTo compensate for isotropic directivity and the antenna effect of feed lines

Figure E5-1

Figure E9-1