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. - E0A10

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

SelectAnswer
APolytetrafluoroethylene
BPolyethylene
CPolymorphic silicon
DPolychlorinated biphenyls

2. - E1A10

If an amateur station is installed aboard a ship or aircraft, what condition must be met before the station is operated?

SelectAnswer
AThe amateur station operator must agree not to transmit when the main radio of the ship or aircraft is in use
BIts operation must be approved by the master of the ship or the pilot in command of the aircraft
CThe amateur station must have a power supply that is completely independent of the main ship or aircraft power supply
DThe amateur operator must have an FCC Marine or Aircraft endorsement on his or her amateur license

3. - E1B07

To what type of regulations does PRB-1 apply?

SelectAnswer
AFAA tower height limits
BUse of wireless devices in vehicles
CHomeowners associations
DState and local zoning

4. - E1C03

How do the control operator responsibilities of a station under automatic control differ from one under local control?

SelectAnswer
AUnder automatic control there is no control operator
BUnder local control a control operator is not required to be present at a control point
CUnder automatic control the control operator is not required to be present at the control point
DUnder local control there is no control operator

5. - E1D05

What must be posted at the station location of a station being operated by telecommand on or within 50 km of the earth's surface?

SelectAnswer
AAll these choices are correct
BA label with the name, address, and telephone number of the station licensee
CA photocopy of the station license
DA label with the name, address, and telephone number of the control operator

6. - E1E04

Which of the following best describes the Volunteer Examiner accreditation process?

SelectAnswer
AThe amateur operator applying must pass a VE examination administered by the FCC Enforcement Bureau
BThe prospective VE obtains accreditation from the FCC
CEach General, Advanced and Amateur Extra Class operator is automatically accredited as a VE when the license is granted
DThe procedure by which a VEC confirms that the VE applicant meets FCC requirements to serve as an examiner

7. - E1F01

On what frequencies are spread spectrum transmissions permitted?

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

8. - E2A02

Which of the following occurs when a satellite is using an inverting linear transponder?

SelectAnswer
ADoppler shift is reduced because the uplink and downlink shifts are in opposite directions
BSignal position in the band is reversed
CUpper sideband on the uplink becomes lower sideband on the downlink, and vice versa
DAll these choices are correct

9. - E2B12

What signals SSTV receiving software to begin a new picture line?

SelectAnswer
ASpecific tone frequencies
BA two-tone signal
CElapsed time
DSpecific tone amplitudes

10. - E2C08

Which of the following contacts may be confirmed through the U.S. QSL bureau system?

SelectAnswer
AContacts between a U.S. station and a non-U.S. station
BSpecial event contacts between stations in the U.S.
CRepeater contacts between U.S. club members
DContacts using tactical call signs

11. - E2D11

Which of the following data are used by the APRS network to communicate station location?

SelectAnswer
ATime and frequency
BLatitude and longitude
CRadio direction finding spectrum analysis
DPolar coordinates

12. - E2E04

What is indicated when one of the ellipses in an FSK crossed-ellipse display suddenly disappears?

SelectAnswer
AThe receiver has drifted 5 kHz from the desired receive frequency
BThe mark and space signal have been inverted
COne of the signal filters is saturated
DSelective fading has occurred

13. - E3A05

Tropospheric propagation of microwave signals often occurs in association with what phenomenon?

SelectAnswer
ASprites and jets
BWarm and cold fronts
CLightning discharges
DGrayline

14. - E3B12

What is the primary characteristic of chordal hop propagation?

SelectAnswer
APropagation away from the great circle bearing between stations
BSuccessive ionospheric refractions without an intermediate reflection from the ground
CPropagation across the geomagnetic equator
DSignals reflected back toward the transmitting station

15. - E3C02

What is indicated by a rising A or K index?

SelectAnswer
AAn increase in the critical frequency
BHigher levels of solar UV radiation
CDecreasing disruption of the geomagnetic field
DIncreasing disruption of the geomagnetic field

16. - E4A07

Which of the following is an advantage of using an antenna analyzer compared to an SWR bridge to measure antenna SWR?

SelectAnswer
AAntenna analyzers do not need an external RF source
BAntenna analyzers display a time-varying representation of the modulation envelope
CAntenna analyzers automatically tune your antenna for resonance
DAll these choices are correct

17. - E4B09

What is indicated if the current reading on an RF ammeter placed in series with the antenna feed line of a transmitter increases as the transmitter is tuned to resonance?

SelectAnswer
AThe transmitter is not properly neutralized
BThere is possibly a short to ground in the feed line
CThere is an impedance mismatch between the antenna and feed line
DThere is more power going into the antenna

18. - E4C08

An SDR receiver is overloaded when input signals exceed what level?

SelectAnswer
AOne-half the maximum sampling buffer size
BThe maximum count value of the analog-to-digital converter
COne-half the maximum sample rate
DThe reference voltage of the analog-to-digital converter

19. - E4D04

Which of the following may reduce or eliminate intermodulation interference in a repeater caused by another transmitter operating in close proximity?

SelectAnswer
AA band-pass filter in the feed line between the transmitter and receiver
BUtilizing a Class C final amplifier
CUtilizing a Class D final amplifier
DA properly terminated circulator at the output of the repeater's transmitter

20. - E4E05

How can radio frequency interference from an AC motor be suppressed?

SelectAnswer
ABy installing a brute-force AC-line filter in series with the motor leads
BBy using a ground-fault current interrupter in the circuit used to power the motor
CBy installing a high-pass filter in series with the motor's power leads
DBy installing a bypass capacitor in series with the motor leads

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. - 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
A76 degrees with the voltage lagging the current
B76 degrees with the voltage leading the current
C14 degrees with the voltage leading the current
D14 degrees with the voltage lagging the current

23. - E5C06

What does the impedance 50-j25 represent?

SelectAnswer
A50 ohms resistance in series with 25 ohms inductive reactance
B25 ohms resistance in series with 50 ohms capacitive reactance
C50 ohms resistance in series with 25 ohms capacitive reactance
D25 ohms resistance in series with 50 ohms inductive reactance

24. - E5D04

Why are short connections used at microwave frequencies?

SelectAnswer
ATo reduce noise figure
BTo reduce phase shift along the connection
CTo increase neutralizing resistance
DTo increase compensating capacitance

25. - E6A01

In what application is gallium arsenide used as a semiconductor material?

SelectAnswer
AIn high-current rectifier circuits
BIn microwave circuits
CIn high-power audio circuits
DIn very low-frequency RF circuits

26. - E6B07

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

SelectAnswer
AExcessive inverse voltage
BExcessive junction temperature
CCharge carrier depletion
DInsufficient forward voltage

27. - E6C02

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

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

28. - E6D02

What is the equivalent circuit of a quartz crystal?

SelectAnswer
AMotional capacitance, motional inductance, loss resistance, and a capacitor representing electrode and stray capacitance all in series
BMotional capacitance, motional inductance, and loss resistance in series, all in parallel with a shunt capacitor representing electrode and stray capacitance
CMotional inductance and loss resistance in series, paralleled with motional capacitance and a capacitor representing electrode and stray capacitance
DMotional capacitance, motional inductance, loss resistance, and a capacitor representing electrode and stray capacitance all in parallel

29. - E6E02

Which of the following device packages is a through-hole type?

SelectAnswer
ASOT
BDIP
CPLCC
DBall grid array

30. - E6F05

Which describes an optical shaft encoder?

SelectAnswer
AA device for generating RTTY signals by means of a rotating light source
BA digital encryption device often used to encrypt spacecraft control signals
CA device that detects rotation of a control by interrupting a light source with a patterned wheel
DA device that measures the strength of a beam of light using analog to digital conversion

31. - E7A03

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

SelectAnswer
AA flip-flop
BAn XOR gate
CA multiplexer
DAn OR gate

32. - E7B18

What is a characteristic of a grounded-grid amplifier?

SelectAnswer
AHigh filament voltage
BHigh power gain
CLow input impedance
DLow bandwidth

33. - E7C07

Which describes a Pi-L-network used for matching a vacuum tube final amplifier to a 50-ohm unbalanced output?

SelectAnswer
AA matching network in which all components are isolated from ground
BA Phase Inverter Load network
CA Pi-network with an additional series inductor on the output
DA network with only three discrete parts

34. - E7D05

Which of the following types of linear voltage regulator places a constant load on the unregulated voltage source?

SelectAnswer
AA series regulator
BA constant current source
CA shunt current source
DA shunt regulator

35. - E7E04

What is one way a single-sideband phone signal can be generated?

SelectAnswer
ABy driving a product detector with a DSB signal
BBy using a reactance modulator followed by a mixer
CBy using a loop modulator followed by a mixer
DBy using a balanced modulator followed by a filter

36. - E7F11

What sets the minimum detectable signal level for a direct-sampling SDR receiver in the absence of atmospheric or thermal noise?

SelectAnswer
AMissing codes and jitter
BData storage transfer rate
CSample clock phase noise
DReference voltage level and sample width in bits

37. - E7G02

What is ringing in a filter?

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

38. - E7H07

How can an oscillator's microphonic responses be reduced?

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

39. - E8A02

Which of the following is a type of analog-to-digital conversion?

SelectAnswer
ALevel shifting
BPhase reversal
CSuccessive approximation
DHarmonic regeneration

40. - E8B11

What is digital time division multiplexing?

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

41. - E8C10

How may data rate be increased without increasing bandwidth?

SelectAnswer
AUsing forward error correction
BUsing a more efficient digital code
CIt is impossible
DIncreasing analog-to-digital conversion resolution

42. - E8D04

What is the primary effect of extremely short rise or fall time on a CW signal?

SelectAnswer
AThe generation of key clicks
BThe generation of RF harmonics
CMore difficult to copy
DLimits data speed

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
A317 watts
B300 watts
C2000 watts
D126 watts

44. - E9B07

How does the total amount of radiation emitted by a directional gain antenna compare with the total amount of radiation emitted from a theoretical isotropic antenna, assuming each is driven by the same amount of power?

SelectAnswer
AThe radiation from the isotropic antenna is 2.15 dB stronger than that from the directional antenna
BThe total amount of radiation from the directional antenna is increased by the gain of the antenna
CThe total amount of radiation from the directional antenna is stronger by its front-to-back ratio
DThey are the same

45. - E9C07

What is the approximate feed point impedance at the center of a two-wire folded dipole antenna?

SelectAnswer
A450 ohms
B300 ohms
C50 ohms
D72 ohms

46. - E9D11

Which of the following conductors would be best for minimizing losses in a station's RF ground system?

SelectAnswer
AStranded wire
BSolid wire
CResistive wire, such as spark plug wire
DWide flat copper strap

47. - E9E11

What is the primary purpose of phasing lines when used with an antenna having multiple driven elements?

SelectAnswer
AIt ensures that each driven element operates in concert with the others to create the desired antenna pattern
BIt creates a low-angle radiation pattern
CIt allows single-band antennas to operate on other bands
DIt prevents reflected power from traveling back down the feed line and causing harmonic radiation from the transmitter

48. - E9F03

Why is the physical length of a coaxial cable transmission line shorter than its electrical length?

SelectAnswer
AThe surge impedance is higher in a parallel feed line
BThe characteristic impedance is higher in a parallel feed line
CSkin effect is less pronounced in the coaxial cable
DElectrical signals move more slowly in a coaxial cable than in air

49. - E9G07

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

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

50. - E9H05

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

SelectAnswer
AIt has a bidirectional pattern
BAll these choices are correct
CIt has no clearly defined null
DIt is practical for use only on VHF and higher bands