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

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1. - E0A03

Over what range of frequencies are the FCC human body RF exposure limits most restrictive?

SelectAnswer
A300 kHz to 3 MHz
B30 to 300 MHz
C3 to 30 MHz
D300 to 3000 MHz

2. - E1A09

What action or actions should you take if your digital message forwarding station inadvertently forwards a communication that violates FCC rules?

SelectAnswer
ANotify the originating station that the communication does not comply with FCC rules
BDiscontinue forwarding the communication as soon as you become aware of it
CNotify the nearest FCC Field Engineers office
DAll these choices are correct

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

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. - E1D03

What is a space telecommand station?

SelectAnswer
AAn amateur station located in a satellite or a balloon more than 50 kilometers above the surface of the Earth
BAn amateur station located on the surface of the Earth for communication with other Earth stations by means of Earth satellites
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. - E1E03

What is a Volunteer Examiner Coordinator?

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

7. - E1F07

When may an amateur station send a message to a business?

SelectAnswer
AWhen the control operator is employed by the FCC or another government agency
BWhen the total money involved does not exceed $25
CWhen neither the amateur nor his or her employer has a pecuniary interest in the communications
DWhen transmitting international third-party communications

8. - E2A12

What is the purpose of digital store-and-forward functions on an amateur radio satellite?

SelectAnswer
ATo relay messages between satellites
BTo delay download of telemetry between satellites
CTo upload operational software for the transponder
DTo store digital messages in the satellite for later download by other stations

9. - E2B08

What technique allows commercial analog TV receivers to be used for fast-scan TV operations on the 70 cm band?

SelectAnswer
AUsing USB and demodulating the signal with a computer sound card
BTransmitting on channels shared with cable TV
CUsing converted satellite TV dishes
DTransmitting on the abandoned TV channel 2

10. - E2C03

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

SelectAnswer
A2 meters
B30 meters
C33 centimeters
D6 meters

11. - E2D04

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

SelectAnswer
ABandwidth compressed LORAN
BDoppler shift of beacon signals
CUltrasonics
DAPRS

12. - E2E09

Which of the following HF digital modes uses variable-length coding for bandwidth efficiency?

SelectAnswer
AMT63
BRTTY
CPACTOR
DPSK31

13. - E3A04

What do Hepburn maps predict?

SelectAnswer
AProbability of tropospheric propagation
BLocations of auroral reflecting zones
CLikelihood of rain scatter along cold or warm fronts
DSporadic E propagation

14. - E3B03

What is the best time of day for transequatorial propagation?

SelectAnswer
ANoon
BMorning
CAfternoon or early evening
DLate at night

15. - E3C01

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

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

16. - E4A11

How should an antenna analyzer be connected when measuring antenna resonance and feed point impedance?

SelectAnswer
ALoosely couple the antenna and a dummy load to the analyzer
BLoosely couple the analyzer near the antenna base
CConnect the analyzer via a high-impedance transformer to the antenna
DConnect the antenna feed line directly to the analyzer's connector

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. - E4C04

What is the noise figure of a receiver?

SelectAnswer
AThe ratio of the noise bandwidth in hertz to the theoretical bandwidth of a resistive network
BThe ratio of thermal noise to atmospheric noise
CThe ratio of atmospheric noise to phase noise
DThe ratio in dB of the noise generated by the receiver to the theoretical minimum noise

19. - E4D01

What is meant by the blocking dynamic range of a receiver?

SelectAnswer
AThe minimum difference in dB between two signals which produce third-order intermodulation products greater than the noise floor
BThe difference in dB between the noise floor and the third-order intercept point
CThe minimum difference in dB between the levels of two FM signals that will cause one signal to block the other
DThe difference in dB between the noise floor and the level of an incoming signal that will cause 1 dB of gain compression

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. - E5A14

What is the resonant frequency of an RLC circuit if R is 22 ohms, L is 50 microhenries and C is 40 picofarads?

SelectAnswer
A44.72 MHz
B1.78 MHz
C22.36 MHz
D3.56 MHz

22. - E5B06

What is susceptance?

SelectAnswer
AThe ratio of magnetic field to electric field
BThe imaginary part of admittance
CThe magnetic impedance of a circuit
DA measure of the efficiency of a transformer

23. - E5C10

Which point on Figure E5-1 best represents the impedance of a series circuit consisting of a 400-ohm resistor and a 38-picofarad capacitor at 14 MHz?

SelectAnswer
APoint 2
BPoint 6
CPoint 4
DPoint 5

24. - E5D03

What is microstrip?

SelectAnswer
AShort lengths of coax mounted on printed circuit boards to minimize time delay between microwave circuits
BMiniature coax used for low power applications
CLightweight transmission line made of common zip cord
DPrecision printed circuit conductors above a ground plane that provide constant impedance interconnects at microwave frequencies

25. - E6A11

In Figure E6-1, what is the schematic symbol for a P-channel junction FET?

SelectAnswer
A6
B3
C1
D2

26. - E6B11

What is used to control the attenuation of RF signals by a PIN diode?

SelectAnswer
AA sub-harmonic pump signal
BForward DC bias current
CReverse voltage larger than the RF signal
DCapacitance of an RF coupling capacitor

27. - E6C08

In Figure E6-3, what is the schematic symbol for a NAND gate?

SelectAnswer
A3
B2
C1
D4

28. - E6D04

Which materials are commonly used as a core in an inductor?

SelectAnswer
APolystyrene and polyethylene
BTeflon and Delrin
CFerrite and brass
DCobalt and aluminum

29. - E6E05

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

SelectAnswer
A-20 dBm
B2 dB
C44 dBm
D-10 dB

30. - E6F02

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

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

31. - E7A07

What logical operation does a NAND gate perform?

SelectAnswer
AIt produces logic 0 at its output only when all inputs are logic 0
BIt produces logic 0 at its output if some but not all inputs are logic 1
CIt produces logic 0 at its output only when all inputs are logic 1
DIt produces logic 1 at its output only when all inputs are logic 1

32. - E7B04

Where on the load line of a Class A common emitter amplifier would bias normally be set?

SelectAnswer
AWhere the load line intersects the voltage axis
BAt a point where the load line intersects the zero bias current curve
CAt a point where the bias resistor equals the load resistor
DApproximately halfway between saturation and cutoff

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

34. - E7D09

What is the main reason to use a charge controller with a solar power system?

SelectAnswer
APrevention of battery undercharge
BPrevention of battery damage due to overcharge
CMatching of day and night charge rates
DControl of electrolyte levels during battery discharge

35. - E7E04

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

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

36. - E7F07

What function is performed by a Fast Fourier Transform?

SelectAnswer
AConverting digital signals to analog form
BConverting analog signals to digital form
CConverting digital signals from the time domain to the frequency domain
DConverting 8-bit data to 16-bit data

37. - E7G02

What is ringing in a filter?

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

38. - E7H03

How is positive feedback supplied in a Hartley oscillator?

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

39. - E8A04

What is "dither" with respect to analog-to-digital converters?

SelectAnswer
AA method of decimation by randomly skipping samples
BAn error caused by irregular quantization step size
CAn abnormal condition where the converter cannot settle on a value to represent the signal
DA small amount of noise added to the input signal to allow more precise representation of a signal over time

40. - E8B01

What is the modulation index of an FM signal?

SelectAnswer
AThe type of modulation used by the transmitter
BThe ratio of modulating signal amplitude to frequency deviation
CThe ratio of frequency deviation to modulating signal frequency
DThe bandwidth of the transmitted signal divided by the modulating signal frequency

41. - E8C04

What technique minimizes the bandwidth of a PSK31 signal?

SelectAnswer
AZero-sum character encoding
BUse of trapezoidal data pulses
CReed-Solomon character encoding
DUse of sinusoidal data pulses

42. - E8D04

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

SelectAnswer
AMore difficult to copy
BThe generation of RF harmonics
CThe generation of key clicks
DLimits data speed

43. - E9A12

How much gain does an antenna have compared to a 1/2-wavelength dipole when it has 6 dB gain over an isotropic antenna?

SelectAnswer
A8.15 dB
B2.79 dB
C6.0 dB
D3.85 dB

44. - E9B03

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

SelectAnswer
A14 dB
B24 dB
C18 dB
D12 dB

45. - E9C03

What is the radiation pattern of two 1/4-wavelength vertical antennas spaced 1/2-wavelength apart and fed in phase?

SelectAnswer
ACardioid
BA Figure-8 end-fire along the axis of the array
CA Figure-8 broadside to the axis of the array
DOmni-directional

46. - E9D12

Which of the following would provide the best RF ground for your station?

SelectAnswer
AAn electrically short connection to 3 or 4 interconnected ground rods driven into the Earth
BAn electrically short connection to a metal water pipe
CA 50-ohm resistor connected to ground
DAn electrically short connection to 3 or 4 interconnected ground rods via a series RF choke

47. - E9E04

What is the purpose of the series capacitor in a gamma-type antenna matching network?

SelectAnswer
ATo provide DC isolation between the feed line and the antenna
BTo provide a rejection notch that prevents the radiation of harmonics
CTo cancel the inductive reactance of the matching network
DTo transform the antenna impedance to a higher value

48. - E9F03

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

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

49. - E9G03

Which of the following is often determined using a Smith chart?

SelectAnswer
ASatellite azimuth and elevation bearings
BTrigonometric functions
CBeam headings and radiation patterns
DImpedance and SWR values in transmission lines

50. - E9H02

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

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

Figure E5-1

Figure E6-1

Figure E6-3

Figure E9-1