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

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1. - E0A01

What is the primary function of an external earth connection or ground rod?

Select	Answer
A	Reduce RF current flow between pieces of equipment
B	Reduce RFI to telephones and home entertainment systems
C	Lightning protection
D	Reduce received noise

2. - E1A14

Except in some parts of Alaska, what is the maximum power permitted on the 630 meter band?

Select	Answer
A	1 watt EIRP
B	50 watts PEP
C	5 watts EIRP
D	100 watts PEP

3. - E1B11

What does PRB-1 require of regulations affecting amateur radio?

Select	Answer
A	Reasonable accommodations of amateur radio must be made
B	Use of wireless devices in a vehicle is exempt from regulation
C	No limitations may be placed on antenna size or placement
D	Amateur radio operations must be permitted in any private residence

4. - E1C07

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

Select	Answer
A	3 dB
B	6 dB
C	23 dB
D	26 dB

5. - E1D01

What is the definition of telemetry?

Select	Answer
A	Two-way transmissions in excess of 1000 feet
B	One-way transmission of measurements at a distance from the measuring instrument
C	One-way transmission that initiates, modifies, or terminates the functions of a device at a distance
D	Two-way transmissions of data

6. - E1E06

Who is responsible for the proper conduct and necessary supervision during an amateur operator license examination session?

Select	Answer
A	Each administering VE
B	The VEC coordinating the session
C	The VE session manager
D	The FCC

7. - E1F09

Which of the following conditions apply when transmitting spread spectrum emissions?

Select	Answer
A	All these choices are correct
B	The transmission must not be used to obscure the meaning of any communication
C	The transmitting station must be in an area regulated by the FCC or in a country that permits SS emissions
D	A station transmitting SS emission must not cause harmful interference to other stations employing other authorized emissions

8. - E2A04

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

Select	Answer
A	Whether the satellite is in a polar or equatorial orbit
B	The satellite's orientation with respect to the Earth
C	The satellite's uplink and downlink frequency bands
D	Whether the satellite is in a low earth or geostationary orbit

9. - E2B10

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

Select	Answer
A	Tone amplitude
B	Sync amplitude
C	Sync frequency
D	Tone frequency

10. - E2C04

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

Select	Answer
A	HF frequencies where digital communications are permitted
B	The 60 meter band channel centered on 5373 kHz
C	Frequencies shared with various unlicensed wireless data services
D	Cable TV channels 41 through 43

11. - E2D03

Which of the following digital modes is especially useful for EME communications?

Select	Answer
A	PACTOR III
B	Olivia
C	MSK144
D	JT65

12. - E2E13

Which of these digital modes has the fastest data throughput under clear communication conditions?

Select	Answer
A	AMTOR
B	170 Hz shift, 45 baud RTTY
C	300 baud packet
D	PSK31

13. - E3A04

What do Hepburn maps predict?

Select	Answer
A	Locations of auroral reflecting zones
B	Likelihood of rain scatter along cold or warm fronts
C	Probability of tropospheric propagation
D	Sporadic E propagation

14. - E3B10

Why is chordal hop propagation desirable?

Select	Answer
A	The MUF for chordal hop propagation is much lower than for normal skip propagation
B	The signal experiences less loss compared to multi-hop using Earth as a reflector
C	Signals travel faster along ionospheric chords
D	Atmospheric noise is lower in the direction of chordal hop propagation

15. - E3C13

What type of polarization is best for ground-wave propagation?

Select	Answer
A	Horizontal
B	Circular
C	Elliptical
D	Vertical

16. - E4A03

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

Select	Answer
A	A logic analyzer
B	A wattmeter
C	A time-domain reflectometer
D	A spectrum analyzer

17. - E4B02

What is the significance of voltmeter sensitivity expressed in ohms per volt?

Select	Answer
A	The full scale reading of the voltmeter multiplied by its ohms per volt rating will indicate the input impedance of the voltmeter
B	When used as an ammeter, the full scale reading in amps divided by ohms per volt rating will determine the size of shunt needed
C	When used as a galvanometer, the reading in volts multiplied by the ohms per volt rating will determine the power drawn by the device under test
D	When used as an ohmmeter, the reading in ohms divided by the ohms per volt rating will determine the voltage applied to the circuit

18. - E4C05

What does a receiver noise floor of -174 dBm represent?

Select	Answer
A	The minimum detectable signal as a function of receive frequency
B	The theoretical noise in a 1 Hz bandwidth at the input of a perfect receiver at room temperature
C	The noise figure of a 1 Hz bandwidth receiver
D	The galactic noise contribution to minimum detectable signal

19. - E4D10

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

Select	Answer
A	Signals less than 40 dBm will not generate audible third-order intermodulation products
B	The receiver can tolerate signals up to 40 dB above the noise floor without producing third-order intermodulation products
C	A 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
D	A pair of 1 mW input signals will produce a third-order intermodulation product that is 40 dB stronger than the input signal

20. - E4E06

What is one type of electrical interference that might be caused by a nearby personal computer?

Select	Answer
A	The appearance of unstable modulated or unmodulated signals at specific frequencies
B	A whining type noise that continually pulses off and on
C	A clicking noise at intervals of a few seconds
D	A loud AC hum in the audio output of your station receiver

21. - E5A07

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

Select	Answer
A	Maximum
B	R/L
C	Minimum
D	L/R

22. - E5B04

What is the time constant of a circuit having two 220-microfarad capacitors and two 1-megohm resistors, all in parallel?

Select	Answer
A	220 seconds
B	110 seconds
C	55 seconds
D	440 seconds

23. - E5C09

When using rectangular coordinates to graph the impedance of a circuit, what do the axes represent?

Select	Answer
A	The X axis represents the reactive component and the Y axis represents the resistive component
B	The X axis represents the phase angle and the Y axis represents the magnitude
C	The X axis represents the resistive component and the Y axis represents the reactive component
D	The X axis represents the magnitude and the Y axis represents the phase angle

24. - E5D06

In what direction is the magnetic field oriented about a conductor in relation to the direction of electron flow?

Select	Answer
A	In a circle around the conductor
B	In a direction opposite to the current
C	In the same direction as the current
D	In all directions; omni-directional

25. - E6A01

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

Select	Answer
A	In high-power audio circuits
B	In microwave circuits
C	In very low-frequency RF circuits
D	In high-current rectifier circuits

26. - E6B01

What is the most useful characteristic of a Zener diode?

Select	Answer
A	An internal capacitance that varies with the applied voltage
B	A constant current drop under conditions of varying voltage
C	A negative resistance region
D	A constant voltage drop under conditions of varying current

27. - E6C05

What is an advantage of CMOS logic devices over TTL devices?

Select	Answer
A	Differential output capability
B	Lower distortion
C	Immune to damage from static discharge
D	Lower power consumption

28. - E6D07

What is current in the primary winding of a transformer called if no load is attached to the secondary?

Select	Answer
A	Direct current
B	Stabilizing current
C	Magnetizing current
D	Excitation current

29. - E6E07

What type of transmission line is used for connections to MMICs?

Select	Answer
A	Microstrip
B	Circular waveguide
C	Parallel wire
D	Miniature coax

30. - E6F04

What is the photovoltaic effect?

Select	Answer
A	The tendency of a battery to discharge when exposed to light
B	The conversion of light to electrical energy
C	The conversion of voltage to current when exposed to light
D	The conversion of electrical energy to mechanical energy

31. - E7A03

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

Select	Answer
A	An XOR gate
B	A flip-flop
C	An OR gate
D	A multiplexer

32. - E7B05

What can be done to prevent unwanted oscillations in an RF power amplifier?

Select	Answer
A	Tune both the input and output for maximum power
B	Install parasitic suppressors and/or neutralize the stage
C	Use a phase inverter in the output filter
D	Tune the stage for maximum SWR

33. - E7C05

Which filter type is described as having ripple in the passband and a sharp cutoff?

Select	Answer
A	A passive op-amp filter
B	An active LC filter
C	A Chebyshev filter
D	A Butterworth filter

34. - E7D14

What is the purpose of connecting equal-value resistors across power supply filter capacitors connected in series?

Select	Answer
A	Provide a minimum load on the supply
B	Equalize the voltage across each capacitor
C	All these choices are correct
D	Discharge the capacitors when voltage is removed

35. - E7E06

Why is de-emphasis commonly used in FM communications receivers?

Select	Answer
A	For compatibility with transmitters using phase modulation
B	To remove third-order distortion products
C	To reduce impulse noise reception
D	For higher efficiency

36. - E7F02

What kind of digital signal processing audio filter is used to remove unwanted noise from a received SSB signal?

Select	Answer
A	A Hilbert-transform filter
B	An adaptive filter
C	A phase-inverting filter
D	A crystal-lattice filter

37. - E7G05

How can unwanted ringing and audio instability be prevented in an op-amp RC audio filter circuit?

Select	Answer
A	Increase both gain and Q
B	Restrict both gain and Q
C	Restrict gain but increase Q
D	Restrict Q but increase gain

38. - E7H13

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

Select	Answer
A	Use a temperature-controlled high Q dielectric resonator
B	Use a rubidium stabilized reference oscillator
C	All these choices are correct
D	Use a GPS signal reference

39. - E8A06

What is the approximate ratio of PEP-to-average power in a typical single-sideband phone signal?

Select	Answer
A	25 to 1
B	100 to 1
C	2.5 to 1
D	1 to 1

40. - E8B11

What is digital time division multiplexing?

Select	Answer
A	Two or more data streams are assigned to discrete sub-carriers on an FM transmitter
B	Two or more signals are arranged to share discrete time slots of a data transmission
C	Two or more signals are quadrature modulated to increase bandwidth efficiency
D	Two or more data streams share the same channel by transmitting time of transmission as the sub-carrier

41. - E8C08

How does ARQ accomplish error correction?

Select	Answer
A	Special polynomial codes provide automatic correction
B	If errors are detected, a retransmission is requested
C	If errors are detected, redundant data is substituted
D	Special binary codes provide automatic correction

42. - E8D02

What spread spectrum communications technique uses a high-speed binary bit stream to shift the phase of an RF carrier?

Select	Answer
A	Phase compandored spread spectrum
B	Frequency hopping
C	Direct sequence
D	Binary phase-shift keying

43. - E9A10

Which of the following improves the efficiency of a ground-mounted quarter-wave vertical antenna?

Select	Answer
A	Installing a radial system
B	Isolating the coax shield from ground
C	All these choices are correct
D	Shortening the radiating element

44. - E9B08

What is the far field of an antenna?

Select	Answer
A	The region where radiated field strengths are constant
B	The region of the ionosphere where radiated power is not refracted
C	The region where the shape of the antenna pattern is independent of distance
D	The region where radiated power dissipates over a specified time period

45. - E9C09

Which of the following describes a G5RV antenna?

Select	Answer
A	A multi-band dipole antenna fed with coax and a balun through a selected length of open wire transmission line
B	A phased array antenna consisting of multiple loops
C	A wide band dipole using shorted coaxial cable for the radiating elements and fed with a�4:1 balun
D	A multi-band trap antenna

46. - E9D10

What happens to feed-point impedance at the base of a fixed length HF mobile antenna when operated below its resonant frequency?

Select	Answer
A	The radiation resistance decreases and the capacitive reactance increases
B	The radiation resistance increases and the capacitive reactance decreases
C	The radiation resistance increases and the capacitive reactance increases
D	The radiation resistance decreases and the capacitive reactance decreases

47. - E9E02

What is the name of an antenna matching system that matches an unbalanced feed line to an antenna by feeding the driven element both at the center of the element and at a fraction of a wavelength to one side of center?

Select	Answer
A	The gamma match
B	The stub match
C	The delta match
D	The epsilon match

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?

Select	Answer
A	10.4 meters
B	5.2 meters
C	8.3 meters
D	6.9 meters

49. - E9G03

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

Select	Answer
A	Trigonometric functions
B	Impedance and SWR values in transmission lines
C	Beam headings and radiation patterns
D	Satellite azimuth and elevation bearings

50. - E9H02

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

Select	Answer
A	All these choices are correct
B	Low loss coax transmission line is essential for good performance
C	They must be erected at least 1/2 wavelength above the ground to attain good directivity
D	Atmospheric noise is so high that gain over a dipole is not important