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?

Select	Answer
A	300 to 3000 MHz
B	300 kHz to 3 MHz
C	30 to 300 MHz
D	3 to 30 MHz

2. - E1A01

Which of the following carrier frequencies is illegal for LSB AFSK emissions on the 17 meter band RTTY and data segment of 18.068 to 18.110 MHz?

Select	Answer
A	18.100 MHz
B	18.068 MHz
C	18.110 MHz
D	18.107 MHz

3. - E1B11

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

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

4. - E1C12

On what portion of the 630 meter band are phone emissions permitted?

Select	Answer
A	Only the top 3 kHz
B	Only the bottom 3 kHz
C	The entire band
D	None

5. - E1D03

What is a space telecommand station?

Select	Answer
A	An amateur station that transmits communications to initiate, modify or terminate functions of a space station
B	An amateur station that receives telemetry from a satellite or balloon more than 50 kilometers above the surface of the Earth
C	An amateur station located on the surface of the Earth for communication with other Earth stations by means of Earth satellites
D	An amateur station located in a satellite or a balloon more than 50 kilometers above the surface of the Earth

6. - E1E10

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

Select	Answer
A	They must collect and send the documents to the NCVEC for grading
B	They must submit the application document to the coordinating VEC according to the coordinating VEC instructions
C	They must collect and submit the documents to the coordinating VEC for grading
D	They must collect and send the documents to the FCC according to instructions

7. - E1F03

Under what circumstances may a dealer sell an external RF power amplifier capable of operation below 144 MHz if it has not been granted FCC certification?

Select	Answer
A	The equipment dealer assembled it from a kit
B	It was imported from a manufacturer in another country and was certificated by that country's government
C	It was imported from a manufacturer in a country that does not require certification of RF power amplifiers
D	It was purchased in used condition from an amateur operator and is sold to another amateur operator for use at that operator's station

8. - E2A11

What type of antenna can be used to minimize the effects of spin modulation and Faraday rotation?

Select	Answer
A	A circularly polarized antenna
B	An isotropic antenna
C	A log-periodic dipole array
D	A linearly polarized antenna

9. - E2B03

How is an interlaced scanning pattern generated in a fast-scan (NTSC) television system?

Select	Answer
A	By scanning each field from bottom to top
B	By scanning lines from left to right in one field and right to left in the next
C	By scanning odd numbered lines in one field and even numbered lines in the next
D	By scanning two fields simultaneously

10. - E2C03

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

Select	Answer
A	2 meters
B	30 meters
C	6 meters
D	33 centimeters

11. - E2D10

How can an APRS station be used to help support a public service communications activity?

Select	Answer
A	An APRS station with an emergency medical technician can automatically transmit medical data to the nearest hospital
B	An APRS station with a Global Positioning System unit can automatically transmit information to show a mobile station's position during the event
C	All these choices are correct
D	APRS stations with General Personnel Scanners can automatically relay the participant numbers and time as they pass the check points

12. - E2E02

What do the letters FEC mean as they relate to digital operation?

Select	Answer
A	First Error Correction
B	Final Error Correction
C	Fatal Error Correction
D	Forward Error Correction

13. - E3A01

What is the approximate maximum separation measured along the surface of the Earth between two stations communicating by EME?

Select	Answer
A	5000 miles, if the moon is at perigee
B	500 miles, if the moon is at perigee
C	2000 miles, if the moon is at apogee
D	12,000 miles, if the moon is visible by both stations

14. - E3B03

What is the best time of day for transequatorial propagation?

Select	Answer
A	Noon
B	Afternoon or early evening
C	Morning
D	Late at night

15. - E3C13

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

Select	Answer
A	Elliptical
B	Vertical
C	Circular
D	Horizontal

16. - E4A08

Which of the following measures SWR?

Select	Answer
A	A spectrum analyzer
B	An antenna analyzer
C	An ohmmeter
D	A Q meter

17. - E4B03

Which S parameter is equivalent to forward gain?

Select	Answer
A	S21
B	S22
C	S12
D	S11

18. - E4C06

A CW receiver with the AGC off has an equivalent input noise power density of -174 dBm/Hz. What would be the level of an unmodulated carrier input to this receiver that would yield an audio output SNR of 0 dB in a 400 Hz noise bandwidth?

Select	Answer
A	-174 dBm
B	-155 dBm
C	-164 dBm
D	-148 dBm

19. - E4D12

What is the term for the reduction in receiver sensitivity caused by a strong signal near the received frequency?

Select	Answer
A	Squelch gain rollback
B	Cross-modulation interference
C	Quieting
D	Desensitization

20. - E4E10

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

Select	Answer
A	Arcing contacts in a thermostatically controlled device
B	A defective doorbell or doorbell transformer inside a nearby residence
C	A malfunctioning illuminated advertising display
D	All these choices are correct

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?

Select	Answer
A	1.78 MHz
B	22.36 MHz
C	3.56 MHz
D	44.72 MHz

22. - E5B09

What is the relationship between the AC current through a capacitor and the voltage across a capacitor?

Select	Answer
A	Current leads voltage by 90 degrees
B	Voltage leads current by 90 degrees
C	Voltage and current are in phase
D	Voltage and current are 180 degrees out of phase

23. - E5C01

Which of the following represents capacitive reactance in rectangular notation?

Select	Answer
A	+jX
B	Delta
C	-jX
D	Omega

24. - E5D02

Why is it important to keep lead lengths short for components used in circuits for VHF and above?

Select	Answer
A	To avoid unwanted inductive reactance
B	All these choices are correct
C	To increase the thermal time constant
D	To maintain component lifetime

25. - E6A06

What is the beta of a bipolar junction transistor?

Select	Answer
A	The breakdown voltage of the base to collector junction
B	The frequency at which the current gain is reduced to 0.707
C	The switching speed
D	The change in collector current with respect to base current

26. - E6B06

Which of the following is a common use of a Schottky diode?

Select	Answer
A	As a rectifier in high current power supplies
B	As a constant voltage reference in a power supply
C	As a variable capacitance in an automatic frequency control circuit
D	As a VHF/UHF mixer or detector

27. - E6C07

What best describes a pull-up or pull-down resistor?

Select	Answer
A	A resistor that ensures that an oscillator frequency does not drift
B	A resistor connected to the positive or negative supply line used to establish a voltage when an input or output is an open circuit
C	A resistor in a keying circuit used to reduce key clicks
D	A resistor connected to an op-amp output that prevents signals from exceeding the power supply voltage

28. - E6D03

Which of the following is an aspect of the piezoelectric effect?

Select	Answer
A	Mechanical deformation of material by the application of a voltage
B	Increased conductivity in the presence of light
C	Mechanical deformation of material by the application of a magnetic field
D	Generation of electrical energy in the presence of light

29. - E6E07

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

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

30. - E6F04

What is the photovoltaic effect?

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

31. - E7A09

What logical operation is performed by an exclusive NOR gate?

Select	Answer
A	It produces logic 1 at its output only if all inputs are logic 1
B	It produces logic 0 at its output if only one input is logic 1
C	It produces logic 0 at its output only if all inputs are logic 0
D	It produces logic 1 at its output if only one input is logic 1

32. - E7B12

What type of amplifier circuit is shown in Figure E7-1?

Select	Answer
A	Emitter follower
B	Common base
C	Common collector
D	Common emitter

33. - E7C10

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

Select	Answer
A	An L-C filter
B	A crystal filter
C	A DSP filter
D	A cavity filter

34. - E7D06

What is the purpose of Q1 in the circuit shown in Figure E7-2?

Select	Answer
A	It controls the current supplied to the load
B	It provides negative feedback to improve regulation
C	It provides D1 with current
D	It provides a constant load for the voltage source

35. - E7E01

Which of the following can be used to generate FM phone emissions?

Select	Answer
A	A reactance modulator on the oscillator
B	A reactance modulator on the final amplifier
C	A balanced modulator on the audio amplifier
D	A balanced modulator on the oscillator

36. - E7F03

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

Select	Answer
A	An adaptive filter
B	An elliptical filter
C	A Hilbert-transform filter
D	A notch filter

37. - E7G03

What is the typical input impedance of an op-amp?

Select	Answer
A	Very low
B	100 ohms
C	Very high
D	1000 ohms

38. - E7H01

What are three oscillator circuits used in amateur radio equipment?

Select	Answer
A	Colpitts, Hartley and Pierce
B	Pierce, Fenner and Beane
C	Taft, Hartley and Pierce
D	Taft, Pierce and negative feedback

39. - E8A11

Which of the following is a measure of the quality of an analog-to-digital converter?

Select	Answer
A	Reciprocal mixing
B	Total harmonic distortion
C	Power factor
D	Peak envelope power

40. - E8B02

How does the modulation index of a phase-modulated emission vary with RF carrier frequency?

Select	Answer
A	It decreases as the RF carrier frequency increases
B	It does not depend on the RF carrier frequency
C	It increases as the RF carrier frequency increases
D	It varies with the square root of the RF carrier frequency

41. - E8C10

How may data rate be increased without increasing bandwidth?

Select	Answer
A	Using a more efficient digital code
B	It is impossible
C	Increasing analog-to-digital conversion resolution
D	Using forward error 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	Direct sequence
B	Frequency hopping
C	Phase compandored spread spectrum
D	Binary phase-shift keying

43. - E9A05

What is included in the total resistance of an antenna system?

Select	Answer
A	Radiation resistance plus space impedance
B	Radiation resistance plus transmission resistance
C	Radiation resistance plus loss resistance
D	Transmission-line resistance plus radiation resistance

44. - E9B11

What is a disadvantage of decreasing the number of wire segments in an antenna model below 10 segments per half-wavelength?

Select	Answer
A	The computed feed point impedance may be incorrect
B	The resulting design will favor radiation of harmonic energy
C	The antenna will become mechanically unstable
D	Ground conductivity will not be accurately modeled

45. - E9C14

How does the performance of a horizontally polarized antenna mounted on the side of a hill compare with the same antenna mounted on flat ground?

Select	Answer
A	The horizontal beamwidth increases in the uphill direction
B	The main lobe takeoff angle increases in the downhill direction
C	The horizontal beamwidth decreases in the downhill direction
D	The main lobe takeoff angle decreases in the downhill direction

46. - E9D08

What happens as the Q of an antenna increases?

Select	Answer
A	SWR bandwidth decreases
B	More common-mode current is present on the feed line
C	SWR bandwidth increases
D	Gain is reduced

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 delta match
B	The gamma match
C	The stub match
D	The epsilon match

48. - E9F08

Which of the following is a significant difference between foam dielectric coaxial cable and solid dielectric cable, assuming all other parameters are the same?

Select	Answer
A	Foam dielectric has higher velocity factor
B	All these choices are correct
C	Foam dielectric has lower safe operating voltage limits
D	Foam dielectric has lower loss per unit of length

49. - E9G06

On the Smith chart shown in Figure E9-3, what is the name for the large outer circle on which the reactance arcs terminate?

Select	Answer
A	Polar axis
B	Impedance axis
C	Prime axis
D	Reactance axis

50. - E9H02

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

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

Figure E7-1

Figure E7-2

Figure E9-3