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

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1. - E0A08

What does SAR measure?

Select	Answer
A	Signal Amplification Rating
B	The rate of RF energy reflected from stationary terrain
C	Synthetic Aperture Ratio of the human body
D	The rate at which RF energy is absorbed by the body

2. - E1A14

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

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

3. - E1B03

Within what distance must an amateur station protect an FCC monitoring facility from harmful interference?

Select	Answer
A	1 mile
B	10 miles
C	30 miles
D	3 miles

4. - E1C12

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

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

5. - E1D01

What is the definition of telemetry?

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

6. - E1E01

For which types of out-of-pocket expenses do the Part 97 rules state that VEs and VECs may be reimbursed?

Select	Answer
A	Teaching an amateur operator license examination preparation course
B	Preparing, processing, administering, and coordinating an examination for an amateur radio operator license
C	No expenses are authorized for reimbursement
D	Providing amateur operator license examination preparation training materials

7. - E1F09

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

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

8. - E2A12

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

Select	Answer
A	To relay messages between satellites
B	To store digital messages in the satellite for later download by other stations
C	To delay download of telemetry between satellites
D	To upload operational software for the transponder

9. - E2B07

What is the name of the signal component that carries color information in NTSC video?

Select	Answer
A	Hue
B	Luminance
C	Spectral intensity
D	Chroma

10. - E2C03

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

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

11. - E2D10

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

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

12. - E2E07

Which of the following is a possible reason that attempts to initiate contact with a digital station on a clear frequency are unsuccessful?

Select	Answer
A	The protocol version you are using is not supported by the digital station
B	Another station you are unable to hear is using the frequency
C	All these choices are correct
D	Your transmit frequency is incorrect

13. - E3A13

Which of these emission modes is best for auroral propagation?

Select	Answer
A	CW
B	FM
C	RTTY
D	SSB

14. - E3B06

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

Select	Answer
A	10 meters
B	20 meters
C	80 meters
D	6 meters

15. - E3C09

How does the intensity of an X3 flare compare to that of an X2 flare?

Select	Answer
A	10 percent greater
B	Twice as great
C	Four times as great
D	50 percent greater

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 spectrum analyzer
C	A wattmeter
D	A time-domain reflectometer

17. - E4B01

Which of the following factors most affects the accuracy of a frequency counter?

Select	Answer
A	Temperature coefficient of the logic
B	Decade divider accuracy
C	Time base accuracy
D	Input attenuator accuracy

18. - E4C04

What is the noise figure of a receiver?

Select	Answer
A	The ratio of the noise bandwidth in hertz to the theoretical bandwidth of a resistive network
B	The ratio of thermal noise to atmospheric noise
C	The ratio of atmospheric noise to phase noise
D	The ratio in dB of the noise generated by the receiver to the theoretical minimum noise

19. - E4D07

Which of the following reduces the likelihood of receiver desensitization?

Select	Answer
A	Decrease the RF bandwidth of the receiver
B	Increase the receiver front end gain
C	Raise the receiver IF frequency
D	Switch from fast AGC to slow AGC

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

21. - E5A15

Which of the following increases Q for inductors and capacitors?

Select	Answer
A	Lower reactance
B	Lower self-resonant frequency
C	Lower losses
D	Higher self-resonant frequency

22. - E5B05

What happens to the magnitude of a pure reactance when it is converted to a susceptance?

Select	Answer
A	It is unchanged
B	It is shifted by 90 degrees
C	The sign is reversed
D	It becomes the reciprocal

23. - E5C05

What is the name of the diagram used to show the phase relationship between impedances at a given frequency?

Select	Answer
A	Far field diagram
B	Near field diagram
C	Phasor diagram
D	Venn diagram

24. - E5D11

What is the power factor of an RL circuit having a 60-degree phase angle between the voltage and the current?

Select	Answer
A	0.866
B	0.5
C	1.414
D	1.73

25. - E6A04

What is the name given to an impurity atom that adds holes to a semiconductor crystal structure?

Select	Answer
A	Insulator impurity
B	N-type impurity
C	Acceptor impurity
D	Donor impurity

26. - E6B07

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

Select	Answer
A	Insufficient forward voltage
B	Charge carrier depletion
C	Excessive junction temperature
D	Excessive inverse voltage

27. - E6C10

In Figure E6-3, what is the schematic symbol for a NOR gate?

Select	Answer
A	1
B	2
C	4
D	3

28. - E6D11

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

Select	Answer
A	Ferrite
B	Powdered iron
C	Brass
D	Ceramic

29. - E6E05

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

Select	Answer
A	-20 dBm
B	44 dBm
C	2 dB
D	-10 dB

30. - E6F05

Which describes an optical shaft encoder?

Select	Answer
A	A device that measures the strength of a beam of light using analog to digital conversion
B	A device for generating RTTY signals by means of a rotating light source
C	A digital encryption device often used to encrypt spacecraft control signals
D	A device that detects rotation of a control by interrupting a light source with a patterned wheel

31. - E7A01

Which circuit is bistable?

Select	Answer
A	A flip-flop
B	A bipolar amplifier
C	An AND gate
D	An OR gate

32. - E7B08

How can an RF power amplifier be neutralized?

Select	Answer
A	By increasing the driving power
B	By feeding an in-phase component of the output back to the input
C	By feeding a 180-degree out-of-phase portion of the output back to the input
D	By reducing the driving power

33. - E7C11

Which of the following describes a receiving filter's ability to reject signals occupying an adjacent channel?

Select	Answer
A	Passband ripple
B	Noise factor
C	Shape factor
D	Phase response

34. - E7D07

What is the purpose of C2 in the circuit shown in Figure E7-2?

Select	Answer
A	To self-resonate at the hum frequency
B	It bypasses rectifier output ripple around D1
C	It is a brute force filter for the output
D	To provide fixed DC bias for Q1

35. - E7E08

What are the principal frequencies that appear at the output of a mixer circuit?

Select	Answer
A	The two input frequencies along with their sum and difference frequencies
B	The square root of the product of input frequencies
C	Two and four times the original frequency
D	1.414 and 0.707 times the input frequency

36. - E7F05

How frequently must an analog signal be sampled by an analog-to-digital converter so that the signal can be accurately reproduced?

Select	Answer
A	At least half the rate of the highest frequency component of the signal
B	At the same rate as the highest frequency component of the signal
C	At four times the rate of the highest frequency component of the signal
D	At least twice the rate of the highest frequency component of the signal

37. - E7G10

What absolute voltage gain can be expected from the circuit in Figure E7-3 when R1 is 1800 ohms and RF is 68 kilohms?

Select	Answer
A	38
B	76
C	0.03
D	1

38. - E7H04

How is positive feedback supplied in a Colpitts oscillator?

Select	Answer
A	Through a capacitive divider
B	Through a neutralizing capacitor
C	Through link coupling
D	Through a tapped coil

39. - E8A02

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

Select	Answer
A	Successive approximation
B	Phase reversal
C	Harmonic regeneration
D	Level shifting

40. - E8B10

What is frequency division multiplexing?

Select	Answer
A	Two or more information streams are merged into a baseband, which then modulates the transmitter
B	The transmitted signal jumps from band to band at a predetermined rate
C	Two or more information streams are merged into a digital combiner, which then pulse position modulates the transmitter
D	The transmitted signal is divided into packets of information

41. - E8C03

Why should phase-shifting of a PSK signal be done at the zero crossing of the RF signal?

Select	Answer
A	To minimize bandwidth
B	To improve carrier suppression
C	To simplify modulation
D	All these choices are correct

42. - E8D03

How does the spread spectrum technique of frequency hopping work?

Select	Answer
A	A binary bit stream is used to shift the phase of an RF carrier very rapidly in a pseudorandom sequence
B	If interference is detected by the receiver it will signal the transmitter to change frequencies
C	If interference is detected by the receiver it will signal the transmitter to wait until the frequency is clear
D	The frequency of the transmitted signal is changed very rapidly according to a pseudorandom sequence also used by the receiving station

43. - E9A02

What is the effective radiated power relative to a dipole of a repeater station with 150 watts transmitter power output, 2 dB feed line loss, 2.2 dB duplexer loss, and 7 dBd antenna gain?

Select	Answer
A	286 watts
B	78.7 watts
C	1977 watts
D	420 watts

44. - E9B05

What type of antenna pattern is shown in Figure E9-2?

Select	Answer
A	Elevation
B	Polarization
C	Radiation resistance
D	Azimuth

45. - E9C09

Which of the following describes a G5RV antenna?

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

46. - E9D06

What happens to the SWR bandwidth when one or more loading coils are used to resonate an electrically short antenna?

Select	Answer
A	It is unchanged if the loading coil is located at a voltage maximum point
B	It is unchanged if the loading coil is located at the feed point
C	It is decreased
D	It is increased

47. - E9E11

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

Select	Answer
A	It allows single-band antennas to operate on other bands
B	It creates a low-angle radiation pattern
C	It ensures that each driven element operates in concert with the others to create the desired antenna pattern
D	It prevents reflected power from traveling back down the feed line and causing harmonic radiation from the transmitter

48. - E9F12

What impedance does a 1/4-wavelength transmission line present to a generator when the line is open at the far end?

Select	Answer
A	Very high impedance
B	The same as the input impedance to the generator
C	The same as the characteristic impedance of the line
D	Very low impedance

49. - E9G10

What do the arcs on a Smith chart represent?

Select	Answer
A	Points with constant reactance
B	SWR
C	Points with constant resistance
D	Frequency

50. - E9H02

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

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

Figure E6-3

Figure E7-2

Figure E7-3

Figure E9-2