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

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1. - E0A04

When evaluating a site with multiple transmitters operating at the same time, the operators and licensees of which transmitters are responsible for mitigating over-exposure situations?

Select	Answer
A	Each transmitter that produces 5 percent or more of its MPE limit in areas where the total MPE limit is exceeded.
B	Each transmitter operating with a duty cycle greater than 50 percent
C	Only the most powerful transmitter
D	Only commercial transmitters

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. - E1B10

What frequencies are authorized to an amateur station operating under RACES rules?

Select	Answer
A	Specific segments in the amateur service MF, HF, VHF and UHF bands
B	Military Auxiliary Radio System (MARS) channels
C	All amateur service frequencies authorized to the control operator
D	Specific local government channels

4. - E1C06

Which of the following is required in order to operate in accordance with CEPT rules in foreign countries where permitted?

Select	Answer
A	You must identify in the official language of the country in which you are operating
B	You must bring a copy of FCC Public Notice DA 16-1048
C	The U.S. embassy must approve of your operation
D	You must append "/CEPT" to your call sign

5. - E1D01

What is the definition of telemetry?

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

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

7. - E1F07

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

Select	Answer
A	When the control operator is employed by the FCC or another government agency
B	When neither the amateur nor his or her employer has a pecuniary interest in the communications
C	When transmitting international third-party communications
D	When the total money involved does not exceed $25

8. - E2A09

What do the terms L band and S band specify regarding satellite communications?

Select	Answer
A	The 2 meter and 70 centimeter bands
B	Which sideband to use
C	FM and Digital Store-and-Forward systems
D	The 23 centimeter and 13 centimeter bands

9. - E2B09

What hardware, other than a receiver with SSB capability and a suitable computer, is needed to decode SSTV using Digital Radio Mondiale (DRM)?

Select	Answer
A	A special front end limiter
B	A special IF converter
C	A special notch filter to remove synchronization pulses
D	No other hardware is needed

10. - E2C12

What technique do individual nodes use to form a mesh network?

Select	Answer
A	Acting as store-and-forward digipeaters
B	Discovery and link establishment protocols
C	Forward error correction and Viterbi codes
D	Custom code plugs for the local trunking systems

11. - E2D10

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

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

12. - E2E12

How do ALE stations establish contact?

Select	Answer
A	ALE radios send a constant tone code to establish a frequency for future use
B	ALE constantly scans a list of frequencies, activating the radio when the designated call sign is received
C	ALE radios monitor an internet site for the frequency they are being paged on
D	ALE radios activate when they hear their signal echoed by back scatter

13. - E3A01

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

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

14. - E3B01

What is transequatorial propagation?

Select	Answer
A	Propagation between a point on the equator and its antipodal point
B	Propagation between points at the same latitude
C	Propagation between points located on the magnetic equator
D	Propagation between two mid-latitude points at approximately the same distance north and south of the magnetic equator

15. - E3C09

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

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

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

17. - E4B11

Which of the following can be measured with a vector network analyzer?

Select	Answer
A	All these choices are correct
B	Input impedance
C	Output impedance
D	Reflection coefficient

18. - E4C04

What is the noise figure of a receiver?

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

19. - E4D02

Which of the following describes problems caused by poor dynamic range in a receiver?

Select	Answer
A	Spurious signals caused by cross-modulation and desensitization from strong adjacent signals
B	Cross-modulation of the desired signal and insufficient audio power to operate the speaker
C	Oscillator instability and severe audio distortion of all but the strongest received signals
D	Oscillator instability requiring frequent retuning and loss of ability to recover the opposite sideband

20. - E4E05

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

Select	Answer
A	By installing a high-pass filter in series with the motor's power leads
B	By using a ground-fault current interrupter in the circuit used to power the motor
C	By installing a bypass capacitor in series with the motor leads
D	By installing a brute-force AC-line filter in series with the motor leads

21. - E5A12

What is the half-power bandwidth of a resonant circuit that has a resonant frequency of 3.7 MHz and a Q of 118?

Select	Answer
A	31.4 kHz
B	15.7 kHz
C	218.3 kHz
D	436.6 kHz

22. - E5B11

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 25 ohms, R is 100 ohms, and XL is 50 ohms?

Select	Answer
A	76 degrees with the voltage lagging the current
B	14 degrees with the voltage lagging the current
C	76 degrees with the voltage leading the current
D	14 degrees with the voltage leading the current

23. - E5C11

Which point in Figure E5-1 best represents the impedance of a series circuit consisting of a 300-ohm resistor and an 18-microhenry inductor at 3.505 MHz?

Select	Answer
A	Point 7
B	Point 1
C	Point 3
D	Point 8

24. - E5D01

What is the result of skin effect?

Select	Answer
A	As frequency decreases, RF current flows in a thinner layer of the conductor, closer to the surface
B	Thermal effects on the surface of the conductor decrease the impedance
C	Thermal effects on the surface of the conductor increase the impedance
D	As frequency increases, RF current flows in a thinner layer of the conductor, closer to the surface

25. - E6A03

Why does a PN-junction diode not conduct current when reverse biased?

Select	Answer
A	Excess holes in P-type material combine with the electrons in N-type material, converting the entire diode into an insulator
B	Only N-type semiconductor material can conduct current
C	Holes in P-type material and electrons in the N-type material are separated by the applied voltage, widening the depletion region
D	Only P-type semiconductor material can conduct current

26. - E6B04

What type of semiconductor device is designed for use as a voltage-controlled capacitor?

Select	Answer
A	Tunnel diode
B	Varactor diode
C	Silicon-controlled rectifier
D	Zener diode

27. - E6C09

What is a Programmable Logic Device (PLD)?

Select	Answer
A	A type of transistor whose gain can be changed by digital logic circuits
B	A programmable collection of logic gates and circuits in a single integrated circuit
C	A logic circuit that can be modified during use
D	Programmable equipment used for testing digital logic integrated circuits

28. - E6D06

What core material property determines the inductance of an inductor?

Select	Answer
A	Reactivity
B	Permeability
C	Thermal impedance
D	Resistance

29. - E6E12

Why are DIP through-hole package ICs not typically used at UHF and higher frequencies?

Select	Answer
A	Too many pins
B	Unsuitable for combining analog and digital signals
C	Epoxy coating is conductive above 300 MHz
D	Excessive lead length

30. - E6F07

What is a solid-state relay?

Select	Answer
A	A semiconductor passive delay line
B	A relay using transistors to drive the relay coil
C	A mechanical relay that latches in the on or off state each time it is pulsed
D	A device that uses semiconductors to implement the functions of an electromechanical relay

31. - E7A05

Which of the following is a circuit that continuously alternates between two states without an external clock?

Select	Answer
A	Astable multivibrator
B	T flip-flop
C	J-K flip-flop
D	Monostable multivibrator

32. - E7B11

In Figure E7-1, what is the purpose of R3?

Select	Answer
A	Output load resistor
B	Self bias
C	Fixed bias
D	Emitter bypass

33. - E7C08

Which of the following factors has the greatest effect on the bandwidth and response shape of a crystal ladder filter?

Select	Answer
A	The gain of the RF stage preceding the filter
B	The relative frequencies of the individual crystals
C	The DC voltage applied to the quartz crystal
D	The amplitude of the signals passing through the filter

34. - E7D02

What is a characteristic of a switching electronic voltage regulator?

Select	Answer
A	It is generally less efficient than a linear regulator
B	The resistance of a control element is varied in direct proportion to the line voltage or load current
C	The controlled device's duty cycle is changed to produce a constant average output voltage
D	It gives a ramp voltage at its output

35. - E7E08

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

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

36. - E7F09

Why is an anti-aliasing digital filter required in a digital decimator?

Select	Answer
A	It removes low-frequency signal components to eliminate the need for DC restoration
B	It notches out the sampling frequency to avoid sampling errors
C	It peaks the response of the decimator, improving bandwidth
D	It removes high-frequency signal components that would otherwise be reproduced as lower frequency components

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	0.03
B	1
C	76
D	38

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

39. - E8A02

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

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

40. - E8B01

What is the modulation index of an FM signal?

Select	Answer
A	The ratio of frequency deviation to modulating signal frequency
B	The ratio of modulating signal amplitude to frequency deviation
C	The bandwidth of the transmitted signal divided by the modulating signal frequency
D	The type of modulation used by the transmitter

41. - E8C09

Which digital code allows only one bit to change between sequential code values?

Select	Answer
A	Gray code
B	Binary Coded Decimal Code
C	Extended Binary Coded Decimal Interchange Code
D	Excess 3 code

42. - E8D04

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

Select	Answer
A	Limits data speed
B	The generation of RF harmonics
C	More difficult to copy
D	The generation of key clicks

43. - E9A08

What is antenna bandwidth?

Select	Answer
A	Antenna length divided by the number of elements
B	The frequency range over which an antenna satisfies a performance requirement
C	The angle between the half-power radiation points
D	The angle formed between two imaginary lines drawn through the element ends

44. - E9B09

What type of computer program technique is commonly used for modeling antennas?

Select	Answer
A	Graphical analysis
B	Calculus differentiation with respect to physical properties
C	Method of Moments
D	Mutual impedance analysis

45. - E9C13

How does the radiation pattern of a horizontally polarized 3-element beam antenna vary with increasing height above ground?

Select	Answer
A	The horizontal beamwidth decreases
B	The takeoff angle of the lowest elevation lobe increases
C	The takeoff angle of the lowest elevation lobe decreases
D	The horizontal beamwidth increases

46. - E9D08

What happens as the Q of an antenna increases?

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

47. - E9E10

Which of these choices is an effective way to match an antenna with a 100-ohm feed point impedance to a 50-ohm coaxial cable feed line?

Select	Answer
A	Connect a 1/2 wavelength shorted stub of 75-ohm cable in parallel with the 50-ohm cable where it attaches to the antenna
B	Insert a 1/4-wavelength piece of 75-ohm coaxial cable transmission line in series between the antenna terminals and the 50-ohm feed cable
C	Insert a 1/2 wavelength piece of 300-ohm twinlead in series between the antenna terminals and the 50-ohm feed cable
D	Connect a 1/4-wavelength open stub of 300-ohm twinlead in parallel with the coaxial feed line where it connects to the antenna

48. - E9F04

What impedance does a 1/2-wavelength transmission line present to a generator when the line is shorted at the far end?

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

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	Reactance axis
C	Prime axis
D	Impedance axis

50. - E9H03

What is Receiving Directivity Factor (RDF)?

Select	Answer
A	Forward gain compared to the gain in the reverse direction
B	Relative directivity compared to a dipole
C	Forward gain compared to average gain over the entire hemisphere
D	Relative directivity compared to isotropic

Figure E5-1

Figure E7-1

Figure E7-3

Figure E9-3