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

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1. - E0A09

Which insulating material commonly used as a thermal conductor for some types of electronic devices is extremely toxic if broken or crushed and the particles are accidentally inhaled?

Select	Answer
A	Beryllium Oxide
B	Zinc oxide
C	Uranium Hexafluoride
D	Mica

2. - E1A09

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

Select	Answer
A	Notify the nearest FCC Field Engineers office
B	Discontinue forwarding the communication as soon as you become aware of it
C	All these choices are correct
D	Notify the originating station that the communication does not comply with FCC rules

3. - E1B06

Which of the following additional rules apply if you are installing an amateur station antenna at a site at or near a public use airport?

Select	Answer
A	You must obtain a construction permit from the airport zoning authority
B	You may have to notify the Federal Aviation Administration and register it with the FCC as required by Part 17 of the FCC rules
C	You must file an Environmental Impact Statement with the EPA before construction begins
D	You must submit engineering drawings to the FAA

4. - E1C01

What is the maximum bandwidth for a data emission on 60 meters?

Select	Answer
A	1.5 kHz
B	60 Hz
C	2.8 kHz
D	170 Hz

5. - E1D07

Which HF amateur bands have frequencies authorized for space stations?

Select	Answer
A	Only the 40, 20, 17, 15, 12, and 10 meter bands
B	Only the 40, 30, 20, 15, 12, and 10 meter bands
C	Only the 40, 20, 17, 15, and 10 meter bands
D	All HF bands

6. - E1E11

What must the VE team do if an examinee scores a passing grade on all examination elements needed for an upgrade or new license?

Select	Answer
A	Three VEs must certify that the examinee is qualified for the license grant and that they have complied with the administering VE requirements
B	Photocopy all examination documents and forward them to the FCC for processing
C	Issue the examinee the new or upgrade license
D	All these choices are correct

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

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. - E2B02

How many horizontal lines make up a fast-scan (NTSC) television frame?

Select	Answer
A	60
B	1080
C	30
D	525

10. - E2C06

During a VHF/UHF contest, in which band segment would you expect to find the highest level of SSB or CW activity?

Select	Answer
A	In the middle of the band, usually 25 kHz above the national calling frequency
B	At the top of each band, usually in a segment reserved for contests
C	In the weak signal segment of the band, with most of the activity near the calling frequency
D	In the middle of each band, usually on the national calling frequency

11. - E2D04

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

Select	Answer
A	Doppler shift of beacon signals
B	APRS
C	Ultrasonics
D	Bandwidth compressed LORAN

12. - E2E01

Which of the following types of modulation is common for data emissions below 30 MHz?

Select	Answer
A	DTMF tones modulating an FM signal
B	Pulse modulation
C	FSK
D	Spread spectrum

13. - E3A11

What is a typical range for tropospheric propagation of microwave signals?

Select	Answer
A	2500 miles
B	10 miles to 50 miles
C	100 miles to 300 miles
D	1200 miles

14. - E3B06

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

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

15. - E3C03

Which of the following signal paths is most likely to experience high levels of absorption when the A index or K index is elevated?

Select	Answer
A	Transequatorial
B	Sporadic E
C	Polar
D	NVIS

16. - E4A05

What is the purpose of the prescaler function on a frequency counter?

Select	Answer
A	It multiplies a higher frequency signal so a low-frequency counter can display the operating frequency
B	It divides a higher frequency signal so a low-frequency counter can display the input frequency
C	It prevents oscillation in a low-frequency counter circuit
D	It amplifies low-level signals for more accurate counting

17. - E4B05

What three test loads are used to calibrate an RF vector network analyzer?

Select	Answer
A	Short circuit, open circuit, and 50 ohms
B	50 ohms through 1/8 wavelength, 1/4 wavelength, and 1/2 wavelength of coaxial cable
C	Short circuit, open circuit, and resonant circuit
D	50 ohms, 75 ohms, and 90 ohms

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 galactic noise contribution to minimum detectable signal
C	The theoretical noise in a 1 Hz bandwidth at the input of a perfect receiver at room temperature
D	The noise figure of a 1 Hz bandwidth receiver

19. - E4D08

What causes intermodulation in an electronic circuit?

Select	Answer
A	Positive feedback
B	Too little gain
C	Lack of neutralization
D	Nonlinear circuits or devices

20. - E4E05

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

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

21. - E5A03

What is the magnitude of the impedance of a series RLC circuit at resonance?

Select	Answer
A	Approximately equal to capacitive reactance
B	Approximately equal to inductive reactance
C	Approximately equal to circuit resistance
D	High, as compared to the circuit resistance

22. - E5B07

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 500 ohms, R is 1 kilohm, and XL is 250 ohms?

Select	Answer
A	14.0 degrees with the voltage lagging the current
B	68.2 degrees with the voltage lagging the current
C	68.2 degrees with the voltage leading the current
D	14.0 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 8
B	Point 7
C	Point 3
D	Point 1

24. - E5D03

What is microstrip?

Select	Answer
A	Short lengths of coax mounted on printed circuit boards to minimize time delay between microwave circuits
B	Miniature coax used for low power applications
C	Lightweight transmission line made of common zip cord
D	Precision printed circuit conductors above a ground plane that provide constant impedance interconnects at microwave frequencies

25. - E6A10

In Figure E6-1, what is the schematic symbol for an N-channel dual-gate MOSFET?

Select	Answer
A	2
B	4
C	5
D	6

26. - E6B01

What is the most useful characteristic of a Zener diode?

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

27. - E6C06

Why do CMOS digital integrated circuits have high immunity to noise on the input signal or power supply?

Select	Answer
A	Bandwidth is very limited
B	Large bypass capacitance is inherent
C	The input switching threshold is about one-half the power supply voltage
D	The input switching threshold is about two times the power supply voltage

28. - E6D08

What is one reason for using powdered-iron cores rather than ferrite cores in an inductor?

Select	Answer
A	Powdered-iron cores use smaller diameter wire for the same inductance
B	Powdered-iron cores generally have greater initial permeability
C	Powdered-iron cores generally require fewer turns to produce a given inductance
D	Powdered-iron cores generally maintain their characteristics at higher currents

29. - E6E07

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

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

30. - E6F05

Which describes an optical shaft encoder?

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

31. - E7A05

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

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

32. - E7B04

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

Select	Answer
A	Approximately halfway between saturation and cutoff
B	At a point where the bias resistor equals the load resistor
C	Where the load line intersects the voltage axis
D	At a point where the load line intersects the zero bias current curve

33. - E7C03

What advantage does a series-L Pi-L-network have over a series-L Pi-network for impedance matching between the final amplifier of a vacuum-tube transmitter and an antenna?

Select	Answer
A	Greater transformation range
B	Does not require a capacitor
C	Greater harmonic suppression
D	Higher efficiency

34. - E7D03

What device is typically used as a stable voltage reference in a linear voltage regulator?

Select	Answer
A	A Zener diode
B	A varactor diode
C	A tunnel diode
D	An SCR

35. - E7E03

What is a frequency discriminator stage in a FM receiver?

Select	Answer
A	A circuit for filtering two closely adjacent signals
B	A circuit for detecting FM signals
C	An FM generator circuit
D	An automatic band-switching circuit

36. - E7F10

What aspect of receiver analog-to-digital conversion determines the maximum receive bandwidth of a Direct Digital Conversion SDR?

Select	Answer
A	Processor latency
B	Sample width in bits
C	Sample clock phase noise
D	Sample rate

37. - E7G04

What is meant by the "op-amp input offset voltage"?

Select	Answer
A	The output voltage of the op-amp minus its input voltage
B	The differential input voltage needed to bring the open loop output voltage to zero
C	The potential between the amplifier input terminals of the op-amp in an open loop condition
D	The difference between the output voltage of the op-amp and the input voltage required in the immediately following stage

38. - E7H05

How is positive feedback supplied in a Pierce oscillator?

Select	Answer
A	Through link coupling
B	Through a neutralizing capacitor
C	Through a tapped coil
D	Through a quartz crystal

39. - E8A04

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

Select	Answer
A	A method of decimation by randomly skipping samples
B	A small amount of noise added to the input signal to allow more precise representation of a signal over time
C	An error caused by irregular quantization step size
D	An abnormal condition where the converter cannot settle on a value to represent the signal

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 data streams share the same channel by transmitting time of transmission as the sub-carrier
D	Two or more signals are quadrature modulated to increase bandwidth efficiency

41. - E8C09

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

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

42. - E8D07

What is a common cause of overmodulation of AFSK signals?

Select	Answer
A	Bit errors in the modem
B	Ground loops
C	Excessive transmit audio levels
D	Excessive numbers of retries

43. - E9A10

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

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

44. - E9B01

In the antenna radiation pattern shown in Figure E9-1, what is the beamwidth?

Select	Answer
A	30 degrees
B	50 degrees
C	75 degrees
D	25 degrees

45. - E9C06

What is the effect of adding a terminating resistor to a rhombic antenna?

Select	Answer
A	It changes the radiation pattern from bidirectional to unidirectional
B	It decreases the ground loss
C	It changes the radiation pattern from horizontal to vertical polarization
D	It reflects the standing waves on the antenna elements back to the transmitter

46. - E9D04

Why should an HF mobile antenna loading coil have a high ratio of reactance to resistance?

Select	Answer
A	To minimize losses
B	To minimize the Q
C	To lower the radiation angle
D	To swamp out harmonics

47. - E9E11

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

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

48. - E9F06

What is the approximate physical length of an air-insulated, parallel conductor transmission line that is electrically 1/2 wavelength long at 14.10 MHz?

Select	Answer
A	7.0 meters
B	10.6 meters
C	13.3 meters
D	8.5 meters

49. - E9G03

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

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

50. - E9H06

What is the triangulation method of direction finding?

Select	Answer
A	A fixed receiving station plots three headings to the signal source
B	A fixed receiving station uses three different antennas to plot the location of the signal source
C	Antenna headings from several different receiving locations are used to locate the signal source
D	The geometric angles of sky waves from the source are used to determine its position

Figure E5-1

Figure E6-1

Figure E9-1