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

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1. - E0A11

Which of the following injuries can result from using high-power UHF or microwave transmitters?

Select	Answer
A	Hearing loss caused by high voltage corona discharge
B	Blood clotting from the intense magnetic field
C	Ingestion of ozone gas from the cooling system
D	Localized heating of the body from RF exposure in excess of the MPE limits

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	1 watt EIRP
C	5 watts EIRP
D	100 watts PEP

3. - E1B07

To what type of regulations does PRB-1 apply?

Select	Answer
A	FAA tower height limits
B	Use of wireless devices in vehicles
C	Homeowners associations
D	State and local zoning

4. - E1C01

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

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

5. - E1D03

What is a space telecommand station?

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

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

7. - E1F09

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

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

8. - E2A06

What are Keplerian elements?

Select	Answer
A	Encrypting codes used for spread spectrum modulation
B	Parameters that define the orbit of a satellite
C	Phase reversing elements in a Yagi antenna
D	High-emission heater filaments used in magnetron tubes

9. - E2B12

What signals SSTV receiving software to begin a new picture line?

Select	Answer
A	Specific tone frequencies
B	Specific tone amplitudes
C	A two-tone signal
D	Elapsed time

10. - E2C05

What is the function of a DX QSL Manager?

Select	Answer
A	To allocate frequencies for DXpeditions
B	To relay calls to and from a DX station
C	To handle the receiving and sending of confirmation cards for a DX station
D	To run a net to allow many stations to contact a rare DX station

11. - E2D02

Which of the following is a good technique for making meteor scatter contacts?

Select	Answer
A	All these choices are correct
B	15-second timed transmission sequences with stations alternating based on location
C	Short transmissions with rapidly repeated call signs and signal reports
D	Use of special digital modes

12. - E2E10

Which of these digital modes has the narrowest bandwidth?

Select	Answer
A	PSK31
B	MFSK16
C	300-baud packet
D	170 Hz shift, 45-baud RTTY

13. - E3A10

Which type of atmospheric structure can create a path for microwave propagation?

Select	Answer
A	Wind shear
B	Temperature inversion
C	Dust devil
D	The jet stream

14. - E3B12

What is the primary characteristic of chordal hop propagation?

Select	Answer
A	Propagation away from the great circle bearing between stations
B	Successive ionospheric refractions without an intermediate reflection from the ground
C	Propagation across the geomagnetic equator
D	Signals reflected back toward the transmitting station

15. - E3C11

What does VOACAP software model?

Select	Answer
A	AC current and impedance
B	VHF radio propagation
C	AC voltage and impedance
D	HF propagation

16. - E4A08

Which of the following measures SWR?

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

17. - E4B03

Which S parameter is equivalent to forward gain?

Select	Answer
A	S22
B	S11
C	S12
D	S21

18. - E4C08

An SDR receiver is overloaded when input signals exceed what level?

Select	Answer
A	One-half the maximum sample rate
B	One-half the maximum sampling buffer size
C	The maximum count value of the analog-to-digital converter
D	The reference voltage of the analog-to-digital converter

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. - E4E08

What current flows equally on all conductors of an unshielded multi-conductor cable?

Select	Answer
A	Common-mode current
B	Differential-mode current
C	Reactive current only
D	Return current

21. - E5A10

How is the Q of an RLC series resonant circuit calculated?

Select	Answer
A	Reactance of either the inductance or capacitance multiplied by the resistance
B	Reactance of either the inductance or capacitance divided by the resistance
C	Resistance divided by the reactance of either the inductance or capacitance
D	Reactance of the inductance multiplied by the reactance of the capacitance

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	68.2 degrees with the voltage lagging the current
B	68.2 degrees with the voltage leading the current
C	14.0 degrees with the voltage lagging the current
D	14.0 degrees with the voltage leading the current

23. - E5C12

Which point on Figure E5-1 best represents the impedance of a series circuit consisting of a 300-ohm resistor and a 19-picofarad capacitor at 21.200 MHz?

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

24. - E5D04

Why are short connections used at microwave frequencies?

Select	Answer
A	To increase neutralizing resistance
B	To increase compensating capacitance
C	To reduce phase shift along the connection
D	To reduce noise figure

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 variable capacitance in an automatic frequency control circuit
C	As a constant voltage reference in a power supply
D	As a VHF/UHF mixer or detector

27. - E6C11

In Figure E6-3, what is the schematic symbol for the NOT operation (inverter)?

Select	Answer
A	4
B	2
C	5
D	6

28. - E6D07

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

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

29. - E6E11

What is a characteristic of DIP packaging used for integrated circuits?

Select	Answer
A	Two chips in each package (Dual In Package)
B	A total of two rows of connecting pins placed on opposite sides of the package (Dual In-line Package)
C	Low leakage doubly insulated package
D	Package mounts in a direct inverted position

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. - E7A09

What logical operation is performed by an exclusive NOR gate?

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

32. - E7B07

Which of the following is a likely result when a Class C amplifier is used to amplify a single-sideband phone signal?

Select	Answer
A	Signal distortion and excessive bandwidth
B	Reduced intermodulation products
C	Increased overall intelligibility
D	Signal inversion

33. - E7C04

How does an impedance-matching circuit transform a complex impedance to a resistive impedance?

Select	Answer
A	It introduces negative resistance to cancel the resistive part of impedance
B	It introduces transconductance to cancel the reactive part of impedance
C	Reactive currents are dissipated in matched resistances
D	It cancels the reactive part of the impedance and changes the resistive part to a desired value

34. - E7D15

What is the purpose of a step-start circuit in a high-voltage power supply?

Select	Answer
A	To provide a dual-voltage output for reduced power applications
B	To allow for remote control of the power supply
C	To allow the filter capacitors to charge gradually
D	To compensate for variations of the incoming line voltage

35. - E7E11

Which type of detector circuit is used for demodulating SSB signals?

Select	Answer
A	Discriminator
B	Product detector
C	Phase detector
D	Phase comparator

36. - E7F01

What is meant by direct digital conversion as applied to software defined radios?

Select	Answer
A	Incoming RF is digitized by an analog-to-digital converter without being mixed with a local oscillator signal
B	Incoming RF is converted to a control voltage for a voltage controlled oscillator
C	Software is converted from source code to object code during operation of the receiver
D	A switching mixer is used to generate I and Q signals directly from the RF input

37. - E7G01

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

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

38. - E7H14

What is a phase-locked loop circuit?

Select	Answer
A	An electronic servo loop consisting of a ratio detector, reactance modulator, and voltage-controlled oscillator
B	An electronic circuit also known as a monostable multivibrator
C	An electronic circuit consisting of a precision push-pull amplifier with a differential input
D	An electronic servo loop consisting of a phase detector, a low-pass filter, a voltage-controlled oscillator, and a stable reference oscillator

39. - E8A06

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

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

40. - E8B10

What is frequency division multiplexing?

Select	Answer
A	The transmitted signal jumps from band to band at a predetermined rate
B	Two or more information streams are merged into a baseband, which then modulates the transmitter
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. - E8C06

What is the bandwidth of a 170-hertz shift, 300-baud ASCII transmission?

Select	Answer
A	0.3 kHz
B	1.0 kHz
C	0.1 Hz
D	0.5 kHz

42. - E8D11

What is one advantage of using ASCII code for data communications?

Select	Answer
A	It uses one character as a shift code to send numeric and special characters
B	It is possible to transmit both upper and lower case text
C	It contains fewer information bits per character than any other code
D	It includes built-in error correction features

43. - E9A05

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

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

44. - E9B09

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

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

45. - E9C06

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

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

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 swamp out harmonics
C	To minimize the Q
D	To lower the radiation angle

47. - E9E08

What is a use for a Wilkinson divider?

Select	Answer
A	It divides the operating frequency of a transmitter signal so it can be used on a lower frequency band
B	It is used to feed high-impedance antennas from a low-impedance source
C	It is used to feed low-impedance loads from a high-impedance source
D	It is used to divide power equally between two 50-ohm loads while maintaining 50-ohm input impedance

48. - E9F05

What is the approximate physical length of a solid polyethylene dielectric coaxial transmission line that is electrically 1/4 wavelength long at 14.1 MHz?

Select	Answer
A	10.6 meters
B	3.5 meters
C	5.3 meters
D	4.3 meters

49. - E9G03

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

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

50. - E9H08

What is the function of a sense antenna?

Select	Answer
A	It provides diversity reception that cancels multipath signals
B	It increases the sensitivity of a DF antenna array
C	It allows DF antennas to receive signals at different vertical angles
D	It modifies the pattern of a DF antenna array to provide a null in one direction

Figure E5-1

Figure E6-3