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

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1. - E0A10

What toxic material may be present in some electronic components such as high voltage capacitors and transformers?

Select	Answer
A	Polychlorinated biphenyls
B	Polytetrafluoroethylene
C	Polymorphic silicon
D	Polyethylene

2. - E1A05

What is the maximum power output permitted on the 60 meter band?

Select	Answer
A	50 watts PEP effective radiated power relative to an isotropic radiator
B	100 watts PEP effective radiated power relative to an isotropic radiator
C	100 watts PEP effective radiated power relative to the gain of a half-wave dipole
D	50 watts PEP effective radiated power relative to a dipole

3. - E1B05

What is the National Radio Quiet Zone?

Select	Answer
A	An area in Florida surrounding Cape Canaveral
B	An area surrounding the National Radio Astronomy Observatory
C	An area in Puerto Rico surrounding the Arecibo Radio Telescope
D	An area in New Mexico surrounding the White Sands Test Area

4. - E1C12

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

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

5. - E1D01

What is the definition of telemetry?

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

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 collect and send the documents to the FCC according to instructions
D	They must submit the application document to the coordinating VEC according to the coordinating VEC instructions

7. - E1F06

Under what circumstances might the FCC issue a Special Temporary Authority (STA) to an amateur station?

Select	Answer
A	To allow regular operation on Land Mobile channels
B	To provide for experimental amateur communications
C	To provide additional spectrum for personal use
D	To provide temporary operation while awaiting normal licensing

8. - E2A08

Why should effective radiated power to a satellite that uses a linear transponder be limited?

Select	Answer
A	To avoid interfering with terrestrial QSOs
B	To prevent the satellite from emitting out-of-band signals
C	To avoid reducing the downlink power to all other users
D	To prevent creating errors in the satellite telemetry

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	No other hardware is needed
C	A special IF converter
D	A special notch filter to remove synchronization pulses

10. - E2C01

What indicator is required to be used by U.S.-licensed operators when operating a station via remote control and the remote transmitter is located in the U.S.?

Select	Answer
A	/R# where # is the district of the remote station
B	/ followed by the ARRL Section of the remote station
C	/ followed by the USPS two-letter abbreviation for the state in which the remote station is located
D	No additional indicator is required

11. - E2D07

What digital protocol is used by APRS?

Select	Answer
A	802.11
B	PACTOR
C	AMTOR
D	AX.25

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

13. - E3A14

What is meant by circularly polarized electromagnetic waves?

Select	Answer
A	Waves with an electric field bent into a circular shape
B	Waves with a rotating electric field
C	Waves that circle the Earth
D	Waves produced by a loop antenna

14. - E3B07

What happens to linearly polarized radio waves that split into ordinary and extraordinary waves in the ionosphere?

Select	Answer
A	They become elliptically polarized
B	They become phase locked
C	They are bent toward the magnetic poles
D	They become depolarized

15. - E3C02

What is indicated by a rising A or K index?

Select	Answer
A	Higher levels of solar UV radiation
B	Increasing disruption of the geomagnetic field
C	An increase in the critical frequency
D	Decreasing disruption of the geomagnetic field

16. - E4A04

How is the compensation of an oscilloscope probe typically adjusted?

Select	Answer
A	A square wave is displayed and the probe is adjusted until the horizontal portions of the displayed wave are as nearly flat as possible
B	A high frequency sine wave is displayed and the probe is adjusted for maximum amplitude
C	A frequency standard is displayed and the probe is adjusted until the deflection time is accurate
D	A DC voltage standard is displayed and the probe is adjusted until the displayed voltage is accurate

17. - E4B06

How much power is being absorbed by the load when a directional power meter connected between a transmitter and a terminating load reads 100 watts forward power and 25 watts reflected power?

Select	Answer
A	75 watts
B	100 watts
C	125 watts
D	25 watts

18. - E4C02

Which of the following receiver circuits can be effective in eliminating interference from strong out-of-band signals?

Select	Answer
A	A properly adjusted product detector
B	A notch filter
C	A front-end filter or pre-selector
D	A narrow IF filter

19. - E4D02

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

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

20. - E4E04

How can conducted and radiated noise caused by an automobile alternator be suppressed?

Select	Answer
A	By connecting the radio's power leads directly to the battery and by installing coaxial capacitors in line with the alternator leads
B	By installing filter capacitors in series with the DC power lead and a blocking capacitor in the field lead
C	By installing a high-pass filter in series with the radio's power lead and a low-pass filter in parallel with the field lead
D	By installing a noise suppression resistor and a blocking capacitor in both leads

21. - E5A07

What is the magnitude of the current at the input of a parallel RLC circuit at resonance?

Select	Answer
A	R/L
B	L/R
C	Minimum
D	Maximum

22. - E5B01

What is the term for the time required for the capacitor in an RC circuit to be charged to 63.2% of the applied voltage or to discharge to 36.8% of its initial voltage?

Select	Answer
A	A time factor of one
B	One exponential period
C	One time constant
D	An exponential rate of one

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. - E5D03

What is microstrip?

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

25. - E6A09

What is a depletion-mode FET?

Select	Answer
A	An FET that has no current flow between source and drain when no gate voltage is applied
B	An FET that exhibits a current flow between source and drain when no gate voltage is applied
C	Any FET without a channel
D	Any FET for which holes are the majority carriers

26. - E6B11

What is used to control the attenuation of RF signals by a PIN diode?

Select	Answer
A	Capacitance of an RF coupling capacitor
B	A sub-harmonic pump signal
C	Forward DC bias current
D	Reverse voltage larger than the RF signal

27. - E6C05

What is an advantage of CMOS logic devices over TTL devices?

Select	Answer
A	Immune to damage from static discharge
B	Lower power consumption
C	Lower distortion
D	Differential output capability

28. - E6D10

What is a primary advantage of using a toroidal core instead of a solenoidal core in an inductor?

Select	Answer
A	Toroidal cores confine most of the magnetic field within the core material
B	Toroidal cores have lower Q characteristics
C	Toroidal cores make it easier to couple the magnetic energy into other components
D	Toroidal cores exhibit greater hysteresis

29. - E6E04

Which is the most common input and output impedance of circuits that use MMICs?

Select	Answer
A	300 ohms
B	10 ohms
C	50 ohms
D	450 ohms

30. - E6F07

What is a solid-state relay?

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

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	Monostable multivibrator
C	Astable multivibrator
D	T flip-flop

32. - E7B12

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

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

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

34. - E7D13

What is the equation for calculating power dissipated by a series linear voltage regulator?

Select	Answer
A	Input voltage divided by output current
B	Input voltage multiplied by input current
C	Output voltage multiplied by output current
D	Voltage difference from input to output multiplied by output current

35. - E7E02

What is the function of a reactance modulator?

Select	Answer
A	To produce AM signals by using an electrically variable resistance
B	To produce PM signals by using an electrically variable resistance
C	To produce AM signals by using an electrically variable inductance or capacitance
D	To produce PM or FM signals by using an electrically variable inductance or capacitance

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 clock phase noise
C	Sample width in bits
D	Sample rate

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	76
B	1
C	0.03
D	38

38. - E7H02

What is a microphonic?

Select	Answer
A	Excess loading of the microphone by an oscillator
B	Changes in oscillator frequency due to mechanical vibration
C	Distortion caused by RF pickup on the microphone cable
D	An IC used for amplifying microphone signals

39. - E8A09

How many different input levels can be encoded by an analog-to-digital converter with 8-bit resolution?

Select	Answer
A	8 multiplied by the gain of the input amplifier
B	8
C	256 divided by the gain of the input amplifier
D	256

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 increases as the RF carrier frequency increases
C	It does not depend on the RF carrier frequency
D	It varies with the square root of the RF carrier frequency

41. - E8C04

What technique minimizes the bandwidth of a PSK31 signal?

Select	Answer
A	Zero-sum character encoding
B	Use of trapezoidal data pulses
C	Use of sinusoidal data pulses
D	Reed-Solomon character encoding

42. - E8D06

What is the advantage of including parity bits in ASCII characters?

Select	Answer
A	Foreign language characters can be sent
B	Faster transmission rate
C	The signal can overpower interfering signals
D	Some types of errors can be detected

43. - E9A10

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

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

44. - E9B01

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

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

45. - E9C06

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

Select	Answer
A	It decreases the ground loss
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 changes the radiation pattern from horizontal to vertical polarization

46. - E9D10

What happens to feed-point impedance at the base of a fixed length HF mobile antenna when operated below its resonant frequency?

Select	Answer
A	The radiation resistance increases and the capacitive reactance decreases
B	The radiation resistance increases and the capacitive reactance increases
C	The radiation resistance decreases and the capacitive reactance increases
D	The radiation resistance decreases and the capacitive reactance decreases

47. - E9E08

What is a use for a Wilkinson divider?

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

48. - E9F13

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

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

49. - E9G05

Which of the following is a common use for a Smith chart?

Select	Answer
A	Determine the loss/100 feet of a transmission line, given the velocity factor and conductor materials
B	Determine the impedance of a transmission line, given the physical dimensions
C	Determine the length and position of an impedance matching stub
D	Determine the gain of an antenna given the physical and electrical parameters

50. - E9H11

What feature of a cardioid pattern antenna makes it useful for direction finding?

Select	Answer
A	Broadband response
B	A very sharp peak
C	High radiation angle
D	A very sharp single null

Figure E7-1

Figure E7-3

Figure E9-1