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

2. - E1A06

Where must the carrier frequency of a CW signal be set to comply with FCC rules for 60 meter operation?

Select	Answer
A	At the lowest frequency of the channel
B	On any frequency where the signal's sidebands are within the channel
C	At the highest frequency of the channel
D	At the center frequency of the channel

3. - E1B05

What is the National Radio Quiet Zone?

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

4. - E1C04

What is meant by IARP?

Select	Answer
A	A forecast of intermittent aurora radio propagation
B	An international amateur radio permit that allows U.S. amateurs to operate in certain countries of the Americas
C	An indication of increased antenna reflected power
D	The internal amateur radio practices policy of the FCC

5. - E1D09

Which UHF amateur bands have frequencies authorized for space stations?

Select	Answer
A	70 cm only
B	70 cm and 33 cm
C	33 cm and 13 cm
D	70 cm and 13 cm

6. - E1E04

Which of the following best describes the Volunteer Examiner accreditation process?

Select	Answer
A	The prospective VE obtains accreditation from the FCC
B	The amateur operator applying must pass a VE examination administered by the FCC Enforcement Bureau
C	Each General, Advanced and Amateur Extra Class operator is automatically accredited as a VE when the license is granted
D	The procedure by which a VEC confirms that the VE applicant meets FCC requirements to serve as an examiner

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 transmitting station must be in an area regulated by the FCC or in a country that permits SS emissions
D	The transmission must not be used to obscure the meaning of any communication

8. - E2A09

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

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

9. - E2B02

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

Select	Answer
A	30
B	1080
C	525
D	60

10. - E2C07

What is the Cabrillo format?

Select	Answer
A	A standard for submission of electronic contest logs
B	The most common set of contest rules
C	A method of exchanging information during a contest QSO
D	The rules of order for meetings between contest sponsors

11. - E2D01

Which of the following digital modes is designed for meteor scatter communications?

Select	Answer
A	APRS
B	MSK144
C	Hellschreiber
D	WSPR

12. - E2E08

Which of the following HF digital modes can be used to transfer binary files?

Select	Answer
A	RTTY
B	Hellschreiber
C	PACTOR
D	AMTOR

13. - E3A10

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

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

14. - E3B03

What is the best time of day for transequatorial propagation?

Select	Answer
A	Morning
B	Afternoon or early evening
C	Late at night
D	Noon

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	Polar
B	Sporadic E
C	Transequatorial
D	NVIS

16. - E4A02

Which of the following parameters does a spectrum analyzer display on the vertical and horizontal axes?

Select	Answer
A	SWR and time
B	RF amplitude and time
C	SWR and frequency
D	RF amplitude and frequency

17. - E4B08

Which of the following can be used to measure the Q of a series-tuned circuit?

Select	Answer
A	The frequency shift
B	The resonant frequency of the circuit
C	The inductance to capacitance ratio
D	The bandwidth of the circuit's frequency response

18. - E4C11

Why can an attenuator be used to reduce receiver overload on the lower frequency HF bands with little or no impact on signal-to-noise ratio?

Select	Answer
A	Atmospheric noise is generally greater than internally generated noise even after attenuation
B	The attenuator has a noise filter to suppress interference
C	Signals are attenuated separately from the noise
D	The attenuator has a low-pass filter to increase the strength of lower frequency signals

19. - E4D12

What is the term for the reduction in receiver sensitivity caused by a strong signal near the received frequency?

Select	Answer
A	Squelch gain rollback
B	Cross-modulation interference
C	Quieting
D	Desensitization

20. - E4E03

Which of the following signals might a receiver noise blanker be able to remove from desired signals?

Select	Answer
A	Signals that appear at one IF but not another
B	Signals that are constant at all IF levels
C	Signals that have a sharply peaked frequency distribution
D	Signals that appear across a wide bandwidth

21. - E5A14

What is the resonant frequency of an RLC circuit if R is 22 ohms, L is 50 microhenries and C is 40 picofarads?

Select	Answer
A	1.78 MHz
B	44.72 MHz
C	22.36 MHz
D	3.56 MHz

22. - E5B09

What is the relationship between the AC current through a capacitor and the voltage across a capacitor?

Select	Answer
A	Voltage leads current by 90 degrees
B	Current leads voltage by 90 degrees
C	Voltage and current are in phase
D	Voltage and current are 180 degrees out of phase

23. - E5C03

Which of the following represents an inductive reactance in polar coordinates?

Select	Answer
A	A negative magnitude
B	A negative phase angle
C	A positive magnitude
D	A positive phase angle

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	Precision printed circuit conductors above a ground plane that provide constant impedance interconnects at microwave frequencies
C	Lightweight transmission line made of common zip cord
D	Miniature coax used for low power applications

25. - E6A02

Which of the following semiconductor materials contains excess free electrons?

Select	Answer
A	Insulated gate
B	P-type
C	Bipolar
D	N-type

26. - E6B10

In Figure E6-2, what is the schematic symbol for a light-emitting diode?

Select	Answer
A	5
B	6
C	1
D	7

27. - E6C07

What best describes a pull-up or pull-down resistor?

Select	Answer
A	A resistor that ensures that an oscillator frequency does not drift
B	A resistor connected to the positive or negative supply line used to establish a voltage when an input or output is an open circuit
C	A resistor connected to an op-amp output that prevents signals from exceeding the power supply voltage
D	A resistor in a keying circuit used to reduce key clicks

28. - E6D09

What devices are commonly used as VHF and UHF parasitic suppressors at the input and output terminals of a transistor HF amplifier?

Select	Answer
A	Butterworth filters
B	Steel-core toroids
C	Ferrite beads
D	Electrolytic capacitors

29. - E6E08

How is power supplied to the most common type of MMIC?

Select	Answer
A	Through a resistor and/or RF choke connected to the amplifier output lead
B	MMICs require no operating bias
C	Directly to the bias voltage (VCC IN) lead
D	Through a capacitor and RF choke connected to the amplifier input lead

30. - E6F08

Why are optoisolators often used in conjunction with solid-state circuits when switching 120 VAC?

Select	Answer
A	Optoisolators eliminate the effects of reflected light in the control circuit
B	Optoisolators provide a very high degree of electrical isolation between a control circuit and the circuit being switched
C	Optoisolators provide impedance matching between the control circuit and power circuit
D	Optoisolators provide a low impedance link between a control circuit and a power circuit

31. - E7A02

What is the function of a decade counter?

Select	Answer
A	It decodes a decimal number for display on a seven-segment LED display
B	It produces 10 output pulses for every input pulse
C	It produces one output pulse for every 10 input pulses
D	It decodes a binary number for display on a seven-segment LED display

32. - E7B03

Which of the following components form the output of a class D amplifier circuit?

Select	Answer
A	A high-pass filter to compensate for low gain at low frequencies
B	A low-pass filter to remove switching signal components
C	A matched load resistor to prevent damage by switching transients
D	A temperature compensating load resistor to improve linearity

33. - E7C04

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

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

34. - E7D02

What is a characteristic of a switching electronic voltage regulator?

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

35. - E7E03

What is a frequency discriminator stage in a FM receiver?

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

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	Software is converted from source code to object code during operation of the receiver
C	A switching mixer is used to generate I and Q signals directly from the RF input
D	Incoming RF is converted to a control voltage for a voltage controlled oscillator

37. - E7G02

What is ringing in a filter?

Select	Answer
A	Partial cancellation of the signal over a range of frequencies
B	An echo caused by a long time delay
C	A reduction in high frequency response
D	Undesired oscillations added to the desired signal

38. - E7H01

What are three oscillator circuits used in amateur radio equipment?

Select	Answer
A	Pierce, Fenner and Beane
B	Taft, Hartley and Pierce
C	Colpitts, Hartley and Pierce
D	Taft, Pierce and negative feedback

39. - E8A01

What is the name of the process that shows that a square wave is made up of a sine wave plus all its odd harmonics?

Select	Answer
A	Differential analysis
B	Fourier analysis
C	Vector analysis
D	Numerical analysis

40. - E8B10

What is frequency division multiplexing?

Select	Answer
A	The transmitted signal is divided into packets of information
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 jumps from band to band at a predetermined rate

41. - E8C07

What is the bandwidth of a 4800-Hz frequency shift, 9600-baud ASCII FM transmission?

Select	Answer
A	4.8 kHz
B	5.76 kHz
C	9.6 kHz
D	15.36 kHz

42. - E8D05

What is the most common method of reducing key clicks?

Select	Answer
A	Reduce keying waveform rise and fall times
B	High-pass filters at the transmitter output
C	Increase keying waveform rise and fall times
D	Low-pass filters at the transmitter output

43. - E9A13

What term describes station output, taking into account all gains and losses?

Select	Answer
A	Effective radiated power
B	Half-power bandwidth
C	Power factor
D	Apparent power

44. - E9B10

What is the principle of a Method of Moments analysis?

Select	Answer
A	A wire is modeled as a single sine-wave voltage source
B	A wire is modeled as a series of segments, each having a distinct value of voltage across it
C	A wire is modeled as a single sine-wave current generator
D	A wire is modeled as a series of segments, each having a uniform value of current

45. - E9C01

What is the radiation pattern of two 1/4-wavelength vertical antennas spaced 1/2-wavelength apart and fed 180 degrees out of phase?

Select	Answer
A	A figure-8 broadside to the axis of the array
B	Cardioid
C	Omni-directional
D	A figure-8 oriented along the axis of the array

46. - E9D09

What is the function of a loading coil used as part of an HF mobile antenna?

Select	Answer
A	To increase the SWR bandwidth
B	To lower the losses
C	To lower the Q
D	To cancel capacitive reactance

47. - E9E06

Which of these feed line impedances would be suitable for constructing a quarter-wave Q-section for matching a 100-ohm loop to 50-ohm feed line?

Select	Answer
A	62 ohms
B	50 ohms
C	75 ohms
D	450 ohms

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	3.5 meters
B	5.3 meters
C	10.6 meters
D	4.3 meters

49. - E9G02

What type of coordinate system is used in a Smith chart?

Select	Answer
A	Resistance lines and reactance chords
B	Voltage circles and current arcs
C	Voltage lines and current chords
D	Resistance circles and reactance arcs

50. - E9H10

How can the output voltage of a multiple-turn receiving loop antenna be increased?

Select	Answer
A	By increasing the number of turns and/or the area
B	By utilizing high impedance wire for the coupling loop
C	By winding adjacent turns in opposing directions
D	By reducing the permeability of the loop shield

Figure E6-2