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

Logging in (or registering) will help the system to select questions that you need to focus on.

1. - E0A08

What does SAR measure?

Select	Answer
A	The rate of RF energy reflected from stationary terrain
B	The rate at which RF energy is absorbed by the body
C	Signal Amplification Rating
D	Synthetic Aperture Ratio of the human body

2. - E1A12

What special operating frequency restrictions are imposed on slow scan TV transmissions?

Select	Answer
A	None; they are allowed on all amateur frequencies
B	They are restricted to 7.245 MHz, 14.245 MHz, 21.345 MHz, and 28.945 MHz
C	They are not permitted above 54 MHz
D	They are restricted to phone band segments

3. - E1B05

What is the National Radio Quiet Zone?

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

4. - E1C11

Which of the following operating arrangements allows an FCC-licensed U.S. citizen to operate in many European countries, and alien amateurs from many European countries to operate in the U.S.?

Select	Answer
A	ITU reciprocal license
B	IARP agreement
C	All these choices are correct
D	CEPT agreement

5. - E1D09

Which UHF amateur bands have frequencies authorized for space stations?

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

6. - E1E04

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

Select	Answer
A	The amateur operator applying must pass a VE examination administered by the FCC Enforcement Bureau
B	The prospective VE obtains accreditation from the FCC
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. - E1F04

Which of the following geographic descriptions approximately describes "Line A"?

Select	Answer
A	A line roughly parallel to and south of the border between the U.S. and Canada
B	A line roughly parallel to and north of the border between the U.S. and Mexico
C	A line roughly parallel to and east of the U.S. Pacific coastline
D	A line roughly parallel to and west of the U.S. Atlantic coastline

8. - E2A10

What type of satellite appears to stay in one position in the sky?

Select	Answer
A	Geomagnetic
B	HEO
C	Geostationary
D	LEO

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

10. - E2C10

Why might a DX station state that they are listening on another frequency?

Select	Answer
A	All these choices are correct
B	Because the DX station may be transmitting on a frequency that is prohibited to some responding stations
C	To separate the calling stations from the DX station
D	To improve operating efficiency by reducing interference

11. - E2D01

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

Select	Answer
A	Hellschreiber
B	WSPR
C	APRS
D	MSK144

12. - E2E08

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

Select	Answer
A	Hellschreiber
B	AMTOR
C	RTTY
D	PACTOR

13. - E3A04

What do Hepburn maps predict?

Select	Answer
A	Sporadic E propagation
B	Locations of auroral reflecting zones
C	Likelihood of rain scatter along cold or warm fronts
D	Probability of tropospheric propagation

14. - E3B10

Why is chordal hop propagation desirable?

Select	Answer
A	The MUF for chordal hop propagation is much lower than for normal skip propagation
B	Signals travel faster along ionospheric chords
C	Atmospheric noise is lower in the direction of chordal hop propagation
D	The signal experiences less loss compared to multi-hop using Earth as a reflector

15. - E3C11

What does VOACAP software model?

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

16. - E4A07

Which of the following is an advantage of using an antenna analyzer compared to an SWR bridge to measure antenna SWR?

Select	Answer
A	Antenna analyzers automatically tune your antenna for resonance
B	Antenna analyzers display a time-varying representation of the modulation envelope
C	All these choices are correct
D	Antenna analyzers do not need an external RF source

17. - E4B08

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

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

18. - E4C07

What does the MDS of a receiver represent?

Select	Answer
A	The maximum detectable spectrum
B	The minimum discernible signal
C	The multiplex distortion stability
D	The meter display sensitivity

19. - E4D07

Which of the following reduces the likelihood of receiver desensitization?

Select	Answer
A	Switch from fast AGC to slow AGC
B	Raise the receiver IF frequency
C	Increase the receiver front end gain
D	Decrease the RF bandwidth of the receiver

20. - E4E01

What problem can occur when using an automatic notch filter (ANF) to remove interfering carriers while receiving CW signals?

Select	Answer
A	Any nearby signal passing through the DSP system will overwhelm the desired signal
B	Removal of the CW signal as well as the interfering carrier
C	Ringing in the DSP filter will completely remove the spaces between the CW characters
D	Received CW signals will appear to be modulated at the DSP clock frequency

21. - E5A11

What is the half-power bandwidth of a resonant circuit that has a resonant frequency of 7.1 MHz and a Q of 150?

Select	Answer
A	47.3 kHz
B	23.67 kHz
C	315.6 Hz
D	157.8 Hz

22. - E5B05

What happens to the magnitude of a pure reactance when it is converted to a susceptance?

Select	Answer
A	It is shifted by 90 degrees
B	It becomes the reciprocal
C	It is unchanged
D	The sign is reversed

23. - E5C07

Where is the impedance of a pure resistance plotted on rectangular coordinates?

Select	Answer
A	On the horizontal axis
B	On the vertical axis
C	On a line through the origin, slanted at 45 degrees
D	On a horizontal line, offset vertically above the horizontal axis

24. - E5D15

What is the power factor of an RL circuit having a 45-degree phase angle between the voltage and the current?

Select	Answer
A	0.707
B	1.0
C	0.866
D	0.5

25. - E6A03

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

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

27. - E6C03

What is tri-state logic?

Select	Answer
A	Logic devices with 0, 1, and high-impedance output states
B	Proprietary logic devices manufactured by Tri-State Devices
C	Low-power logic devices designed to operate at 3 volts
D	Logic devices that utilize ternary math

28. - E6D04

Which materials are commonly used as a core in an inductor?

Select	Answer
A	Ferrite and brass
B	Teflon and Delrin
C	Polystyrene and polyethylene
D	Cobalt and aluminum

29. - E6E04

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

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

30. - E6F01

What absorbs the energy from light falling on a photovoltaic cell?

Select	Answer
A	Protons
B	Holes
C	Electrons
D	Photons

31. - E7A01

Which circuit is bistable?

Select	Answer
A	A flip-flop
B	A bipolar amplifier
C	An OR gate
D	An AND gate

32. - E7B02

What is a Class D amplifier?

Select	Answer
A	A low power amplifier that uses a differential amplifier for improved linearity
B	An amplifier that uses drift-mode FETs for high efficiency
C	A frequency doubling amplifier
D	A type of amplifier that uses switching technology to achieve high efficiency

33. - E7C04

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

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

34. - E7D06

What is the purpose of Q1 in the circuit shown in Figure E7-2?

Select	Answer
A	It provides a constant load for the voltage source
B	It provides D1 with current
C	It provides negative feedback to improve regulation
D	It controls the current supplied to the load

35. - E7E04

What is one way a single-sideband phone signal can be generated?

Select	Answer
A	By using a balanced modulator followed by a filter
B	By using a loop modulator followed by a mixer
C	By using a reactance modulator followed by a mixer
D	By driving a product detector with a DSB signal

36. - E7F05

How frequently must an analog signal be sampled by an analog-to-digital converter so that the signal can be accurately reproduced?

Select	Answer
A	At the same rate as the highest frequency component of the signal
B	At four times the rate of the highest frequency component of the signal
C	At least twice the rate of the highest frequency component of the signal
D	At least half the rate of the highest frequency component of the signal

37. - E7G01

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

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

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

39. - E8A09

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

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

40. - E8B09

What is deviation ratio?

Select	Answer
A	The ratio of the highest audio modulating frequency to the average audio modulating frequency
B	The ratio of the carrier center frequency to the audio modulating frequency
C	The ratio of the audio modulating frequency to the center carrier frequency
D	The ratio of the maximum carrier frequency deviation to the highest audio modulating frequency

41. - E8C04

What technique minimizes the bandwidth of a PSK31 signal?

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

42. - E8D02

What spread spectrum communications technique uses a high-speed binary bit stream to shift the phase of an RF carrier?

Select	Answer
A	Binary phase-shift keying
B	Phase compandored spread spectrum
C	Frequency hopping
D	Direct sequence

43. - E9A04

Which of the following factors affect the feed point impedance of an antenna?

Select	Answer
A	Transmission line length
B	The input power level
C	The settings of an antenna tuner at the transmitter
D	Antenna height

44. - E9B10

What is the principle of a Method of Moments analysis?

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

45. - E9C12

Which of the following describes an Extended Double Zepp antenna?

Select	Answer
A	A center-fed 1.25-wavelength antenna (two 5/8-wave elements in phase)
B	An end-fed folded dipole antenna
C	A portable antenna erected using two push support poles
D	A wideband vertical antenna constructed from precisely tapered aluminum tubing

46. - E9D08

What happens as the Q of an antenna increases?

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

47. - E9E05

How must an antenna's driven element be tuned to use a hairpin matching system?

Select	Answer
A	The driven element radiation resistance must be higher than the characteristic impedance of the transmission line
B	The driven element reactance must be inductive
C	The driven element reactance must be capacitive
D	The driven element resonance must be lower than the operating frequency

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

49. - E9G02

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

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

50. - E9H07

Why is RF attenuation used when direction-finding?

Select	Answer
A	To increase receiver sensitivity
B	To prevent receiver overload which reduces pattern nulls
C	To compensate for isotropic directivity and the antenna effect of feed lines
D	To narrow the receiver bandwidth

Figure E7-2