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

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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	Synthetic Aperture Ratio of the human body
D	Signal Amplification Rating

2. - E1A03

What is the maximum legal carrier frequency on the 20 meter band for transmitting USB AFSK digital signals having a 1 kHz bandwidth?

Select	Answer
A	14.070 MHz
B	14.349 MHz
C	14.149 MHz
D	14.100 MHz

3. - E1B11

What does PRB-1 require of regulations affecting amateur radio?

Select	Answer
A	Use of wireless devices in a vehicle is exempt from regulation
B	Amateur radio operations must be permitted in any private residence
C	No limitations may be placed on antenna size or placement
D	Reasonable accommodations of amateur radio must be made

4. - E1C03

How do the control operator responsibilities of a station under automatic control differ from one under local control?

Select	Answer
A	Under local control a control operator is not required to be present at a control point
B	Under automatic control there is no control operator
C	Under local control there is no control operator
D	Under automatic control the control operator is not required to be present at the control point

5. - E1D02

Which of the following may transmit special codes intended to obscure the meaning of messages?

Select	Answer
A	Auxiliary relay links carrying repeater audio
B	Binary control characters
C	Telecommand signals from a space telecommand station
D	Data containing personal information

6. - E1E08

To which of the following examinees may a VE not administer an examination?

Select	Answer
A	Friends of the VE
B	Employees of the VE
C	All these choices are correct
D	Relatives of the VE as listed in the FCC rules

7. - E1F11

Which of the following best describes one of the standards that must be met by an external RF power amplifier if it is to qualify for a grant of FCC certification?

Select	Answer
A	It must produce full legal output when driven by not more than 5 watts of mean RF input power
B	It must exhibit a gain of 0 dB or less over its full output range
C	It must be capable of external RF switching between its input and output networks
D	It must satisfy the FCC's spurious emission standards when operated at the lesser of 1500 watts or its full output power

8. - E2A04

What is meant by the term mode? as applied to an amateur radio satellite?

Select	Answer
A	The satellite's orientation with respect to the Earth
B	The satellite's uplink and downlink frequency bands
C	Whether the satellite is in a polar or equatorial orbit
D	Whether the satellite is in a low earth or geostationary orbit

9. - E2B08

What technique allows commercial analog TV receivers to be used for fast-scan TV operations on the 70 cm band?

Select	Answer
A	Transmitting on channels shared with cable TV
B	Transmitting on the abandoned TV channel 2
C	Using USB and demodulating the signal with a computer sound card
D	Using converted satellite TV dishes

10. - E2C05

What is the function of a DX QSL Manager?

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

11. - E2D11

Which of the following data are used by the APRS network to communicate station location?

Select	Answer
A	Polar coordinates
B	Radio direction finding spectrum analysis
C	Time and frequency
D	Latitude and longitude

12. - E2E04

What is indicated when one of the ellipses in an FSK crossed-ellipse display suddenly disappears?

Select	Answer
A	The receiver has drifted 5 kHz from the desired receive frequency
B	Selective fading has occurred
C	The mark and space signal have been inverted
D	One of the signal filters is saturated

13. - E3A06

What might help to restore contact when DX signals become too weak to copy across an entire HF band a few hours after sunset?

Select	Answer
A	Wait 90 minutes or so for the signal degradation to pass
B	Wait 24 hours before attempting another communication on the band
C	Switch to a lower frequency HF band
D	Switch to a higher frequency HF band

14. - E3B02

What is the approximate maximum range for signals using transequatorial propagation?

Select	Answer
A	5000 miles
B	1000 miles
C	7500 miles
D	2500 miles

15. - E3C02

What is indicated by a rising A or K index?

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

16. - E4A09

Which of the following is good practice when using an oscilloscope probe?

Select	Answer
A	Never use a high-impedance probe to measure a low-impedance circuit
B	Never use a DC-coupled probe to measure an AC circuit
C	All these choices are correct
D	Keep the signal ground connection of the probe as short as possible

17. - E4B01

Which of the following factors most affects the accuracy of a frequency counter?

Select	Answer
A	Time base accuracy
B	Decade divider accuracy
C	Temperature coefficient of the logic
D	Input attenuator accuracy

18. - E4C02

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

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

19. - E4D08

What causes intermodulation in an electronic circuit?

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

20. - E4E07

Which of the following can cause shielded cables to radiate or receive interference?

Select	Answer
A	Use of braided shielding material
B	Tying all ground connections to a common point resulting in differential-mode currents in the shield
C	Low inductance ground connections at both ends of the shield
D	Common-mode currents on the shield and conductors

21. - E5A10

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

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

22. - E5B12

What is admittance?

Select	Answer
A	The inverse of Q factor
B	The turns ratio of a transformer
C	The inverse of impedance
D	The term for the gain of a field effect transistor

23. - E5C04

What coordinate system is often used to display the resistive, inductive, and/or capacitive reactance components of impedance?

Select	Answer
A	Rectangular coordinates
B	Maidenhead grid
C	Elliptical coordinates
D	Faraday grid

24. - E5D03

What is microstrip?

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

25. - E6A11

In Figure E6-1, what is the schematic symbol for a P-channel junction FET?

Select	Answer
A	3
B	6
C	1
D	2

26. - E6B04

What type of semiconductor device is designed for use as a voltage-controlled capacitor?

Select	Answer
A	Tunnel diode
B	Varactor diode
C	Zener diode
D	Silicon-controlled rectifier

27. - E6C10

In Figure E6-3, what is the schematic symbol for a NOR gate?

Select	Answer
A	3
B	2
C	4
D	1

28. - E6D05

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

Select	Answer
A	Ferrite toroids are easier to use with surface mount technology
B	Ferrite toroids generally require fewer turns to produce a given inductance value
C	Ferrite toroids generally have lower initial permeability
D	Ferrite toroids generally have better temperature stability

29. - E6E02

Which of the following device packages is a through-hole type?

Select	Answer
A	SOT
B	Ball grid array
C	PLCC
D	DIP

30. - E6F04

What is the photovoltaic effect?

Select	Answer
A	The conversion of electrical energy to mechanical energy
B	The conversion of voltage to current when exposed to light
C	The tendency of a battery to discharge when exposed to light
D	The conversion of light to electrical energy

31. - E7A09

What logical operation is performed by an exclusive NOR gate?

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

32. - E7B11

In Figure E7-1, what is the purpose of R3?

Select	Answer
A	Output load resistor
B	Self bias
C	Emitter bypass
D	Fixed bias

33. - E7C12

What is one advantage of a Pi-matching network over an L-matching network consisting of a single inductor and a single capacitor?

Select	Answer
A	Pi-networks provide balanced input and output
B	L-networks cannot perform impedance transformation
C	Pi-networks are more stable
D	The Q of Pi-networks can be controlled

34. - E7D04

Which of the following types of linear voltage regulator usually make the most efficient use of the primary power source?

Select	Answer
A	A shunt regulator
B	A shunt current source
C	A series regulator
D	A series current source

35. - E7E03

What is a frequency discriminator stage in a FM receiver?

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

36. - E7F13

What is the function of taps in a digital signal processing filter?

Select	Answer
A	Select the point at which baseband signals are generated
B	Provide access for debugging software
C	To reduce excess signal pressure levels
D	Provide incremental signal delays for filter algorithms

37. - E7G02

What is ringing in a filter?

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

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 quartz crystal
D	Through a tapped coil

39. - E8A02

Which of the following is a type of analog-to-digital conversion?

Select	Answer
A	Phase reversal
B	Successive approximation
C	Level shifting
D	Harmonic regeneration

40. - E8B10

What is frequency division multiplexing?

Select	Answer
A	The transmitted signal is divided into packets of information
B	The transmitted signal jumps from band to band at a predetermined rate
C	Two or more information streams are merged into a digital combiner, which then pulse position modulates the transmitter
D	Two or more information streams are merged into a baseband, which then modulates the transmitter

41. - E8C09

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

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

42. - E8D03

How does the spread spectrum technique of frequency hopping work?

Select	Answer
A	The frequency of the transmitted signal is changed very rapidly according to a pseudorandom sequence also used by the receiving station
B	If interference is detected by the receiver it will signal the transmitter to wait until the frequency is clear
C	A binary bit stream is used to shift the phase of an RF carrier very rapidly in a pseudorandom sequence
D	If interference is detected by the receiver it will signal the transmitter to change frequencies

43. - E9A04

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

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

44. - E9B08

What is the far field of an antenna?

Select	Answer
A	The region where radiated field strengths are constant
B	The region where radiated power dissipates over a specified time period
C	The region where the shape of the antenna pattern is independent of distance
D	The region of the ionosphere where radiated power is not refracted

45. - E9C07

What is the approximate feed point impedance at the center of a two-wire folded dipole antenna?

Select	Answer
A	300 ohms
B	50 ohms
C	450 ohms
D	72 ohms

46. - E9D06

What happens to the SWR bandwidth when one or more loading coils are used to resonate an electrically short antenna?

Select	Answer
A	It is decreased
B	It is unchanged if the loading coil is located at a voltage maximum point
C	It is increased
D	It is unchanged if the loading coil is located at the feed point

47. - E9E09

Which of the following is used to shunt-feed a grounded tower at its base?

Select	Answer
A	Hairpin match
B	Double-bazooka match
C	All these choices are correct
D	Gamma match

48. - E9F07

How does ladder line compare to small-diameter coaxial cable such as RG-58 at 50 MHz?

Select	Answer
A	Lower loss
B	Smaller reflection coefficient
C	Lower velocity factor
D	Higher SWR

49. - E9G11

How are the wavelength scales on a Smith chart calibrated?

Select	Answer
A	In fractions of transmission line electrical wavelength
B	In fractions of transmission line electrical frequency
C	In fractions of antenna electrical wavelength
D	In fractions of antenna electrical frequency

50. - E9H03

What is Receiving Directivity Factor (RDF)?

Select	Answer
A	Relative directivity compared to isotropic
B	Forward gain compared to the gain in the reverse direction
C	Relative directivity compared to a dipole
D	Forward gain compared to average gain over the entire hemisphere

Figure E6-1

Figure E6-3

Figure E7-1