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

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1. - E0A03

Over what range of frequencies are the FCC human body RF exposure limits most restrictive?

Select	Answer
A	30 to 300 MHz
B	300 kHz to 3 MHz
C	300 to 3000 MHz
D	3 to 30 MHz

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	14.100 MHz
D	14.149 MHz

3. - E1B07

To what type of regulations does PRB-1 apply?

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

4. - E1C09

What is the highest modulation index permitted at the highest modulation frequency for angle modulation below 29.0 MHz?

Select	Answer
A	3.0
B	2.0
C	1.0
D	0.5

5. - E1D04

Which of the following is required in the identification transmissions from a balloon-borne telemetry station?

Select	Answer
A	The station's six-character Maidenhead grid locator
B	Call sign
C	All these choices are correct
D	The output power of the balloon transmitter

6. - E1E06

Who is responsible for the proper conduct and necessary supervision during an amateur operator license examination session?

Select	Answer
A	The VEC coordinating the session
B	The FCC
C	The VE session manager
D	Each administering VE

7. - E1F03

Under what circumstances may a dealer sell an external RF power amplifier capable of operation below 144 MHz if it has not been granted FCC certification?

Select	Answer
A	The equipment dealer assembled it from a kit
B	It was imported from a manufacturer in a country that does not require certification of RF power amplifiers
C	It was imported from a manufacturer in another country and was certificated by that country's government
D	It was purchased in used condition from an amateur operator and is sold to another amateur operator for use at that operator's station

8. - E2A05

What do the letters in a satellite's mode designator specify?

Select	Answer
A	Power limits for uplink and downlink transmissions
B	The polarization of uplink and downlink signals
C	The uplink and downlink frequency ranges
D	The location of the ground control station

9. - E2B12

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

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

10. - E2C09

What type of equipment is commonly used to implement an amateur radio mesh network?

Select	Answer
A	An optical cable connection between the USB ports of 2 separate computers
B	A 2 meter VHF transceiver with a 1200 baud modem
C	A wireless router running custom firmware
D	A 440 MHz transceiver with a 9600 baud modem

11. - E2D03

Which of the following digital modes is especially useful for EME communications?

Select	Answer
A	MSK144
B	JT65
C	Olivia
D	PACTOR III

12. - E2E02

What do the letters FEC mean as they relate to digital operation?

Select	Answer
A	Forward Error Correction
B	First Error Correction
C	Fatal Error Correction
D	Final Error Correction

13. - E3A02

What characterizes libration fading of an EME signal?

Select	Answer
A	The returning echo is several hertz lower in frequency than the transmitted signal
B	A gradual loss of signal as the sun rises
C	A slow change in the pitch of the CW signal
D	A fluttery irregular fading

14. - E3B01

What is transequatorial propagation?

Select	Answer
A	Propagation between two mid-latitude points at approximately the same distance north and south of the magnetic equator
B	Propagation between points located on the magnetic equator
C	Propagation between points at the same latitude
D	Propagation between a point on the equator and its antipodal point

15. - E3C13

What type of polarization is best for ground-wave propagation?

Select	Answer
A	Vertical
B	Circular
C	Elliptical
D	Horizontal

16. - E4A02

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

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

17. - E4B08

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

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

18. - E4C13

How does a narrow-band roofing filter affect receiver performance?

Select	Answer
A	It improves intelligibility by using low Q circuitry to reduce ringing
B	It improves dynamic range by attenuating strong signals near the receive frequency
C	It improves sensitivity by reducing front end noise
D	All these choices are correct

19. - E4D03

How can intermodulation interference between two repeaters occur?

Select	Answer
A	When the repeaters are in close proximity and the signals mix in the final amplifier of one or both transmitters
B	When the repeaters are in close proximity and the signals cause feedback in the final amplifier of one or both transmitters
C	When the signals from the transmitters are reflected in phase from airplanes passing overhead
D	When the signals from the transmitters are reflected out of phase from airplanes passing overhead

20. - E4E03

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

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

21. - E5A04

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

Select	Answer
A	Approximately equal to circuit resistance
B	Low compared to the circuit resistance
C	High compared to the circuit resistance
D	Approximately equal to inductive reactance

22. - E5B02

What letter is commonly used to represent susceptance?

Select	Answer
A	G
B	Y
C	X
D	B

23. - E5C11

Which point in Figure E5-1 best represents the impedance of a series circuit consisting of a 300-ohm resistor and an 18-microhenry inductor at 3.505 MHz?

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

24. - E5D11

What is the power factor of an RL circuit having a 60-degree phase angle between the voltage and the current?

Select	Answer
A	0.866
B	1.73
C	0.5
D	1.414

25. - E6A05

How does DC input impedance at the gate of a field-effect transistor compare with the DC input impedance of a bipolar transistor?

Select	Answer
A	They are both high impedance
B	An FET has lower input impedance
C	They are both low impedance
D	An FET has higher input impedance

26. - E6B10

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

Select	Answer
A	6
B	7
C	1
D	5

27. - E6C05

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

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

28. - E6D05

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

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

29. - E6E08

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

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

30. - E6F06

Which of these materials is most commonly used to create photoconductive devices?

Select	Answer
A	A heavy metal
B	An ordinary metal
C	A crystalline semiconductor
D	A liquid semiconductor

31. - E7A03

Which of the following can divide the frequency of a pulse train by 2?

Select	Answer
A	A flip-flop
B	An OR gate
C	An XOR gate
D	A multiplexer

32. - E7B17

Why are odd-order rather than even-order intermodulation distortion products of concern in linear power amplifiers?

Select	Answer
A	Because they maintain the sidebands, thus causing multiple duplicate signals
B	Because they invert the sidebands causing distortion
C	Because they are relatively close in frequency to the desired signal
D	Because they are relatively far in frequency from the desired signal

33. - E7C05

Which filter type is described as having ripple in the passband and a sharp cutoff?

Select	Answer
A	A Chebyshev filter
B	A passive op-amp filter
C	An active LC filter
D	A Butterworth filter

34. - E7D02

What is a characteristic of a switching electronic voltage regulator?

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

35. - E7E10

How does a diode envelope detector function?

Select	Answer
A	By rectification and filtering of RF signals
B	By sensing the change of reactance in the diode with respect to frequency
C	By mixing signals with noise in the transition region of the diode
D	By breakdown of the Zener voltage

36. - E7F01

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

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

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	38
B	1
C	76
D	0.03

38. - E7H04

How is positive feedback supplied in a Colpitts oscillator?

Select	Answer
A	Through link coupling
B	Through a tapped coil
C	Through a neutralizing capacitor
D	Through a capacitive divider

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	256 divided by the gain of the input amplifier
C	8
D	256

40. - E8B01

What is the modulation index of an FM signal?

Select	Answer
A	The ratio of modulating signal amplitude to frequency deviation
B	The type of modulation used by the transmitter
C	The bandwidth of the transmitted signal divided by the modulating signal frequency
D	The ratio of frequency deviation to modulating signal frequency

41. - E8C03

Why should phase-shifting of a PSK signal be done at the zero crossing of the RF signal?

Select	Answer
A	To simplify modulation
B	To minimize bandwidth
C	All these choices are correct
D	To improve carrier suppression

42. - E8D04

What is the primary effect of extremely short rise or fall time on a CW signal?

Select	Answer
A	The generation of key clicks
B	Limits data speed
C	The generation of RF harmonics
D	More difficult to copy

43. - E9A12

How much gain does an antenna have compared to a 1/2-wavelength dipole when it has 6 dB gain over an isotropic antenna?

Select	Answer
A	6.0 dB
B	8.15 dB
C	2.79 dB
D	3.85 dB

44. - E9B01

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

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

45. - E9C10

Which of the following describes a Zepp antenna?

Select	Answer
A	An end-fed dipole antenna
B	An omni-directional antenna commonly used for satellite communications
C	A dipole constructed from zip cord
D	A vertical array capable of quickly changing the direction of maximum radiation by changing phasing lines

46. - E9D02

How can linearly polarized Yagi antennas be used to produce circular polarization?

Select	Answer
A	Stack two Yagis fed in phase to form an array with the respective elements in parallel planes
B	Arrange two Yagis collinear to each other with the driven elements fed 180 degrees out of phase
C	Arrange two Yagis perpendicular to each other with the driven elements at the same point on the boom fed 90 degrees out of phase
D	Stack two Yagis fed 90 degrees out of phase to form an array with the respective elements in parallel planes

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. - E9F02

Which of the following has the biggest effect on the velocity factor of a transmission line?

Select	Answer
A	The line length
B	Dielectric materials used in the line
C	The center conductor resistivity
D	The termination impedance

49. - E9G11

How are the wavelength scales on a Smith chart calibrated?

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

50. - E9H05

What is the main drawback of a small wire-loop antenna for direction finding?

Select	Answer
A	All these choices are correct
B	It is practical for use only on VHF and higher bands
C	It has no clearly defined null
D	It has a bidirectional pattern

Figure E5-1

Figure E6-2

Figure E7-3

Figure E9-1