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. - E0A02

When evaluating RF exposure levels from your station at a neighbor's home, what must you do?

Select	Answer
A	Ensure signals from your station are less than the controlled Maximum Permitted Emission (MPE) limits
B	Ensure signals from your station are less than the controlled Maximum Permitted Exposure (MPE) limits
C	Ensure signals from your station are less than the uncontrolled Maximum Permitted Emission (MPE) limits
D	Ensure signals from your station are less than the uncontrolled Maximum Permitted Exposure (MPE) limits

2. - E1A08

If a station in a message forwarding system inadvertently forwards a message that is in violation of FCC rules, who is primarily accountable for the rules violation?

Select	Answer
A	The control operator of the originating station
B	The control operators of all the stations in the system
C	The control operator of the packet bulletin board station
D	The control operators of all the stations in the system not authenticating the source from which they accept communications

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. - E1C12

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

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

5. - E1D10

Which amateur stations are eligible to be telecommand stations of space stations (subject to the privileges of the class of operator license held by the control operator of the station)?

Select	Answer
A	All these choices are correct
B	Any amateur station so designated by the ITU
C	Any amateur station designated by NASA
D	Any amateur station so designated by the space station licensee

6. - E1E04

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

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

7. - E1F07

When may an amateur station send a message to a business?

Select	Answer
A	When the total money involved does not exceed $25
B	When transmitting international third-party communications
C	When the control operator is employed by the FCC or another government agency
D	When neither the amateur nor his or her employer has a pecuniary interest in the communications

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	Whether the satellite is in a low earth or geostationary orbit
C	Whether the satellite is in a polar or equatorial orbit
D	The satellite's uplink and downlink frequency bands

9. - E2B12

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

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

10. - E2C07

What is the Cabrillo format?

Select	Answer
A	The most common set of contest rules
B	A standard for submission of electronic contest logs
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	WSPR
B	APRS
C	Hellschreiber
D	MSK144

12. - E2E03

How is the timing of FT4 contacts organized?

Select	Answer
A	It depends on the lunar phase
B	Alternating transmissions at 7.5 second intervals
C	By exchanging ACK/NAK packets
D	Stations take turns on alternate days

13. - E3A01

What is the approximate maximum separation measured along the surface of the Earth between two stations communicating by EME?

Select	Answer
A	12,000 miles, if the moon is visible by both stations
B	5000 miles, if the moon is at perigee
C	500 miles, if the moon is at perigee
D	2000 miles, if the moon is at apogee

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	The signal experiences less loss compared to multi-hop using Earth as a reflector
D	Atmospheric noise is lower in the direction of chordal hop propagation

15. - E3C01

What does the radio communication term "ray tracing" describe?

Select	Answer
A	Determining the radiation pattern from an array of antennas
B	Modeling a radio wave's path through the ionosphere
C	The process in which an electronic display presents a pattern
D	Evaluating high voltage sources for x-rays

16. - E4A10

Which of the following displays multiple digital signal states simultaneously?

Select	Answer
A	Network analyzer
B	Bit error rate tester
C	Modulation monitor
D	Logic analyzer

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. - E4C05

What does a receiver noise floor of -174 dBm represent?

Select	Answer
A	The galactic noise contribution to minimum detectable signal
B	The noise figure of a 1 Hz bandwidth receiver
C	The theoretical noise in a 1 Hz bandwidth at the input of a perfect receiver at room temperature
D	The minimum detectable signal as a function of receive frequency

19. - E4D09

What is the purpose of the preselector in a communications receiver?

Select	Answer
A	To allow selection of the optimum RF amplifier device
B	To store often-used frequencies
C	To increase rejection of signals outside the desired band
D	To provide a range of AGC time constants

20. - E4E07

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

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

21. - E5A15

Which of the following increases Q for inductors and capacitors?

Select	Answer
A	Lower losses
B	Lower self-resonant frequency
C	Lower reactance
D	Higher self-resonant frequency

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 is unchanged
C	The sign is reversed
D	It becomes the reciprocal

23. - E5C03

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

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

24. - E5D06

In what direction is the magnetic field oriented about a conductor in relation to the direction of electron flow?

Select	Answer
A	In a circle around the conductor
B	In a direction opposite to the current
C	In the same direction as the current
D	In all directions; omni-directional

25. - E6A07

Which of the following indicates that a silicon NPN junction transistor is biased on?

Select	Answer
A	Base-to-emitter voltage of approximately 0.6 to 0.7 volts
B	Base-to-emitter resistance of approximately 0.6 to 0.7 ohms
C	Base-to-emitter resistance of approximately 6 to 7 ohms
D	Base-to-emitter voltage of approximately 6 to 7 volts

26. - E6B07

What is the failure mechanism when a junction diode fails due to excessive current?

Select	Answer
A	Insufficient forward voltage
B	Excessive inverse voltage
C	Excessive junction temperature
D	Charge carrier depletion

27. - E6C01

What is the function of hysteresis in a comparator?

Select	Answer
A	To cause the output to change states continually
B	To increase the sensitivity
C	To prevent input noise from causing unstable output signals
D	To allow the comparator to be used with AC input signals

28. - E6D07

What is current in the primary winding of a transformer called if no load is attached to the secondary?

Select	Answer
A	Magnetizing current
B	Stabilizing current
C	Excitation current
D	Direct current

29. - E6E04

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

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

30. - E6F07

What is a solid-state relay?

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

31. - E7A01

Which circuit is bistable?

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

32. - E7B08

How can an RF power amplifier be neutralized?

Select	Answer
A	By feeding a 180-degree out-of-phase portion of the output back to the input
B	By reducing the driving power
C	By increasing the driving power
D	By feeding an in-phase component of the output back to the input

33. - E7C03

What advantage does a series-L Pi-L-network have over a series-L Pi-network for impedance matching between the final amplifier of a vacuum-tube transmitter and an antenna?

Select	Answer
A	Greater harmonic suppression
B	Higher efficiency
C	Greater transformation range
D	Does not require a capacitor

34. - E7D07

What is the purpose of C2 in the circuit shown in Figure E7-2?

Select	Answer
A	It is a brute force filter for the output
B	To self-resonate at the hum frequency
C	It bypasses rectifier output ripple around D1
D	To provide fixed DC bias for Q1

35. - E7E05

What circuit is added to an FM transmitter to boost the higher audio frequencies?

Select	Answer
A	A pre-emphasis network
B	A heterodyne suppressor
C	A heterodyne enhancer
D	A de-emphasis network

36. - E7F11

What sets the minimum detectable signal level for a direct-sampling SDR receiver in the absence of atmospheric or thermal noise?

Select	Answer
A	Missing codes and jitter
B	Reference voltage level and sample width in bits
C	Sample clock phase noise
D	Data storage transfer rate

37. - E7G06

What is the gain-bandwidth of an operational amplifier?

Select	Answer
A	The frequency at which the amplifier's offset voltage is zero
B	The frequency at which the open-loop gain of the amplifier equals one
C	The gain of the amplifier at a filter's cutoff frequency
D	The maximum frequency for a filter circuit using that type of amplifier

38. - E7H05

How is positive feedback supplied in a Pierce oscillator?

Select	Answer
A	Through a tapped coil
B	Through a quartz crystal
C	Through link coupling
D	Through a neutralizing capacitor

39. - E8A02

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

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

40. - E8B05

What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus-or-minus 5 kHz when the maximum modulation frequency is 3 kHz?

Select	Answer
A	60
B	0.6
C	1.67
D	0.167

41. - E8C11

What is the relationship between symbol rate and baud?

Select	Answer
A	Symbol rate is only used for packet-based modes
B	Baud is twice the symbol rate
C	Baud is only used for RTTY
D	They are the same

42. - E8D10

What are some of the differences between the Baudot digital code and ASCII?

Select	Answer
A	Baudot uses 7 data bits per character, ASCII uses 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes
B	Baudot uses 5 data bits per character, ASCII uses 7 or 8; Baudot uses 2 characters as letters/figures shift codes, ASCII has no letters/figures shift code
C	Baudot uses 4 data bits per character, ASCII uses 7 or 8; Baudot uses 1 character as a letters/figures shift code, ASCII has no letters/figures code
D	Baudot uses 6 data bits per character, ASCII uses 7 or 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes

43. - E9A13

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

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

44. - E9B03

In the antenna radiation pattern shown in Figure E9-1, what is the front-to-side ratio?

Select	Answer
A	12 dB
B	18 dB
C	14 dB
D	24 dB

45. - E9C06

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

Select	Answer
A	It reflects the standing waves on the antenna elements back to the transmitter
B	It changes the radiation pattern from bidirectional to unidirectional
C	It decreases the ground loss
D	It changes the radiation pattern from horizontal to vertical polarization

46. - E9D03

Where should a high Q loading coil be placed to minimize losses in a shortened vertical antenna?

Select	Answer
A	At a voltage node
B	As close to the transmitter as possible
C	Near the center of the vertical radiator
D	As low as possible on the vertical radiator

47. - E9E02

What is the name of an antenna matching system that matches an unbalanced feed line to an antenna by feeding the driven element both at the center of the element and at a fraction of a wavelength to one side of center?

Select	Answer
A	The delta match
B	The gamma match
C	The epsilon match
D	The stub match

48. - E9F06

What is the approximate physical length of an air-insulated, parallel conductor transmission line that is electrically 1/2 wavelength long at 14.10 MHz?

Select	Answer
A	10.6 meters
B	13.3 meters
C	8.5 meters
D	7.0 meters

49. - E9G09

What third family of circles is often added to a Smith chart during the process of solving problems?

Select	Answer
A	Standing wave ratio circles
B	Coaxial-length circles
C	Antenna-length circles
D	Radiation-pattern circles

50. - E9H04

What is an advantage of placing a grounded electrostatic shield around a small loop direction-finding antenna?

Select	Answer
A	It adds capacitive loading, increasing the bandwidth of the antenna
B	It eliminates unbalanced capacitive coupling to the surroundings, improving the nulls
C	It increases signal strength by providing a better match to the feed line
D	It eliminates tracking errors caused by strong out-of-band signals

Figure E7-2

Figure E9-1