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

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1. - E0A05

What is one of the potential hazards of operating in the amateur radio microwave bands?

Select	Answer
A	The high gain antennas commonly used can result in high exposure levels
B	The extremely high frequency energy can damage the joints of antenna structures
C	Microwaves are ionizing radiation
D	Microwaves often travel long distances by ionospheric reflection

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

3. - E1B10

What frequencies are authorized to an amateur station operating under RACES rules?

Select	Answer
A	Specific segments in the amateur service MF, HF, VHF and UHF bands
B	Military Auxiliary Radio System (MARS) channels
C	Specific local government channels
D	All amateur service frequencies authorized to the control operator

4. - E1C05

When may an automatically controlled station originate third party communications?

Select	Answer
A	Only when transmitting RTTY or data emissions
B	When agreed upon by the sending or receiving station
C	Never
D	When approved by the National Telecommunication and Information Administration

5. - E1D02

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

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

6. - E1E03

What is a Volunteer Examiner Coordinator?

Select	Answer
A	An organization that has entered into an agreement with the FCC to coordinate, prepare, and administer amateur operator license examinations
B	The person who has entered into an agreement with the FCC to be the VE session manager
C	A person who has volunteered to administer amateur operator license examinations
D	A person who has volunteered to prepare amateur operator license examinations

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

8. - E2A03

How is the signal inverted by an inverting linear transponder?

Select	Answer
A	The signal is passed through a non-linear filter
B	The signal is reduced to I and Q components and the Q component is filtered out
C	The signal is passed through a mixer and the difference rather than the sum is transmitted
D	The signal is detected and remodulated on the reverse sideband

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. - E2C12

What technique do individual nodes use to form a mesh network?

Select	Answer
A	Custom code plugs for the local trunking systems
B	Acting as store-and-forward digipeaters
C	Discovery and link establishment protocols
D	Forward error correction and Viterbi codes

11. - E2D08

What type of packet frame is used to transmit APRS beacon data?

Select	Answer
A	Connect
B	Acknowledgement
C	Unnumbered Information
D	Disconnect

12. - E2E13

Which of these digital modes has the fastest data throughput under clear communication conditions?

Select	Answer
A	300 baud packet
B	170 Hz shift, 45 baud RTTY
C	AMTOR
D	PSK31

13. - E3A11

What is a typical range for tropospheric propagation of microwave signals?

Select	Answer
A	2500 miles
B	1200 miles
C	10 miles to 50 miles
D	100 miles to 300 miles

14. - E3B10

Why is chordal hop propagation desirable?

Select	Answer
A	Signals travel faster along ionospheric chords
B	The MUF for chordal hop propagation is much lower than for normal skip propagation
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. - E3C02

What is indicated by a rising A or K index?

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

16. - E4A04

How is the compensation of an oscilloscope probe typically adjusted?

Select	Answer
A	A DC voltage standard is displayed and the probe is adjusted until the displayed voltage is accurate
B	A frequency standard is displayed and the probe is adjusted until the deflection time is accurate
C	A high frequency sine wave is displayed and the probe is adjusted for maximum amplitude
D	A square wave is displayed and the probe is adjusted until the horizontal portions of the displayed wave are as nearly flat as possible

17. - E4B11

Which of the following can be measured with a vector network analyzer?

Select	Answer
A	Reflection coefficient
B	All these choices are correct
C	Input impedance
D	Output impedance

18. - E4C07

What does the MDS of a receiver represent?

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

19. - E4D04

Which of the following may reduce or eliminate intermodulation interference in a repeater caused by another transmitter operating in close proximity?

Select	Answer
A	Utilizing a Class C final amplifier
B	Utilizing a Class D final amplifier
C	A properly terminated circulator at the output of the repeater's transmitter
D	A band-pass filter in the feed line between the transmitter and receiver

20. - E4E11

What could cause local AM broadcast band signals to combine to generate spurious signals in the MF or HF bands?

Select	Answer
A	Nearby corroded metal joints are mixing and re-radiating the broadcast signals
B	One or more of the broadcast stations is transmitting an over-modulated signal
C	You are receiving skywave signals from a distant station
D	Your station receiver IF amplifier stage is defective

21. - E5A04

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

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

22. - E5B12

What is admittance?

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

23. - E5C01

Which of the following represents capacitive reactance in rectangular notation?

Select	Answer
A	-jX
B	Delta
C	+jX
D	Omega

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	1.0
B	0.707
C	0.5
D	0.866

25. - E6A10

In Figure E6-1, what is the schematic symbol for an N-channel dual-gate MOSFET?

Select	Answer
A	6
B	2
C	4
D	5

26. - E6B09

What is a common use for point-contact diodes?

Select	Answer
A	As a constant voltage source
B	As an RF detector
C	As a high-voltage rectifier
D	As a constant current source

27. - E6C01

What is the function of hysteresis in a comparator?

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

28. - E6D03

Which of the following is an aspect of the piezoelectric effect?

Select	Answer
A	Mechanical deformation of material by the application of a voltage
B	Increased conductivity in the presence of light
C	Generation of electrical energy in the presence of light
D	Mechanical deformation of material by the application of a magnetic field

29. - E6E09

Which of the following component package types would be most suitable for use at frequencies above the HF range?

Select	Answer
A	TO-220
B	Axial lead
C	Surface mount
D	Radial lead

30. - E6F09

What is the efficiency of a photovoltaic cell?

Select	Answer
A	Cost per kilowatt-hour generated
B	The relative fraction of light that is converted to current
C	The open-circuit voltage divided by the short-circuit current under full illumination
D	The output RF power divided by the input DC power

31. - E7A05

Which of the following is a circuit that continuously alternates between two states without an external clock?

Select	Answer
A	T flip-flop
B	Astable multivibrator
C	Monostable multivibrator
D	J-K flip-flop

32. - E7B07

Which of the following is a likely result when a Class C amplifier is used to amplify a single-sideband phone signal?

Select	Answer
A	Reduced intermodulation products
B	Signal inversion
C	Increased overall intelligibility
D	Signal distortion and excessive bandwidth

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

34. - E7D09

What is the main reason to use a charge controller with a solar power system?

Select	Answer
A	Prevention of battery damage due to overcharge
B	Matching of day and night charge rates
C	Control of electrolyte levels during battery discharge
D	Prevention of battery undercharge

35. - E7E01

Which of the following can be used to generate FM phone emissions?

Select	Answer
A	A balanced modulator on the oscillator
B	A balanced modulator on the audio amplifier
C	A reactance modulator on the oscillator
D	A reactance modulator on the final amplifier

36. - E7F09

Why is an anti-aliasing digital filter required in a digital decimator?

Select	Answer
A	It removes low-frequency signal components to eliminate the need for DC restoration
B	It removes high-frequency signal components that would otherwise be reproduced as lower frequency components
C	It notches out the sampling frequency to avoid sampling errors
D	It peaks the response of the decimator, improving bandwidth

37. - E7G11

What absolute voltage gain can be expected from the circuit in Figure E7-3 when R1 is 3300 ohms and RF is 47 kilohms?

Select	Answer
A	0.07
B	14
C	28
D	7

38. - E7H04

How is positive feedback supplied in a Colpitts oscillator?

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

39. - E8A11

Which of the following is a measure of the quality of an analog-to-digital converter?

Select	Answer
A	Total harmonic distortion
B	Peak envelope power
C	Reciprocal mixing
D	Power factor

40. - E8B11

What is digital time division multiplexing?

Select	Answer
A	Two or more signals are arranged to share discrete time slots of a data transmission
B	Two or more data streams are assigned to discrete sub-carriers on an FM transmitter
C	Two or more signals are quadrature modulated to increase bandwidth efficiency
D	Two or more data streams share the same channel by transmitting time of transmission as the sub-carrier

41. - E8C09

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

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

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

43. - E9A03

What is the radiation resistance of an antenna?

Select	Answer
A	The value of a resistance that would dissipate the same amount of power as that radiated from an antenna
B	The resistance in the atmosphere that an antenna must overcome to be able to radiate a signal
C	The combined losses of the antenna elements and feed line
D	The specific impedance of the antenna

44. - E9B07

How does the total amount of radiation emitted by a directional gain antenna compare with the total amount of radiation emitted from a theoretical isotropic antenna, assuming each is driven by the same amount of power?

Select	Answer
A	They are the same
B	The total amount of radiation from the directional antenna is stronger by its front-to-back ratio
C	The total amount of radiation from the directional antenna is increased by the gain of the antenna
D	The radiation from the isotropic antenna is 2.15 dB stronger than that from the directional antenna

45. - E9C13

How does the radiation pattern of a horizontally polarized 3-element beam antenna vary with increasing height above ground?

Select	Answer
A	The horizontal beamwidth increases
B	The takeoff angle of the lowest elevation lobe increases
C	The horizontal beamwidth decreases
D	The takeoff angle of the lowest elevation lobe decreases

46. - E9D04

Why should an HF mobile antenna loading coil have a high ratio of reactance to resistance?

Select	Answer
A	To swamp out harmonics
B	To minimize the Q
C	To lower the radiation angle
D	To minimize losses

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	450 ohms
C	50 ohms
D	75 ohms

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	13.3 meters
B	7.0 meters
C	10.6 meters
D	8.5 meters

49. - E9G02

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

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

50. - E9H08

What is the function of a sense antenna?

Select	Answer
A	It increases the sensitivity of a DF antenna array
B	It provides diversity reception that cancels multipath signals
C	It modifies the pattern of a DF antenna array to provide a null in one direction
D	It allows DF antennas to receive signals at different vertical angles

Figure E6-1

Figure E7-3