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. - E0A10

What toxic material may be present in some electronic components such as high voltage capacitors and transformers?

Select	Answer
A	Polymorphic silicon
B	Polyethylene
C	Polytetrafluoroethylene
D	Polychlorinated biphenyls

2. - E1A04

With your transceiver displaying the carrier frequency of phone signals, you hear a DX station calling CQ on 3.601 MHz LSB. Is it legal to return the call using lower sideband on the same frequency?

Select	Answer
A	Yes, because the DX station initiated the contact
B	No, the sideband will extend beyond the edge of the phone band segment
C	Yes, because the displayed frequency is within the 75 meter phone band segment
D	No, U.S. stations are not permitted to use phone emissions below 3.610 MHz

3. - E1B08

What limitations may the FCC place on an amateur station if its signal causes interference to domestic broadcast reception, assuming that the receivers involved are of good engineering design?

Select	Answer
A	The amateur station must cease operation
B	The amateur station must cease operation on all frequencies below 30 MHz
C	The amateur station must cease operation on all frequencies above 30 MHz
D	The amateur station must avoid transmitting during certain hours on frequencies that cause the interference

4. - E1C02

Which of the following types of communications may be transmitted to amateur stations in foreign countries?

Select	Answer
A	All these choices are correct
B	Messages intended for users of the maritime satellite service
C	Business-related messages for non-profit organizations
D	Communications incidental to the purpose of the amateur service and remarks of a personal nature

5. - E1D12

Which of the following amateur stations may transmit one-way communications?

Select	Answer
A	All these choices are correct
B	A space station, beacon station, or telecommand station
C	A local repeater or linked repeater station
D	A message forwarding station or automatically controlled digital station

6. - E1E05

What is the minimum passing score on all amateur operator license examinations?

Select	Answer
A	Minimum passing score of 70%
B	Minimum passing score of 80%
C	Minimum passing score of 77%
D	Minimum passing score of 74%

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 a country that does not require certification of RF power amplifiers
D	It was imported from a manufacturer in another country and was certificated by that country's government

8. - E2A09

What do the terms L band and S band specify regarding satellite communications?

Select	Answer
A	Which sideband to use
B	The 23 centimeter and 13 centimeter bands
C	The 2 meter and 70 centimeter bands
D	FM and Digital Store-and-Forward systems

9. - E2B12

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

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

10. - E2C06

During a VHF/UHF contest, in which band segment would you expect to find the highest level of SSB or CW activity?

Select	Answer
A	At the top of each band, usually in a segment reserved for contests
B	In the middle of the band, usually 25 kHz above the national calling frequency
C	In the weak signal segment of the band, with most of the activity near the calling frequency
D	In the middle of each band, usually on the national calling frequency

11. - E2D09

What type of modulation is used for JT65 contacts?

Select	Answer
A	RTTY
B	Multi-tone AFSK
C	PSK
D	IEEE 802.11

12. - E2E03

How is the timing of FT4 contacts organized?

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

13. - E3A14

What is meant by circularly polarized electromagnetic waves?

Select	Answer
A	Waves with a rotating electric field
B	Waves that circle the Earth
C	Waves produced by a loop antenna
D	Waves with an electric field bent into a circular shape

14. - E3B03

What is the best time of day for transequatorial propagation?

Select	Answer
A	Noon
B	Late at night
C	Morning
D	Afternoon or early evening

15. - E3C05

What orientation of Bz (B sub z) increases the likelihood that incoming particles from the sun will cause disturbed conditions?

Select	Answer
A	Northward
B	Eastward
C	Southward
D	Westward

16. - E4A09

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

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

17. - E4B10

Which of the following methods measures intermodulation distortion in an SSB transmitter?

Select	Answer
A	Modulate the transmitter using two AF signals having harmonically related frequencies and observe the RF output with a peak reading wattmeter
B	Modulate the transmitter using two RF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer
C	Modulate the transmitter using two RF signals having harmonically related frequencies and observe the RF output with a logic analyzer
D	Modulate the transmitter using two AF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer

18. - E4C04

What is the noise figure of a receiver?

Select	Answer
A	The ratio of thermal noise to atmospheric noise
B	The ratio in dB of the noise generated by the receiver to the theoretical minimum noise
C	The ratio of atmospheric noise to phase noise
D	The ratio of the noise bandwidth in hertz to the theoretical bandwidth of a resistive network

19. - E4D07

Which of the following reduces the likelihood of receiver desensitization?

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

20. - E4E09

What undesirable effect can occur when using an IF noise blanker?

Select	Answer
A	Received audio in the speech range might have an echo effect
B	The audio frequency bandwidth of the received signal might be compressed
C	FM signals can no longer be demodulated
D	Nearby signals may appear to be excessively wide even if they meet emission standards

21. - E5A02

What is resonance in an LC or RLC circuit?

Select	Answer
A	The frequency at which the capacitive reactance equals the inductive reactance
B	The frequency at which the reactive impedance equals the resistive impedance
C	The lowest frequency that will pass current
D	The highest frequency that will pass current

22. - E5B11

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 25 ohms, R is 100 ohms, and XL is 50 ohms?

Select	Answer
A	76 degrees with the voltage lagging the current
B	14 degrees with the voltage leading the current
C	14 degrees with the voltage lagging the current
D	76 degrees with the voltage leading the current

23. - E5C04

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

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

24. - E5D01

What is the result of skin effect?

Select	Answer
A	As frequency decreases, RF current flows in a thinner layer of the conductor, closer to the surface
B	Thermal effects on the surface of the conductor decrease the impedance
C	As frequency increases, RF current flows in a thinner layer of the conductor, closer to the surface
D	Thermal effects on the surface of the conductor increase the impedance

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

26. - E6B05

What characteristic of a PIN diode makes it useful as an RF switch?

Select	Answer
A	Ability to dissipate large amounts of power
B	Low junction capacitance
C	Reverse bias controls its forward voltage drop
D	Extremely high reverse breakdown voltage

27. - E6C10

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

Select	Answer
A	2
B	4
C	1
D	3

28. - E6D09

What devices are commonly used as VHF and UHF parasitic suppressors at the input and output terminals of a transistor HF amplifier?

Select	Answer
A	Steel-core toroids
B	Electrolytic capacitors
C	Butterworth filters
D	Ferrite beads

29. - E6E01

Why is gallium arsenide (GaAs) useful for semiconductor devices operating at UHF and higher frequencies?

Select	Answer
A	Higher noise figures
B	Lower transconductance
C	Lower junction voltage drop
D	Higher electron mobility

30. - E6F09

What is the efficiency of a photovoltaic cell?

Select	Answer
A	The relative fraction of light that is converted to current
B	Cost per kilowatt-hour generated
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. - E7A07

What logical operation does a NAND gate perform?

Select	Answer
A	It produces logic 0 at its output if some but not all inputs are logic 1
B	It produces logic 0 at its output only when all inputs are logic 1
C	It produces logic 0 at its output only when all inputs are logic 0
D	It produces logic 1 at its output only when all inputs are logic 1

32. - E7B06

Which of the following amplifier types reduces even-order harmonics?

Select	Answer
A	Push-pull
B	Push-push
C	Class C
D	Class AB

33. - E7C09

What is a crystal lattice filter?

Select	Answer
A	A power supply filter made with interlaced quartz crystals
B	An audio filter made with four quartz crystals that resonate at 1 kHz intervals
C	A filter using lattice-shaped quartz crystals for high-Q performance
D	A filter with narrow bandwidth and steep skirts made using quartz crystals

34. - E7D10

What is the primary reason that a high-frequency switching type high-voltage power supply can be both less expensive and lighter in weight than a conventional power supply?

Select	Answer
A	It uses a diode bridge rectifier for increased output
B	The inverter design does not require any output filtering
C	It uses a large power factor compensation capacitor to recover power from the unused portion of the AC cycle
D	The high frequency inverter design uses much smaller transformers and filter components for an equivalent power output

35. - E7E10

How does a diode envelope detector function?

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

36. - E7F12

Which of the following is an advantage of a Finite Impulse Response (FIR) filter vs an Infinite Impulse Response (IIR) digital filter?

Select	Answer
A	FIR filters can respond faster to impulses
B	FIR filters can delay all frequency components of the signal by the same amount
C	All these choices are correct
D	FIR filters are easier to implement for a given set of passband rolloff requirements

37. - E7G09

What will be the output voltage of the circuit shown in Figure E7-3 if R1 is 1000 ohms, RF is 10,000 ohms, and 0.23 volts DC is applied to the input?

Select	Answer
A	0.23 volts
B	2.3 volts
C	-0.23 volts
D	-2.3 volts

38. - E7H05

How is positive feedback supplied in a Pierce oscillator?

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

39. - E8A03

What type of wave does a Fourier analysis show to be made up of sine waves of a given fundamental frequency plus all its harmonics?

Select	Answer
A	A sawtooth wave
B	A cosine wave
C	A sine wave
D	A square wave

40. - E8B04

What is the modulation index of an FM-phone signal having a maximum carrier deviation of plus or minus 6 kHz when modulated with a 2 kHz modulating frequency?

Select	Answer
A	6000
B	3
C	1/3
D	2000

41. - E8C01

How is Forward Error Correction implemented?

Select	Answer
A	By transmitting a special algorithm to the receiving station along with the data characters
B	By the receiving station repeating each block of three data characters
C	By varying the frequency shift of the transmitted signal according to a predefined algorithm
D	By transmitting extra data that may be used to detect and correct transmission errors

42. - E8D11

What is one advantage of using ASCII code for data communications?

Select	Answer
A	It is possible to transmit both upper and lower case text
B	It includes built-in error correction features
C	It uses one character as a shift code to send numeric and special characters
D	It contains fewer information bits per character than any other code

43. - E9A08

What is antenna bandwidth?

Select	Answer
A	The frequency range over which an antenna satisfies a performance requirement
B	The angle between the half-power radiation points
C	The angle formed between two imaginary lines drawn through the element ends
D	Antenna length divided by the number of elements

44. - E9B09

What type of computer program technique is commonly used for modeling antennas?

Select	Answer
A	Mutual impedance analysis
B	Graphical analysis
C	Method of Moments
D	Calculus differentiation with respect to physical properties

45. - E9C03

What is the radiation pattern of two 1/4-wavelength vertical antennas spaced 1/2-wavelength apart and fed in phase?

Select	Answer
A	A Figure-8 broadside to the axis of the array
B	Omni-directional
C	Cardioid
D	A Figure-8 end-fire along the axis of the array

46. - E9D04

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

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

47. - E9E01

What system matches a higher-impedance transmission line to a lower-impedance antenna by connecting the line to the driven element in two places spaced a fraction of a wavelength each side of element center?

Select	Answer
A	The stub matching system
B	The delta matching system
C	The omega matching system
D	The gamma matching system

48. - E9F10

What impedance does a 1/8-wavelength transmission line present to a generator when the line is shorted at the far end?

Select	Answer
A	A capacitive reactance
B	Zero
C	The same as the characteristic impedance of the line
D	An inductive reactance

49. - E9G03

Which of the following is often determined using a Smith chart?

Select	Answer
A	Trigonometric functions
B	Satellite azimuth and elevation bearings
C	Impedance and SWR values in transmission lines
D	Beam headings and radiation patterns

50. - E9H08

What is the function of a sense antenna?

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

Figure E6-3

Figure E7-3