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. - E0A01

What is the primary function of an external earth connection or ground rod?

Select	Answer
A	Lightning protection
B	Reduce received noise
C	Reduce RFI to telephones and home entertainment systems
D	Reduce RF current flow between pieces of equipment

2. - E1A07

What is the maximum power permitted on the 2200 meter band?

Select	Answer
A	5 watts EIRP (Equivalent isotropic radiated power)
B	100 watts PEP
C	50 watts PEP
D	1 watt EIRP (Equivalent isotropic radiated power)

3. - E1B05

What is the National Radio Quiet Zone?

Select	Answer
A	An area in Florida surrounding Cape Canaveral
B	An area surrounding the National Radio Astronomy Observatory
C	An area in Puerto Rico surrounding the Arecibo Radio Telescope
D	An area in New Mexico surrounding the White Sands Test Area

4. - E1C13

What notifications must be given before transmitting on the 630 meter or 2200 meter bands?

Select	Answer
A	Operators must inform the FAA of their intent to operate, giving their call sign and distance to the nearest runway
B	A special endorsement must be requested from the FCC
C	Operators must inform the Utilities Technology Council (UTC) of their call sign and coordinates of the station
D	An environmental impact statement must be filed with the Department of the Interior

5. - E1D09

Which UHF amateur bands have frequencies authorized for space stations?

Select	Answer
A	33 cm and 13 cm
B	70 cm and 13 cm
C	70 cm and 33 cm
D	70 cm only

6. - E1E12

What must the VE team do with the application form if the examinee does not pass the exam?

Select	Answer
A	Return the application document to the examinee
B	Destroy the application form
C	Maintain the application form with the VEC's records
D	Send the application form to the FCC and inform the FCC of the grade

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 purchased in used condition from an amateur operator and is sold to another amateur operator for use at that operator's station
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	FM and Digital Store-and-Forward systems
C	The 23 centimeter and 13 centimeter bands
D	The 2 meter and 70 centimeter bands

9. - E2B07

What is the name of the signal component that carries color information in NTSC video?

Select	Answer
A	Spectral intensity
B	Hue
C	Chroma
D	Luminance

10. - E2C08

Which of the following contacts may be confirmed through the U.S. QSL bureau system?

Select	Answer
A	Contacts using tactical call signs
B	Repeater contacts between U.S. club members
C	Contacts between a U.S. station and a non-U.S. station
D	Special event contacts between stations in the U.S.

11. - E2D09

What type of modulation is used for JT65 contacts?

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

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	Stations take turns on alternate days
D	Alternating transmissions at 7.5 second intervals

13. - E3A13

Which of these emission modes is best for auroral propagation?

Select	Answer
A	CW
B	FM
C	RTTY
D	SSB

14. - E3B06

Which of the following amateur bands most frequently provides long-path propagation?

Select	Answer
A	80 meters
B	10 meters
C	20 meters
D	6 meters

15. - E3C09

How does the intensity of an X3 flare compare to that of an X2 flare?

Select	Answer
A	Twice as great
B	10 percent greater
C	50 percent greater
D	Four times as great

16. - E4A05

What is the purpose of the prescaler function on a frequency counter?

Select	Answer
A	It amplifies low-level signals for more accurate counting
B	It multiplies a higher frequency signal so a low-frequency counter can display the operating frequency
C	It divides a higher frequency signal so a low-frequency counter can display the input frequency
D	It prevents oscillation in a low-frequency counter circuit

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	25 watts
B	100 watts
C	75 watts
D	125 watts

18. - E4C05

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

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

19. - E4D06

What is the term for spurious signals generated by the combination of two or more signals in a non-linear device or circuit?

Select	Answer
A	Amplifier desensitization
B	Neutralization
C	Intermodulation
D	Adjacent channel interference

20. - E4E06

What is one type of electrical interference that might be caused by a nearby personal computer?

Select	Answer
A	A whining type noise that continually pulses off and on
B	The appearance of unstable modulated or unmodulated signals at specific frequencies
C	A loud AC hum in the audio output of your station receiver
D	A clicking noise at intervals of a few seconds

21. - E5A11

What is the half-power bandwidth of a resonant circuit that has a resonant frequency of 7.1 MHz and a Q of 150?

Select	Answer
A	23.67 kHz
B	47.3 kHz
C	157.8 Hz
D	315.6 Hz

22. - E5B04

What is the time constant of a circuit having two 220-microfarad capacitors and two 1-megohm resistors, all in parallel?

Select	Answer
A	440 seconds
B	220 seconds
C	55 seconds
D	110 seconds

23. - E5C09

When using rectangular coordinates to graph the impedance of a circuit, what do the axes represent?

Select	Answer
A	The X axis represents the resistive component and the Y axis represents the reactive component
B	The X axis represents the reactive component and the Y axis represents the resistive component
C	The X axis represents the phase angle and the Y axis represents the magnitude
D	The X axis represents the magnitude and the Y axis represents the phase angle

24. - E5D13

How many watts are consumed in a circuit consisting of a 100-ohm resistor in series with a 100-ohm inductive reactance drawing 1 ampere?

Select	Answer
A	70.7 watts
B	200 watts
C	100 watts
D	141.4 watts

25. - E6A03

Why does a PN-junction diode not conduct current when reverse biased?

Select	Answer
A	Excess holes in P-type material combine with the electrons in N-type material, converting the entire diode into an insulator
B	Holes in P-type material and electrons in the N-type material are separated by the applied voltage, widening the depletion region
C	Only N-type semiconductor material can conduct current
D	Only P-type semiconductor material can conduct current

26. - E6B07

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

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

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 cause the output to change states continually
C	To allow the comparator to be used with AC input signals
D	To increase the sensitivity

28. - E6D05

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

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

29. - E6E03

Which of the following materials is likely to provide the highest frequency of operation when used in MMICs?

Select	Answer
A	Silicon dioxide
B	Silicon nitride
C	Gallium nitride
D	Silicon

30. - E6F06

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

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

31. - E7A07

What logical operation does a NAND gate perform?

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

32. - E7B17

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

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

33. - E7C01

How are the capacitors and inductors of a low-pass filter Pi-network arranged between the network's input and output?

Select	Answer
A	A capacitor is connected between the input and ground, another capacitor is connected between the output and ground, and an inductor is connected between input and output
B	Two capacitors are in series between the input and output, and an inductor is connected between the two capacitors and ground
C	An inductor is connected between the input and ground, another inductor is connected between the output and ground, and a capacitor is connected between the input and output
D	Two inductors are in series between the input and output, and a capacitor is connected between the two inductors and ground

34. - E7D02

What is a characteristic of a switching electronic voltage regulator?

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

35. - E7E06

Why is de-emphasis commonly used in FM communications receivers?

Select	Answer
A	To remove third-order distortion products
B	For compatibility with transmitters using phase modulation
C	For higher efficiency
D	To reduce impulse noise reception

36. - E7F06

What is the minimum number of bits required for an analog-to-digital converter to sample a signal with a range of 1 volt at a resolution of 1 millivolt?

Select	Answer
A	4 bits
B	8 bits
C	10 bits
D	6 bits

37. - E7G07

What magnitude of voltage gain can be expected from the circuit in Figure E73 when R1 is 10 ohms and RF is 470 ohms?

Select	Answer
A	94
B	0.21
C	47
D	24

38. - E7H08

Which of the following components can be used to reduce thermal drift in crystal oscillators?

Select	Answer
A	Toroidal inductors
B	Non-inductive resistors
C	Wirewound resistors
D	NP0 capacitors

39. - E8A01

What is the name of the process that shows that a square wave is made up of a sine wave plus all its odd harmonics?

Select	Answer
A	Fourier analysis
B	Differential analysis
C	Numerical analysis
D	Vector analysis

40. - E8B10

What is frequency division multiplexing?

Select	Answer
A	Two or more information streams are merged into a baseband, which then modulates the transmitter
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	The transmitted signal is divided into packets of information

41. - E8C04

What technique minimizes the bandwidth of a PSK31 signal?

Select	Answer
A	Use of sinusoidal data pulses
B	Use of trapezoidal data pulses
C	Reed-Solomon character encoding
D	Zero-sum character encoding

42. - E8D07

What is a common cause of overmodulation of AFSK signals?

Select	Answer
A	Excessive transmit audio levels
B	Bit errors in the modem
C	Ground loops
D	Excessive numbers of retries

43. - E9A02

What is the effective radiated power relative to a dipole of a repeater station with 150 watts transmitter power output, 2 dB feed line loss, 2.2 dB duplexer loss, and 7 dBd antenna gain?

Select	Answer
A	286 watts
B	78.7 watts
C	420 watts
D	1977 watts

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

45. - E9C01

What is the radiation pattern of two 1/4-wavelength vertical antennas spaced 1/2-wavelength apart and fed 180 degrees out of phase?

Select	Answer
A	A figure-8 oriented along the axis of the array
B	A figure-8 broadside to the axis of the array
C	Omni-directional
D	Cardioid

46. - E9D10

What happens to feed-point impedance at the base of a fixed length HF mobile antenna when operated below its resonant frequency?

Select	Answer
A	The radiation resistance increases and the capacitive reactance decreases
B	The radiation resistance decreases and the capacitive reactance decreases
C	The radiation resistance decreases and the capacitive reactance increases
D	The radiation resistance increases and the capacitive reactance increases

47. - E9E10

Which of these choices is an effective way to match an antenna with a 100-ohm feed point impedance to a 50-ohm coaxial cable feed line?

Select	Answer
A	Connect a 1/2 wavelength shorted stub of 75-ohm cable in parallel with the 50-ohm cable where it attaches to the antenna
B	Insert a 1/4-wavelength piece of 75-ohm coaxial cable transmission line in series between the antenna terminals and the 50-ohm feed cable
C	Connect a 1/4-wavelength open stub of 300-ohm twinlead in parallel with the coaxial feed line where it connects to the antenna
D	Insert a 1/2 wavelength piece of 300-ohm twinlead in series between the antenna terminals and the 50-ohm feed cable

48. - E9F03

Why is the physical length of a coaxial cable transmission line shorter than its electrical length?

Select	Answer
A	The surge impedance is higher in a parallel feed line
B	Electrical signals move more slowly in a coaxial cable than in air
C	Skin effect is less pronounced in the coaxial cable
D	The characteristic impedance is higher in a parallel feed line

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	Beam headings and radiation patterns
D	Impedance and SWR values in transmission lines

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 increases the sensitivity of a DF antenna array
D	It allows DF antennas to receive signals at different vertical angles