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. - E0A04

When evaluating a site with multiple transmitters operating at the same time, the operators and licensees of which transmitters are responsible for mitigating over-exposure situations?

Select	Answer
A	Only commercial transmitters
B	Only the most powerful transmitter
C	Each transmitter operating with a duty cycle greater than 50 percent
D	Each transmitter that produces 5 percent or more of its MPE limit in areas where the total MPE limit is exceeded.

2. - E1A01

Which of the following carrier frequencies is illegal for LSB AFSK emissions on the 17 meter band RTTY and data segment of 18.068 to 18.110 MHz?

Select	Answer
A	18.110 MHz
B	18.068 MHz
C	18.100 MHz
D	18.107 MHz

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 in Puerto Rico surrounding the Arecibo Radio Telescope
C	An area surrounding the National Radio Astronomy Observatory
D	An area in Florida surrounding Cape Canaveral

4. - E1C10

What is the permitted mean power of any spurious emission relative to the mean power of the fundamental emission from a station transmitter or external RF amplifier installed after January 1, 2003 and transmitting on a frequency below 30 MHz?

Select	Answer
A	At least 53 dB below
B	At least 63 dB below
C	At least 43 dB below
D	At least 73 dB below

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	Telecommand signals from a space telecommand station
D	Auxiliary relay links carrying repeater audio

6. - E1E08

To which of the following examinees may a VE not administer an examination?

Select	Answer
A	Friends of the VE
B	Relatives of the VE as listed in the FCC rules
C	All these choices are correct
D	Employees of the VE

7. - E1F08

Which of the following types of amateur station communications are prohibited?

Select	Answer
A	Communications that have religious content
B	Communications in a language other than English
C	Communications that have political content, except as allowed by the Fairness Doctrine
D	Communications transmitted for hire or material compensation, except as otherwise provided in the rules

8. - E2A13

Which of the following techniques is normally used by low Earth orbiting digital satellites to relay messages around the world?

Select	Answer
A	Digipeating
B	Store-and-forward
C	Node hopping
D	Multi-satellite relaying

9. - E2B02

How many horizontal lines make up a fast-scan (NTSC) television frame?

Select	Answer
A	30
B	525
C	1080
D	60

10. - E2C01

What indicator is required to be used by U.S.-licensed operators when operating a station via remote control and the remote transmitter is located in the U.S.?

Select	Answer
A	/ followed by the ARRL Section of the remote station
B	No additional indicator is required
C	/R# where # is the district of the remote station
D	/ followed by the USPS two-letter abbreviation for the state in which the remote station is located

11. - E2D08

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

Select	Answer
A	Disconnect
B	Unnumbered Information
C	Acknowledgement
D	Connect

12. - E2E03

How is the timing of FT4 contacts organized?

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

13. - E3A06

What might help to restore contact when DX signals become too weak to copy across an entire HF band a few hours after sunset?

Select	Answer
A	Switch to a lower frequency HF band
B	Wait 24 hours before attempting another communication on the band
C	Switch to a higher frequency HF band
D	Wait 90 minutes or so for the signal degradation to pass

14. - E3B03

What is the best time of day for transequatorial propagation?

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

15. - E3C08

What does the space weather term G5 mean?

Select	Answer
A	Moderate solar wind
B	Waning sunspot numbers
C	An extreme geomagnetic storm
D	Very low solar activity

16. - E4A05

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

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

17. - E4B04

Which S parameter represents input port return loss or reflection coefficient (equivalent to VSWR)?

Select	Answer
A	S12
B	S11
C	S21
D	S22

18. - E4C05

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

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

19. - E4D09

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

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

20. - E4E09

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

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

21. - E5A09

How is the Q of an RLC parallel resonant circuit calculated?

Select	Answer
A	Resistance divided by the reactance of either the inductance or capacitance
B	Reactance of the inductance multiplied by the reactance of the capacitance
C	Reactance of either the inductance or capacitance multiplied by the resistance
D	Reactance of either the inductance or capacitance divided by the resistance

22. - E5B09

What is the relationship between the AC current through a capacitor and the voltage across a capacitor?

Select	Answer
A	Current leads voltage by 90 degrees
B	Voltage leads current by 90 degrees
C	Voltage and current are in phase
D	Voltage and current are 180 degrees out of phase

23. - E5C04

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

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

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	0.5
B	0.866
C	1.414
D	1.73

25. - E6A09

What is a depletion-mode FET?

Select	Answer
A	Any FET for which holes are the majority carriers
B	An FET that exhibits a current flow between source and drain when no gate voltage is applied
C	An FET that has no current flow between source and drain when no gate voltage is applied
D	Any FET without a channel

26. - E6B02

What is an important characteristic of a Schottky diode as compared to an ordinary silicon diode when used as a power supply rectifier?

Select	Answer
A	Much higher reverse voltage breakdown
B	Longer carrier retention time
C	More constant reverse avalanche voltage
D	Less forward voltage drop

27. - E6C04

Which of the following is an advantage of BiCMOS logic?

Select	Answer
A	Its simplicity results in much less expensive devices than standard CMOS
B	It is immune to electrostatic damage
C	All these choices are correct
D	It has the high input impedance of CMOS and the low output impedance of bipolar transistors

28. - E6D12

What is inductor saturation?

Select	Answer
A	Adjacent inductors become over-coupled
B	The inductor's voltage rating is exceeded causing a flashover
C	The ability of the inductor's core to store magnetic energy has been exceeded
D	The inductor windings are over-coupled

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	Surface mount
C	Axial lead
D	Radial lead

30. - E6F10

What is the most common type of photovoltaic cell used for electrical power generation?

Select	Answer
A	Copper oxide
B	Silicon
C	Selenium
D	Cadmium Sulfide

31. - E7A10

What is a truth table?

Select	Answer
A	A diagram showing logic states when the digital device output is true
B	A list of inputs and corresponding outputs for a digital device
C	A table of logic symbols that indicate the logic states of an op-amp
D	A table of logic symbols that indicate the high logic states of an op-amp

32. - E7B15

What is one way to prevent thermal runaway in a bipolar transistor amplifier?

Select	Answer
A	All these choices are correct
B	Use a resistor in series with the emitter
C	Select transistors with high beta
D	Neutralization

33. - E7C12

What is one advantage of a Pi-matching network over an L-matching network consisting of a single inductor and a single capacitor?

Select	Answer
A	Pi-networks are more stable
B	The Q of Pi-networks can be controlled
C	L-networks cannot perform impedance transformation
D	Pi-networks provide balanced input and output

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	Prevention of battery undercharge
C	Matching of day and night charge rates
D	Control of electrolyte levels during battery discharge

35. - E7E11

Which type of detector circuit is used for demodulating SSB signals?

Select	Answer
A	Phase detector
B	Discriminator
C	Phase comparator
D	Product detector

36. - E7F04

What is a common method of generating an SSB signal using digital signal processing?

Select	Answer
A	Varying quartz crystal characteristics emulated in digital form
B	Signals are combined in quadrature phase relationship
C	A frequency synthesizer removes the unwanted sidebands
D	Mixing products are converted to voltages and subtracted by adder circuits

37. - E7G04

What is meant by the "op-amp input offset voltage"?

Select	Answer
A	The difference between the output voltage of the op-amp and the input voltage required in the immediately following stage
B	The differential input voltage needed to bring the open loop output voltage to zero
C	The output voltage of the op-amp minus its input voltage
D	The potential between the amplifier input terminals of the op-amp in an open loop condition

38. - E7H06

Which of the following oscillator circuits are commonly used in VFOs?

Select	Answer
A	Armstrong and deForest
B	Colpitts and Hartley
C	Pierce and Zener
D	Negative feedback and balanced feedback

39. - E8A04

What is "dither" with respect to analog-to-digital converters?

Select	Answer
A	A method of decimation by randomly skipping samples
B	An abnormal condition where the converter cannot settle on a value to represent the signal
C	A small amount of noise added to the input signal to allow more precise representation of a signal over time
D	An error caused by irregular quantization step size

40. - E8B09

What is deviation ratio?

Select	Answer
A	The ratio of the maximum carrier frequency deviation to the highest audio modulating frequency
B	The ratio of the audio modulating frequency to the center carrier frequency
C	The ratio of the highest audio modulating frequency to the average audio modulating frequency
D	The ratio of the carrier center frequency to the audio modulating frequency

41. - E8C04

What technique minimizes the bandwidth of a PSK31 signal?

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

42. - E8D05

What is the most common method of reducing key clicks?

Select	Answer
A	Low-pass filters at the transmitter output
B	Increase keying waveform rise and fall times
C	High-pass filters at the transmitter output
D	Reduce keying waveform rise and fall times

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	3.85 dB
B	8.15 dB
C	6.0 dB
D	2.79 dB

44. - E9B02

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

Select	Answer
A	14 dB
B	36 dB
C	18 dB
D	24 dB

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

46. - E9D11

Which of the following conductors would be best for minimizing losses in a station's RF ground system?

Select	Answer
A	Wide flat copper strap
B	Stranded wire
C	Solid wire
D	Resistive wire, such as spark plug wire

47. - E9E05

How must an antenna's driven element be tuned to use a hairpin matching system?

Select	Answer
A	The driven element radiation resistance must be higher than the characteristic impedance of the transmission line
B	The driven element reactance must be capacitive
C	The driven element resonance must be lower than the operating frequency
D	The driven element reactance must be inductive

48. - E9F01

What is the velocity factor of a transmission line?

Select	Answer
A	The index of shielding for coaxial cable
B	The ratio of the characteristic impedance of the line to the terminating impedance
C	The velocity of the wave in the transmission line multiplied by the velocity of light in a vacuum
D	The velocity of the wave in the transmission line divided by the velocity of light in a vacuum

49. - E9G02

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

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

50. - E9H08

What is the function of a sense antenna?

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

Figure E9-1