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. - E0A08

What does SAR measure?

Select	Answer
A	Synthetic Aperture Ratio of the human body
B	The rate of RF energy reflected from stationary terrain
C	The rate at which RF energy is absorbed by the body
D	Signal Amplification Rating

2. - E1A10

If an amateur station is installed aboard a ship or aircraft, what condition must be met before the station is operated?

Select	Answer
A	The amateur operator must have an FCC Marine or Aircraft endorsement on his or her amateur license
B	The amateur station operator must agree not to transmit when the main radio of the ship or aircraft is in use
C	The amateur station must have a power supply that is completely independent of the main ship or aircraft power supply
D	Its operation must be approved by the master of the ship or the pilot in command of the aircraft

3. - E1B02

Which of the following is an acceptable bandwidth for Digital Radio Mondiale (DRM) based voice or SSTV digital transmissions made on the HF amateur bands?

Select	Answer
A	10 kHz
B	3 kHz
C	15 kHz
D	20 kHz

4. - E1C02

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

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

5. - E1D08

Which VHF amateur bands have frequencies authorized for space stations?

Select	Answer
A	6 meters and 2 meters
B	2 meters
C	2 meters and 1.25 meters
D	6 meters, 2 meters, and 1.25 meters

6. - E1E09

What may be the penalty for a VE who fraudulently administers or certifies an examination?

Select	Answer
A	A sentence of up to one year in prison
B	A fine of up to $1000 per occurrence
C	All these choices are correct
D	Revocation of the VE's amateur station license grant and the suspension of the VE's amateur operator license grant

7. - E1F11

Which of the following best describes one of the standards that must be met by an external RF power amplifier if it is to qualify for a grant of FCC certification?

Select	Answer
A	It must exhibit a gain of 0 dB or less over its full output range
B	It must be capable of external RF switching between its input and output networks
C	It must satisfy the FCC's spurious emission standards when operated at the lesser of 1500 watts or its full output power
D	It must produce full legal output when driven by not more than 5 watts of mean RF input power

8. - E2A10

What type of satellite appears to stay in one position in the sky?

Select	Answer
A	Geomagnetic
B	LEO
C	HEO
D	Geostationary

9. - E2B12

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

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

10. - E2C12

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

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

11. - E2D11

Which of the following data are used by the APRS network to communicate station location?

Select	Answer
A	Latitude and longitude
B	Polar coordinates
C	Radio direction finding spectrum analysis
D	Time and frequency

12. - E2E11

What is the difference between direct FSK and audio FSK?

Select	Answer
A	Direct FSK applies the data signal to the transmitter VFO, while AFSK transmits tones via phone
B	Direct FSK can transmit faster baud rates
C	Only direct FSK can be decoded by computer
D	Direct FSK occupies less bandwidth

13. - E3A07

Atmospheric ducts capable of propagating microwave signals often form over what geographic feature?

Select	Answer
A	Mountain ranges
B	Urban areas
C	Bodies of water
D	Forests

14. - E3B12

What is the primary characteristic of chordal hop propagation?

Select	Answer
A	Signals reflected back toward the transmitting station
B	Propagation away from the great circle bearing between stations
C	Successive ionospheric refractions without an intermediate reflection from the ground
D	Propagation across the geomagnetic equator

15. - E3C08

What does the space weather term G5 mean?

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

16. - E4A09

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

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

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. - E4C13

How does a narrow-band roofing filter affect receiver performance?

Select	Answer
A	It improves sensitivity by reducing front end noise
B	All these choices are correct
C	It improves intelligibility by using low Q circuitry to reduce ringing
D	It improves dynamic range by attenuating strong signals near the receive frequency

19. - E4D01

What is meant by the blocking dynamic range of a receiver?

Select	Answer
A	The minimum difference in dB between the levels of two FM signals that will cause one signal to block the other
B	The minimum difference in dB between two signals which produce third-order intermodulation products greater than the noise floor
C	The difference in dB between the noise floor and the third-order intercept point
D	The difference in dB between the noise floor and the level of an incoming signal that will cause 1 dB of gain compression

20. - E4E01

What problem can occur when using an automatic notch filter (ANF) to remove interfering carriers while receiving CW signals?

Select	Answer
A	Removal of the CW signal as well as the interfering carrier
B	Received CW signals will appear to be modulated at the DSP clock frequency
C	Any nearby signal passing through the DSP system will overwhelm the desired signal
D	Ringing in the DSP filter will completely remove the spaces between the CW characters

21. - E5A02

What is resonance in an LC or RLC circuit?

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

22. - E5B09

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

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

23. - E5C02

How are impedances described in polar coordinates?

Select	Answer
A	By X and R values
B	By Y and G values
C	By real and imaginary parts
D	By phase angle and magnitude

24. - E5D09

What happens to reactive power in an AC circuit that has both ideal inductors and ideal capacitors?

Select	Answer
A	It is dissipated in the formation of inductive and capacitive fields
B	It is repeatedly exchanged between the associated magnetic and electric fields, but is not dissipated
C	It is dissipated as heat in the circuit
D	It is dissipated as kinetic energy in the circuit

25. - E6A01

In what application is gallium arsenide used as a semiconductor material?

Select	Answer
A	In microwave circuits
B	In high-power audio circuits
C	In very low-frequency RF circuits
D	In high-current rectifier circuits

26. - E6B07

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

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

27. - E6C07

What best describes a pull-up or pull-down resistor?

Select	Answer
A	A resistor connected to the positive or negative supply line used to establish a voltage when an input or output is an open circuit
B	A resistor connected to an op-amp output that prevents signals from exceeding the power supply voltage
C	A resistor in a keying circuit used to reduce key clicks
D	A resistor that ensures that an oscillator frequency does not drift

28. - E6D04

Which materials are commonly used as a core in an inductor?

Select	Answer
A	Ferrite and brass
B	Polystyrene and polyethylene
C	Teflon and Delrin
D	Cobalt and aluminum

29. - E6E12

Why are DIP through-hole package ICs not typically used at UHF and higher frequencies?

Select	Answer
A	Excessive lead length
B	Epoxy coating is conductive above 300 MHz
C	Unsuitable for combining analog and digital signals
D	Too many pins

30. - E6F04

What is the photovoltaic effect?

Select	Answer
A	The conversion of electrical energy to mechanical energy
B	The tendency of a battery to discharge when exposed to light
C	The conversion of light to electrical energy
D	The conversion of voltage to current when exposed to light

31. - E7A04

How many flip-flops are required to divide a signal frequency by 4?

Select	Answer
A	8
B	4
C	2
D	1

32. - E7B01

For what portion of the signal cycle does each active element in a push-pull Class AB amplifier conduct?

Select	Answer
A	Exactly 180 degrees
B	More than 180 degrees but less than 360 degrees
C	The entire cycle
D	Less than 180 degrees

33. - E7C06

What are the distinguishing features of an elliptical filter?

Select	Answer
A	Extremely sharp cutoff with one or more notches in the stop band
B	Gradual passband rolloff with minimal stop band ripple
C	Extremely flat response over its pass band with gradually rounded stop band corners
D	Gradual passband rolloff with extreme stop band ripple

34. - E7D14

What is the purpose of connecting equal-value resistors across power supply filter capacitors connected in series?

Select	Answer
A	Provide a minimum load on the supply
B	Equalize the voltage across each capacitor
C	All these choices are correct
D	Discharge the capacitors when voltage is removed

35. - E7E09

What occurs when an excessive amount of signal energy reaches a mixer circuit?

Select	Answer
A	Mixer blanking occurs
B	Spurious mixer products are generated
C	Automatic limiting occurs
D	A beat frequency is generated

36. - E7F01

What is meant by direct digital conversion as applied to software defined radios?

Select	Answer
A	Incoming RF is digitized by an analog-to-digital converter without being mixed with a local oscillator signal
B	Software is converted from source code to object code during operation of the receiver
C	Incoming RF is converted to a control voltage for a voltage controlled oscillator
D	A switching mixer is used to generate I and Q signals directly from the RF input

37. - E7G08

How does the gain of an ideal operational amplifier vary with frequency?

Select	Answer
A	It increases linearly with increasing frequency
B	It does not vary with frequency
C	It decreases logarithmically with increasing frequency
D	It decreases linearly with increasing frequency

38. - E7H07

How can an oscillator's microphonic responses be reduced?

Select	Answer
A	Reduce noise on the oscillator's power supply
B	Use NP0 capacitors
C	Increase the bias voltage
D	Mechanically isolate the oscillator circuitry from its enclosure

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	Differential analysis
B	Fourier analysis
C	Vector analysis
D	Numerical analysis

40. - E8B10

What is frequency division multiplexing?

Select	Answer
A	Two or more information streams are merged into a digital combiner, which then pulse position modulates the transmitter
B	The transmitted signal is divided into packets of information
C	The transmitted signal jumps from band to band at a predetermined rate
D	Two or more information streams are merged into a baseband, which then modulates the transmitter

41. - E8C01

How is Forward Error Correction implemented?

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

42. - E8D03

How does the spread spectrum technique of frequency hopping work?

Select	Answer
A	If interference is detected by the receiver it will signal the transmitter to change frequencies
B	If interference is detected by the receiver it will signal the transmitter to wait until the frequency is clear
C	A binary bit stream is used to shift the phase of an RF carrier very rapidly in a pseudorandom sequence
D	The frequency of the transmitted signal is changed very rapidly according to a pseudorandom sequence also used by the receiving station

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	1977 watts
C	420 watts
D	78.7 watts

44. - E9B04

What is the front-to-back ratio of the radiation pattern shown in Figure E92?

Select	Answer
A	38 dB
B	15 dB
C	28 dB
D	3 dB

45. - E9C04

What happens to the radiation pattern of an unterminated long wire antenna as the wire length is increased?

Select	Answer
A	The lobes align more in the direction of the wire
B	The vertical angle increases
C	The front-to-back ratio decreases
D	The lobes become more perpendicular to the wire

46. - E9D12

Which of the following would provide the best RF ground for your station?

Select	Answer
A	An electrically short connection to 3 or 4 interconnected ground rods via a series RF choke
B	An electrically short connection to a metal water pipe
C	An electrically short connection to 3 or 4 interconnected ground rods driven into the Earth
D	A 50-ohm resistor connected to ground

47. - E9E04

What is the purpose of the series capacitor in a gamma-type antenna matching network?

Select	Answer
A	To provide a rejection notch that prevents the radiation of harmonics
B	To transform the antenna impedance to a higher value
C	To provide DC isolation between the feed line and the antenna
D	To cancel the inductive reactance of the matching network

48. - E9F09

What is the approximate physical length of a foam polyethylene dielectric coaxial transmission line that is electrically 1/4 wavelength long at 7.2 MHz?

Select	Answer
A	5.2 meters
B	10.4 meters
C	6.9 meters
D	8.3 meters

49. - E9G07

On the Smith chart shown in Figure E9-3, what is the only straight line shown?

Select	Answer
A	The resistance axis
B	The current axis
C	The reactance axis
D	The voltage axis

50. - E9H10

How can the output voltage of a multiple-turn receiving loop antenna be increased?

Select	Answer
A	By winding adjacent turns in opposing directions
B	By reducing the permeability of the loop shield
C	By utilizing high impedance wire for the coupling loop
D	By increasing the number of turns and/or the area

Figure E9-3