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

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1. - E0A08

What does SAR measure?

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

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

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	20 kHz
D	15 kHz

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 63 dB below
B	At least 73 dB below
C	At least 53 dB below
D	At least 43 dB below

5. - E1D10

Which amateur stations are eligible to be telecommand stations of space stations (subject to the privileges of the class of operator license held by the control operator of the station)?

Select	Answer
A	All these choices are correct
B	Any amateur station so designated by the space station licensee
C	Any amateur station so designated by the ITU
D	Any amateur station designated by NASA

6. - E1E04

Which of the following best describes the Volunteer Examiner accreditation process?

Select	Answer
A	The amateur operator applying must pass a VE examination administered by the FCC Enforcement Bureau
B	The prospective VE obtains accreditation from the FCC
C	Each General, Advanced and Amateur Extra Class operator is automatically accredited as a VE when the license is granted
D	The procedure by which a VEC confirms that the VE applicant meets FCC requirements to serve as an examiner

7. - E1F06

Under what circumstances might the FCC issue a Special Temporary Authority (STA) to an amateur station?

Select	Answer
A	To provide additional spectrum for personal use
B	To provide for experimental amateur communications
C	To allow regular operation on Land Mobile channels
D	To provide temporary operation while awaiting normal licensing

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. - 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	A special front end limiter
B	A special IF converter
C	A special notch filter to remove synchronization pulses
D	No other hardware is needed

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

11. - E2D02

Which of the following is a good technique for making meteor scatter contacts?

Select	Answer
A	Short transmissions with rapidly repeated call signs and signal reports
B	15-second timed transmission sequences with stations alternating based on location
C	All these choices are correct
D	Use of special digital modes

12. - E2E03

How is the timing of FT4 contacts organized?

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

13. - E3A08

When a meteor strikes the Earth's atmosphere, a cylindrical region of free electrons is formed at what layer of the ionosphere?

Select	Answer
A	The F2 layer
B	The F1 layer
C	The D layer
D	The E layer

14. - E3B11

At what time of day can sporadic E propagation occur?

Select	Answer
A	Only in hours of darkness
B	Any time
C	Only around sunset and sunrise
D	Only around sunset

15. - E3C04

What does the value of Bz (B sub Z) represent?

Select	Answer
A	Geomagnetic field stability
B	Direction and strength of the interplanetary magnetic field
C	Duration of long-delayed echoes
D	Critical frequency for vertical transmissions

16. - E4A02

Which of the following parameters does a spectrum analyzer display on the vertical and horizontal axes?

Select	Answer
A	SWR and time
B	SWR and frequency
C	RF amplitude and frequency
D	RF amplitude and time

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	125 watts
B	75 watts
C	25 watts
D	100 watts

18. - E4C02

Which of the following receiver circuits can be effective in eliminating interference from strong out-of-band signals?

Select	Answer
A	A notch filter
B	A front-end filter or pre-selector
C	A narrow IF filter
D	A properly adjusted product detector

19. - E4D08

What causes intermodulation in an electronic circuit?

Select	Answer
A	Too little gain
B	Positive feedback
C	Nonlinear circuits or devices
D	Lack of neutralization

20. - E4E06

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

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

21. - E5A13

What is an effect of increasing Q in a series resonant circuit?

Select	Answer
A	Parasitic effects are minimized
B	Phase shift can become uncontrolled
C	Fewer components are needed for the same performance
D	Internal voltages increase

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 and current are in phase
C	Voltage and current are 180 degrees out of phase
D	Voltage leads current by 90 degrees

23. - E5C02

How are impedances described in polar coordinates?

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

24. - E5D07

How many watts are consumed in a circuit having a power factor of 0.71 if the apparent power is 500VA?

Select	Answer
A	704 W
B	1.42 mW
C	355 W
D	252 W

25. - E6A12

Why do many MOSFET devices have internally connected Zener diodes on the gates?

Select	Answer
A	To reduce the chance of static damage to the gate
B	To provide a voltage reference for the correct amount of reverse-bias gate voltage
C	To keep the gate voltage within specifications and prevent the device from overheating
D	To protect the substrate from excessive voltages

26. - E6B06

Which of the following is a common use of a Schottky diode?

Select	Answer
A	As a constant voltage reference in a power supply
B	As a variable capacitance in an automatic frequency control circuit
C	As a VHF/UHF mixer or detector
D	As a rectifier in high current power supplies

27. - E6C11

In Figure E6-3, what is the schematic symbol for the NOT operation (inverter)?

Select	Answer
A	2
B	4
C	6
D	5

28. - E6D03

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

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

29. - E6E10

What advantage does surface-mount technology offer at RF compared to using through-hole components?

Select	Answer
A	Smaller circuit area
B	All these choices are correct
C	Components have less parasitic inductance and capacitance
D	Shorter circuit-board traces

30. - E6F04

What is the photovoltaic effect?

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

31. - E7A11

What type of logic defines "1" as a high voltage?

Select	Answer
A	Assertive Logic
B	Positive Logic
C	Reverse Logic
D	Negative logic

32. - E7B14

Why are switching amplifiers more efficient than linear amplifiers?

Select	Answer
A	Linear amplifiers have high gain resulting in higher harmonic content
B	The power transistor is at saturation or cutoff most of the time
C	Switching amplifiers use push-pull circuits
D	Switching amplifiers operate at higher voltages

33. - E7C10

Which of the following filters would be the best choice for use in a 2 meter band repeater duplexer?

Select	Answer
A	An L-C filter
B	A crystal filter
C	A cavity filter
D	A DSP filter

34. - E7D05

Which of the following types of linear voltage regulator places a constant load on the unregulated voltage source?

Select	Answer
A	A series regulator
B	A shunt regulator
C	A constant current source
D	A shunt current source

35. - E7E04

What is one way a single-sideband phone signal can be generated?

Select	Answer
A	By using a reactance modulator followed by a mixer
B	By driving a product detector with a DSB signal
C	By using a loop modulator followed by a mixer
D	By using a balanced modulator followed by a filter

36. - E7F09

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

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

37. - E7G10

What absolute voltage gain can be expected from the circuit in Figure E7-3 when R1 is 1800 ohms and RF is 68 kilohms?

Select	Answer
A	76
B	0.03
C	1
D	38

38. - E7H13

Which of the following is a technique for providing highly accurate and stable oscillators needed for microwave transmission and reception?

Select	Answer
A	Use a GPS signal reference
B	All these choices are correct
C	Use a rubidium stabilized reference oscillator
D	Use a temperature-controlled high Q dielectric resonator

39. - E8A04

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

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

40. - E8B01

What is the modulation index of an FM signal?

Select	Answer
A	The type of modulation used by the transmitter
B	The ratio of modulating signal amplitude to frequency deviation
C	The bandwidth of the transmitted signal divided by the modulating signal frequency
D	The ratio of frequency deviation to modulating signal frequency

41. - E8C07

What is the bandwidth of a 4800-Hz frequency shift, 9600-baud ASCII FM transmission?

Select	Answer
A	5.76 kHz
B	15.36 kHz
C	9.6 kHz
D	4.8 kHz

42. - E8D07

What is a common cause of overmodulation of AFSK signals?

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

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	78.7 watts
B	1977 watts
C	286 watts
D	420 watts

44. - E9B06

What is the elevation angle of peak response in the antenna radiation pattern shown in Figure E9-2?

Select	Answer
A	25 degrees
B	45 degrees
C	75 degrees
D	7.5 degrees

45. - E9C07

What is the approximate feed point impedance at the center of a two-wire folded dipole antenna?

Select	Answer
A	450 ohms
B	50 ohms
C	72 ohms
D	300 ohms

46. - E9D02

How can linearly polarized Yagi antennas be used to produce circular polarization?

Select	Answer
A	Arrange two Yagis collinear to each other with the driven elements fed 180 degrees out of phase
B	Arrange two Yagis perpendicular to each other with the driven elements at the same point on the boom fed 90 degrees out of phase
C	Stack two Yagis fed in phase to form an array with the respective elements in parallel planes
D	Stack two Yagis fed 90 degrees out of phase to form an array with the respective elements in parallel planes

47. - E9E09

Which of the following is used to shunt-feed a grounded tower at its base?

Select	Answer
A	Double-bazooka match
B	Gamma match
C	Hairpin match
D	All these choices are correct

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	An inductive reactance
C	The same as the characteristic impedance of the line
D	Zero

49. - E9G03

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

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

50. - E9H03

What is Receiving Directivity Factor (RDF)?

Select	Answer
A	Forward gain compared to the gain in the reverse direction
B	Relative directivity compared to isotropic
C	Forward gain compared to average gain over the entire hemisphere
D	Relative directivity compared to a dipole

Figure E6-3

Figure E7-3

Figure E9-2