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

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1. - E0A03

Over what range of frequencies are the FCC human body RF exposure limits most restrictive?

Select	Answer
A	30 to 300 MHz
B	3 to 30 MHz
C	300 to 3000 MHz
D	300 kHz to 3 MHz

2. - E1A06

Where must the carrier frequency of a CW signal be set to comply with FCC rules for 60 meter operation?

Select	Answer
A	At the center frequency of the channel
B	On any frequency where the signal's sidebands are within the channel
C	At the highest frequency of the channel
D	At the lowest frequency of the channel

3. - E1B07

To what type of regulations does PRB-1 apply?

Select	Answer
A	FAA tower height limits
B	Use of wireless devices in vehicles
C	State and local zoning
D	Homeowners associations

4. - E1C12

On what portion of the 630 meter band are phone emissions permitted?

Select	Answer
A	Only the bottom 3 kHz
B	Only the top 3 kHz
C	The entire band
D	None

5. - E1D03

What is a space telecommand station?

Select	Answer
A	An amateur station located on the surface of the Earth for communication with other Earth stations by means of Earth satellites
B	An amateur station that receives telemetry from a satellite or balloon more than 50 kilometers above the surface of the Earth
C	An amateur station that transmits communications to initiate, modify or terminate functions of a space station
D	An amateur station located in a satellite or a balloon more than 50 kilometers above the surface of the Earth

6. - E1E05

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

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

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 produce full legal output when driven by not more than 5 watts of mean RF input power
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 be capable of external RF switching between its input and output networks

8. - E2A05

What do the letters in a satellite's mode designator specify?

Select	Answer
A	The uplink and downlink frequency ranges
B	Power limits for uplink and downlink transmissions
C	The polarization of uplink and downlink signals
D	The location of the ground control station

9. - E2B05

Which of the following describes the use of vestigial sideband in analog fast-scan TV transmissions?

Select	Answer
A	Vestigial sideband reduces bandwidth while allowing for simple video detector circuitry
B	The vestigial sideband contains chroma information
C	The vestigial sideband carries the audio information
D	Vestigial sideband provides high frequency emphasis to sharpen the picture

10. - E2C12

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

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

11. - E2D11

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

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

12. - E2E08

Which of the following HF digital modes can be used to transfer binary files?

Select	Answer
A	AMTOR
B	RTTY
C	PACTOR
D	Hellschreiber

13. - E3A12

What is the cause of auroral activity?

Select	Answer
A	An extreme low-pressure area in the polar regions
B	The interaction in the F2 layer between the solar wind and the Van Allen belt
C	The interaction in the E layer of charged particles from the Sun with the Earth's magnetic field
D	Meteor showers concentrated in the extreme northern and southern latitudes

14. - E3B02

What is the approximate maximum range for signals using transequatorial propagation?

Select	Answer
A	2500 miles
B	7500 miles
C	5000 miles
D	1000 miles

15. - E3C04

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

Select	Answer
A	Duration of long-delayed echoes
B	Geomagnetic field stability
C	Direction and strength of the interplanetary magnetic field
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	RF amplitude and frequency
B	RF amplitude and time
C	SWR and frequency
D	SWR and time

17. - E4B01

Which of the following factors most affects the accuracy of a frequency counter?

Select	Answer
A	Input attenuator accuracy
B	Decade divider accuracy
C	Temperature coefficient of the logic
D	Time base accuracy

18. - E4C15

What is reciprocal mixing?

Select	Answer
A	Two digital signals combining from alternate time slots
B	Two out-of-band signals mixing to generate an in-band spurious signal
C	In-phase signals cancelling in a mixer resulting in loss of receiver sensitivity
D	Local oscillator phase noise mixing with adjacent strong signals to create interference to desired signals

19. - E4D05

What transmitter frequencies would cause an intermodulation-product signal in a receiver tuned to 146.70 MHz when a nearby station transmits on 146.52 MHz?

Select	Answer
A	173.35 MHz and 139.40 MHz
B	146.10 MHz and 147.30 MHz
C	146.88 MHz and 146.34 MHz
D	146.34 MHz and 146.61 MHz

20. - E4E04

How can conducted and radiated noise caused by an automobile alternator be suppressed?

Select	Answer
A	By installing filter capacitors in series with the DC power lead and a blocking capacitor in the field lead
B	By installing a high-pass filter in series with the radio's power lead and a low-pass filter in parallel with the field lead
C	By connecting the radio's power leads directly to the battery and by installing coaxial capacitors in line with the alternator leads
D	By installing a noise suppression resistor and a blocking capacitor in both leads

21. - E5A01

What can cause the voltage across reactances in a series RLC circuit to be higher than the voltage applied to the entire circuit?

Select	Answer
A	Resonance
B	Capacitance
C	Conductance
D	Resistance

22. - E5B05

What happens to the magnitude of a pure reactance when it is converted to a susceptance?

Select	Answer
A	The sign is reversed
B	It is unchanged
C	It is shifted by 90 degrees
D	It becomes the reciprocal

23. - E5C05

What is the name of the diagram used to show the phase relationship between impedances at a given frequency?

Select	Answer
A	Phasor diagram
B	Far field diagram
C	Venn diagram
D	Near field diagram

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. - E6A11

In Figure E6-1, what is the schematic symbol for a P-channel junction FET?

Select	Answer
A	1
B	3
C	6
D	2

26. - E6B06

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

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

27. - E6C01

What is the function of hysteresis in a comparator?

Select	Answer
A	To increase the sensitivity
B	To cause the output to change states continually
C	To allow the comparator to be used with AC input signals
D	To prevent input noise from causing unstable output signals

28. - E6D13

What is the primary cause of inductor self-resonance?

Select	Answer
A	The skin effect
B	Inter-turn capacitance
C	Inductive kickback
D	Non-linear core hysteresis

29. - E6E12

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

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

30. - E6F01

What absorbs the energy from light falling on a photovoltaic cell?

Select	Answer
A	Protons
B	Photons
C	Holes
D	Electrons

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

32. - E7B07

Which of the following is a likely result when a Class C amplifier is used to amplify a single-sideband phone signal?

Select	Answer
A	Reduced intermodulation products
B	Signal distortion and excessive bandwidth
C	Signal inversion
D	Increased overall intelligibility

33. - E7C02

Which of the following is a property of a T-network with series capacitors and a parallel shunt inductor?

Select	Answer
A	It is a low-pass filter
B	It is a high-pass filter
C	It is a notch filter
D	It is a band-pass filter

34. - E7D06

What is the purpose of Q1 in the circuit shown in Figure E7-2?

Select	Answer
A	It provides a constant load for the voltage source
B	It provides negative feedback to improve regulation
C	It provides D1 with current
D	It controls the current supplied to the load

35. - E7E02

What is the function of a reactance modulator?

Select	Answer
A	To produce AM signals by using an electrically variable inductance or capacitance
B	To produce PM or FM signals by using an electrically variable inductance or capacitance
C	To produce PM signals by using an electrically variable resistance
D	To produce AM signals by using an electrically variable resistance

36. - E7F13

What is the function of taps in a digital signal processing filter?

Select	Answer
A	To reduce excess signal pressure levels
B	Provide access for debugging software
C	Select the point at which baseband signals are generated
D	Provide incremental signal delays for filter algorithms

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 potential between the amplifier input terminals of the op-amp in an open loop condition
C	The output voltage of the op-amp minus its input voltage
D	The differential input voltage needed to bring the open loop output voltage to zero

38. - E7H08

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

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

39. - E8A02

Which of the following is a type of analog-to-digital conversion?

Select	Answer
A	Level shifting
B	Harmonic regeneration
C	Successive approximation
D	Phase reversal

40. - E8B09

What is deviation ratio?

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

41. - E8C07

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

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

42. - E8D03

How does the spread spectrum technique of frequency hopping work?

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

43. - E9A04

Which of the following factors affect the feed point impedance of an antenna?

Select	Answer
A	The settings of an antenna tuner at the transmitter
B	Transmission line length
C	Antenna height
D	The input power level

44. - E9B03

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

Select	Answer
A	24 dB
B	12 dB
C	18 dB
D	14 dB

45. - E9C05

Which of the following is a type of OCFD antenna?

Select	Answer
A	A folded dipole center-fed with 300-ohm transmission line
B	A remotely tunable dipole antenna using orthogonally controlled frequency diversity
C	A multiband dipole antenna using one-way circular polarization for frequency diversity
D	A dipole fed approximately 1/3 the way from one end with a 4:1 balun to provide multiband operation

46. - E9D08

What happens as the Q of an antenna increases?

Select	Answer
A	SWR bandwidth increases
B	SWR bandwidth decreases
C	Gain is reduced
D	More common-mode current is present on the feed line

47. - E9E06

Which of these feed line impedances would be suitable for constructing a quarter-wave Q-section for matching a 100-ohm loop to 50-ohm feed line?

Select	Answer
A	450 ohms
B	75 ohms
C	62 ohms
D	50 ohms

48. - E9F07

How does ladder line compare to small-diameter coaxial cable such as RG-58 at 50 MHz?

Select	Answer
A	Smaller reflection coefficient
B	Lower loss
C	Higher SWR
D	Lower velocity factor

49. - E9G03

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

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

50. - E9H04

What is an advantage of placing a grounded electrostatic shield around a small loop direction-finding antenna?

Select	Answer
A	It increases signal strength by providing a better match to the feed line
B	It eliminates unbalanced capacitive coupling to the surroundings, improving the nulls
C	It eliminates tracking errors caused by strong out-of-band signals
D	It adds capacitive loading, increasing the bandwidth of the antenna

Figure E6-1

Figure E7-2

Figure E9-1