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	300 to 3000 MHz
B	30 to 300 MHz
C	3 to 30 MHz
D	300 kHz to 3 MHz

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 station must have a power supply that is completely independent of the main ship or aircraft power supply
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 operator must have an FCC Marine or Aircraft endorsement on his or her amateur license
D	Its operation must be approved by the master of the ship or the pilot in command of the aircraft

3. - E1B08

What limitations may the FCC place on an amateur station if its signal causes interference to domestic broadcast reception, assuming that the receivers involved are of good engineering design?

Select	Answer
A	The amateur station must cease operation on all frequencies above 30 MHz
B	The amateur station must avoid transmitting during certain hours on frequencies that cause the interference
C	The amateur station must cease operation on all frequencies below 30 MHz
D	The amateur station must cease operation

4. - E1C07

At what level below a signal's mean power level is its bandwidth determined according to FCC rules?

Select	Answer
A	23 dB
B	6 dB
C	3 dB
D	26 dB

5. - E1D09

Which UHF amateur bands have frequencies authorized for space stations?

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

6. - E1E06

Who is responsible for the proper conduct and necessary supervision during an amateur operator license examination session?

Select	Answer
A	The VEC coordinating the session
B	The VE session manager
C	The FCC
D	Each administering VE

7. - E1F04

Which of the following geographic descriptions approximately describes "Line A"?

Select	Answer
A	A line roughly parallel to and north of the border between the U.S. and Mexico
B	A line roughly parallel to and south of the border between the U.S. and Canada
C	A line roughly parallel to and east of the U.S. Pacific coastline
D	A line roughly parallel to and west of the U.S. Atlantic coastline

8. - E2A08

Why should effective radiated power to a satellite that uses a linear transponder be limited?

Select	Answer
A	To prevent the satellite from emitting out-of-band signals
B	To avoid interfering with terrestrial QSOs
C	To avoid reducing the downlink power to all other users
D	To prevent creating errors in the satellite telemetry

9. - E2B10

What aspect of an analog slow-scan television signal encodes the brightness of the picture?

Select	Answer
A	Tone amplitude
B	Sync amplitude
C	Tone frequency
D	Sync frequency

10. - E2C09

What type of equipment is commonly used to implement an amateur radio mesh network?

Select	Answer
A	A 440 MHz transceiver with a 9600 baud modem
B	A wireless router running custom firmware
C	An optical cable connection between the USB ports of 2 separate computers
D	A 2 meter VHF transceiver with a 1200 baud modem

11. - E2D01

Which of the following digital modes is designed for meteor scatter communications?

Select	Answer
A	Hellschreiber
B	WSPR
C	APRS
D	MSK144

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	It depends on the lunar phase
D	Alternating transmissions at 7.5 second intervals

13. - E3A07

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

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

14. - E3B09

At what time of year is sporadic E propagation most likely to occur?

Select	Answer
A	Around the equinoxes, especially the spring equinox
B	Around the solstices, especially the summer solstice
C	Around the equinoxes, especially the fall equinox
D	Around the solstices, especially the winter solstice

15. - E3C07

Which of the following descriptors indicates the greatest solar flare intensity?

Select	Answer
A	Class B
B	Class M
C	Class X
D	Class A

16. - E4A03

Which of the following test instruments is used to display spurious signals and/or intermodulation distortion products generated by an SSB transmitter?

Select	Answer
A	A time-domain reflectometer
B	A spectrum analyzer
C	A logic analyzer
D	A wattmeter

17. - E4B03

Which S parameter is equivalent to forward gain?

Select	Answer
A	S22
B	S21
C	S11
D	S12

18. - E4C12

Which of the following has the largest effect on an SDR receiver's dynamic range?

Select	Answer
A	RAM speed used for data storage
B	Anti-aliasing input filter bandwidth
C	CPU register width in bits
D	Analog-to-digital converter sample width in bits

19. - E4D11

Why are odd-order intermodulation products, created within a receiver, of particular interest compared to other products?

Select	Answer
A	Odd-order intermodulation produces three products for every input signal within the band of interest
B	Odd-order products of two signals in the band of interest are also likely to be within the band
C	Odd-order products are an indication of poor image rejection
D	Odd-order products overload the IF filters

20. - E4E01

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

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

21. - E5A13

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

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

22. - E5B02

What letter is commonly used to represent susceptance?

Select	Answer
A	Y
B	G
C	B
D	X

23. - E5C12

Which point on Figure E5-1 best represents the impedance of a series circuit consisting of a 300-ohm resistor and a 19-picofarad capacitor at 21.200 MHz?

Select	Answer
A	Point 3
B	Point 1
C	Point 8
D	Point 7

24. - E5D06

In what direction is the magnetic field oriented about a conductor in relation to the direction of electron flow?

Select	Answer
A	In the same direction as the current
B	In a circle around the conductor
C	In all directions; omni-directional
D	In a direction opposite to the current

25. - E6A12

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

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

26. - E6B03

What type of bias is required for an LED to emit light?

Select	Answer
A	Zero bias
B	Inductive bias
C	Reverse bias
D	Forward bias

27. - E6C08

In Figure E6-3, what is the schematic symbol for a NAND gate?

Select	Answer
A	4
B	2
C	1
D	3

28. - E6D11

Which type of core material decreases inductance when inserted into a coil?

Select	Answer
A	Brass
B	Powdered iron
C	Ceramic
D	Ferrite

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
C	Silicon nitride
D	Gallium nitride

30. - E6F03

What is the most common configuration of an optoisolator or optocoupler?

Select	Answer
A	An LED and a phototransistor
B	A lens and a photomultiplier
C	An amplitude modulated helium-neon laser
D	A frequency modulated helium-neon laser

31. - E7A10

What is a truth table?

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

32. - E7B15

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

Select	Answer
A	Select transistors with high beta
B	All these choices are correct
C	Use a resistor in series with the emitter
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	The Q of Pi-networks can be controlled
B	Pi-networks are more stable
C	L-networks cannot perform impedance transformation
D	Pi-networks provide balanced input and output

34. - E7D14

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

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

35. - E7E10

How does a diode envelope detector function?

Select	Answer
A	By breakdown of the Zener voltage
B	By mixing signals with noise in the transition region of the diode
C	By sensing the change of reactance in the diode with respect to frequency
D	By rectification and filtering of RF signals

36. - E7F13

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

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

37. - E7G02

What is ringing in a filter?

Select	Answer
A	Partial cancellation of the signal over a range of frequencies
B	Undesired oscillations added to the desired signal
C	A reduction in high frequency response
D	An echo caused by a long time delay

38. - E7H14

What is a phase-locked loop circuit?

Select	Answer
A	An electronic servo loop consisting of a ratio detector, reactance modulator, and voltage-controlled oscillator
B	An electronic servo loop consisting of a phase detector, a low-pass filter, a voltage-controlled oscillator, and a stable reference oscillator
C	An electronic circuit also known as a monostable multivibrator
D	An electronic circuit consisting of a precision push-pull amplifier with a differential input

39. - E8A09

How many different input levels can be encoded by an analog-to-digital converter with 8-bit resolution?

Select	Answer
A	8 multiplied by the gain of the input amplifier
B	256
C	256 divided by the gain of the input amplifier
D	8

40. - E8B03

What is the modulation index of an FM-phone signal having a maximum frequency deviation of 3000 Hz either side of the carrier frequency when the modulating frequency is 1000 Hz?

Select	Answer
A	0.3
B	3
C	3000
D	1000

41. - E8C03

Why should phase-shifting of a PSK signal be done at the zero crossing of the RF signal?

Select	Answer
A	All these choices are correct
B	To improve carrier suppression
C	To simplify modulation
D	To minimize bandwidth

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

43. - E9A09

What is antenna efficiency?

Select	Answer
A	Effective radiated power divided by transmitter output
B	Radiation resistance divided by total resistance
C	Radiation resistance divided by transmission resistance
D	Total resistance divided by radiation resistance

44. - E9B11

What is a disadvantage of decreasing the number of wire segments in an antenna model below 10 segments per half-wavelength?

Select	Answer
A	Ground conductivity will not be accurately modeled
B	The antenna will become mechanically unstable
C	The computed feed point impedance may be incorrect
D	The resulting design will favor radiation of harmonic energy

45. - E9C14

How does the performance of a horizontally polarized antenna mounted on the side of a hill compare with the same antenna mounted on flat ground?

Select	Answer
A	The main lobe takeoff angle decreases in the downhill direction
B	The horizontal beamwidth decreases in the downhill direction
C	The main lobe takeoff angle increases in the downhill direction
D	The horizontal beamwidth increases in the uphill direction

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 3 or 4 interconnected ground rods driven into the Earth
C	An electrically short connection to a metal water pipe
D	A 50-ohm resistor connected to ground

47. - E9E01

What system matches a higher-impedance transmission line to a lower-impedance antenna by connecting the line to the driven element in two places spaced a fraction of a wavelength each side of element center?

Select	Answer
A	The omega matching system
B	The delta matching system
C	The gamma matching system
D	The stub matching system

48. - E9F07

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

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

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 voltage axis
C	The current axis
D	The reactance axis

50. - E9H09

What is a Pennant antenna?

Select	Answer
A	A small, vertically oriented receiving antenna consisting of a triangular loop terminated in approximately 900 ohms
B	A stealth antenna built to look like a flagpole
C	A four-element, high-gain vertical array invented by George Pennant
D	A form of rhombic antenna terminated in a variable capacitor to provide frequency diversity

Figure E5-1

Figure E6-3

Figure E9-3