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. - E1A02

When using a transceiver that displays the carrier frequency of phone signals, which of the following displayed frequencies represents the lowest frequency at which a properly adjusted LSB emission will be totally within the band?

Select	Answer
A	The exact lower band edge
B	1 kHz above the lower band edge
C	3 kHz above the lower band edge
D	300 Hz above the lower band edge

3. - E1B11

What does PRB-1 require of regulations affecting amateur radio?

Select	Answer
A	No limitations may be placed on antenna size or placement
B	Reasonable accommodations of amateur radio must be made
C	Use of wireless devices in a vehicle is exempt from regulation
D	Amateur radio operations must be permitted in any private residence

4. - E1C03

How do the control operator responsibilities of a station under automatic control differ from one under local control?

Select	Answer
A	Under automatic control there is no control operator
B	Under local control there is no control operator
C	Under local control a control operator is not required to be present at a control point
D	Under automatic control the control operator is not required to be present at the control point

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

6. - E1E06

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

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

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

8. - E2A03

How is the signal inverted by an inverting linear transponder?

Select	Answer
A	The signal is passed through a mixer and the difference rather than the sum is transmitted
B	The signal is reduced to I and Q components and the Q component is filtered out
C	The signal is detected and remodulated on the reverse sideband
D	The signal is passed through a non-linear filter

9. - E2B03

How is an interlaced scanning pattern generated in a fast-scan (NTSC) television system?

Select	Answer
A	By scanning lines from left to right in one field and right to left in the next
B	By scanning two fields simultaneously
C	By scanning odd numbered lines in one field and even numbered lines in the next
D	By scanning each field from bottom to top

10. - E2C03

From which of the following bands is amateur radio contesting generally excluded?

Select	Answer
A	2 meters
B	33 centimeters
C	30 meters
D	6 meters

11. - E2D04

What technology is used to track, in real time, balloons carrying amateur radio transmitters?

Select	Answer
A	Doppler shift of beacon signals
B	Bandwidth compressed LORAN
C	Ultrasonics
D	APRS

12. - E2E09

Which of the following HF digital modes uses variable-length coding for bandwidth efficiency?

Select	Answer
A	PSK31
B	RTTY
C	PACTOR
D	MT63

13. - E3A10

Which type of atmospheric structure can create a path for microwave propagation?

Select	Answer
A	Wind shear
B	Dust devil
C	Temperature inversion
D	The jet stream

14. - E3B10

Why is chordal hop propagation desirable?

Select	Answer
A	Signals travel faster along ionospheric chords
B	The signal experiences less loss compared to multi-hop using Earth as a reflector
C	The MUF for chordal hop propagation is much lower than for normal skip propagation
D	Atmospheric noise is lower in the direction of chordal hop propagation

15. - E3C13

What type of polarization is best for ground-wave propagation?

Select	Answer
A	Circular
B	Elliptical
C	Vertical
D	Horizontal

16. - E4A09

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

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

17. - E4B10

Which of the following methods measures intermodulation distortion in an SSB transmitter?

Select	Answer
A	Modulate the transmitter using two AF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer
B	Modulate the transmitter using two RF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer
C	Modulate the transmitter using two AF signals having harmonically related frequencies and observe the RF output with a peak reading wattmeter
D	Modulate the transmitter using two RF signals having harmonically related frequencies and observe the RF output with a logic analyzer

18. - E4C05

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

Select	Answer
A	The minimum detectable signal as a function of receive frequency
B	The noise figure of a 1 Hz bandwidth receiver
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. - E4D06

What is the term for spurious signals generated by the combination of two or more signals in a non-linear device or circuit?

Select	Answer
A	Amplifier desensitization
B	Adjacent channel interference
C	Intermodulation
D	Neutralization

20. - E4E09

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

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

21. - E5A10

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

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

22. - E5B12

What is admittance?

Select	Answer
A	The inverse of impedance
B	The term for the gain of a field effect transistor
C	The inverse of Q factor
D	The turns ratio of a transformer

23. - E5C11

Which point in Figure E5-1 best represents the impedance of a series circuit consisting of a 300-ohm resistor and an 18-microhenry inductor at 3.505 MHz?

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

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	355 W
B	252 W
C	1.42 mW
D	704 W

25. - E6A03

Why does a PN-junction diode not conduct current when reverse biased?

Select	Answer
A	Only N-type semiconductor material can conduct current
B	Only P-type semiconductor material can conduct current
C	Excess holes in P-type material combine with the electrons in N-type material, converting the entire diode into an insulator
D	Holes in P-type material and electrons in the N-type material are separated by the applied voltage, widening the depletion region

26. - E6B07

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

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

27. - E6C08

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

Select	Answer
A	2
B	1
C	3
D	4

28. - E6D08

What is one reason for using powdered-iron cores rather than ferrite cores in an inductor?

Select	Answer
A	Powdered-iron cores use smaller diameter wire for the same inductance
B	Powdered-iron cores generally require fewer turns to produce a given inductance
C	Powdered-iron cores generally maintain their characteristics at higher currents
D	Powdered-iron cores generally have greater initial permeability

29. - E6E11

What is a characteristic of DIP packaging used for integrated circuits?

Select	Answer
A	Low leakage doubly insulated package
B	Package mounts in a direct inverted position
C	A total of two rows of connecting pins placed on opposite sides of the package (Dual In-line Package)
D	Two chips in each package (Dual In Package)

30. - E6F02

What happens to the conductivity of a photoconductive material when light shines on it?

Select	Answer
A	It increases
B	It becomes unstable
C	It stays the same
D	It decreases

31. - E7A01

Which circuit is bistable?

Select	Answer
A	A bipolar amplifier
B	A flip-flop
C	An AND gate
D	An OR gate

32. - E7B10

In Figure E7-1, what is the purpose of R1 and R2?

Select	Answer
A	Feedback
B	Load resistors
C	Voltage divider bias
D	Self bias

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

34. - E7D06

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

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

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. - E7F14

Which of the following would allow a digital signal processing filter to create a sharper filter response?

Select	Answer
A	Higher data rate
B	Double-precision math routines
C	More taps
D	Complex phasor representations

37. - E7G06

What is the gain-bandwidth of an operational amplifier?

Select	Answer
A	The maximum frequency for a filter circuit using that type of amplifier
B	The frequency at which the amplifier's offset voltage is zero
C	The frequency at which the open-loop gain of the amplifier equals one
D	The gain of the amplifier at a filter's cutoff frequency

38. - E7H04

How is positive feedback supplied in a Colpitts oscillator?

Select	Answer
A	Through link coupling
B	Through a neutralizing capacitor
C	Through a tapped coil
D	Through a capacitive divider

39. - E8A03

What type of wave does a Fourier analysis show to be made up of sine waves of a given fundamental frequency plus all its harmonics?

Select	Answer
A	A cosine wave
B	A sawtooth wave
C	A sine wave
D	A square wave

40. - E8B05

What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus-or-minus 5 kHz when the maximum modulation frequency is 3 kHz?

Select	Answer
A	0.6
B	1.67
C	60
D	0.167

41. - E8C01

How is Forward Error Correction implemented?

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

42. - E8D03

How does the spread spectrum technique of frequency hopping work?

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

43. - E9A13

What term describes station output, taking into account all gains and losses?

Select	Answer
A	Power factor
B	Effective radiated power
C	Half-power bandwidth
D	Apparent power

44. - E9B05

What type of antenna pattern is shown in Figure E9-2?

Select	Answer
A	Radiation resistance
B	Elevation
C	Azimuth
D	Polarization

45. - E9C02

What is the radiation pattern of two 1/4-wavelength vertical antennas spaced 1/4 wavelength apart and fed 90 degrees out of phase?

Select	Answer
A	A figure-8 broadside to the axis of the array
B	A figure-8 end-fire along the axis of the array
C	Cardioid
D	Omni-directional

46. - E9D08

What happens as the Q of an antenna increases?

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

47. - E9E09

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

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

48. - E9F05

What is the approximate physical length of a solid polyethylene dielectric coaxial transmission line that is electrically 1/4 wavelength long at 14.1 MHz?

Select	Answer
A	5.3 meters
B	4.3 meters
C	10.6 meters
D	3.5 meters

49. - E9G02

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

Select	Answer
A	Resistance circles and reactance arcs
B	Voltage lines and current chords
C	Resistance lines and reactance chords
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 modifies the pattern of a DF antenna array to provide a null in one direction
C	It provides diversity reception that cancels multipath signals
D	It increases the sensitivity of a DF antenna array

Figure E5-1

Figure E6-3

Figure E7-1

Figure E7-2

Figure E9-2