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

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1. - E0A09

Which insulating material commonly used as a thermal conductor for some types of electronic devices is extremely toxic if broken or crushed and the particles are accidentally inhaled?

Select	Answer
A	Uranium Hexafluoride
B	Mica
C	Beryllium Oxide
D	Zinc oxide

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

3. - E1B10

What frequencies are authorized to an amateur station operating under RACES rules?

Select	Answer
A	Specific segments in the amateur service MF, HF, VHF and UHF bands
B	Specific local government channels
C	All amateur service frequencies authorized to the control operator
D	Military Auxiliary Radio System (MARS) channels

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

5. - E1D08

Which VHF amateur bands have frequencies authorized for space stations?

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

6. - E1E04

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

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

7. - E1F04

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

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

8. - E2A01

What is the direction of an ascending pass for an amateur satellite?

Select	Answer
A	From north to south
B	From south to north
C	From east to west
D	From west to east

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 carries the audio information
C	The vestigial sideband contains chroma information
D	Vestigial sideband provides high frequency emphasis to sharpen the picture

10. - E2C03

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

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

11. - E2D07

What digital protocol is used by APRS?

Select	Answer
A	PACTOR
B	802.11
C	AX.25
D	AMTOR

12. - E2E10

Which of these digital modes has the narrowest bandwidth?

Select	Answer
A	300-baud packet
B	MFSK16
C	PSK31
D	170 Hz shift, 45-baud RTTY

13. - E3A10

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

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

14. - E3B10

Why is chordal hop propagation desirable?

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

15. - E3C15

What might be indicated by a sudden rise in radio background noise across a large portion of the HF spectrum?

Select	Answer
A	Increased transequatorial propagation is likely
B	A temperature inversion has occurred
C	A solar flare has occurred
D	Long-path propagation is likely

16. - E4A05

What is the purpose of the prescaler function on a frequency counter?

Select	Answer
A	It divides a higher frequency signal so a low-frequency counter can display the input frequency
B	It amplifies low-level signals for more accurate counting
C	It multiplies a higher frequency signal so a low-frequency counter can display the operating frequency
D	It prevents oscillation in a low-frequency counter circuit

17. - E4B08

Which of the following can be used to measure the Q of a series-tuned circuit?

Select	Answer
A	The bandwidth of the circuit's frequency response
B	The resonant frequency of the circuit
C	The frequency shift
D	The inductance to capacitance ratio

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 dynamic range by attenuating strong signals near the receive frequency
D	It improves intelligibility by using low Q circuitry to reduce ringing

19. - E4D11

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

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

20. - E4E02

Which of the following types of noise can often be reduced with a digital signal processing noise filter?

Select	Answer
A	Broadband white noise
B	Power line noise
C	Ignition noise
D	All these choices are correct

21. - E5A03

What is the magnitude of the impedance of a series RLC circuit at resonance?

Select	Answer
A	High, as compared to the circuit resistance
B	Approximately equal to circuit resistance
C	Approximately equal to inductive reactance
D	Approximately equal to capacitive reactance

22. - E5B12

What is admittance?

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

23. - E5C01

Which of the following represents capacitive reactance in rectangular notation?

Select	Answer
A	-jX
B	Delta
C	+jX
D	Omega

24. - E5D12

How many watts are consumed in a circuit having a power factor of 0.2 if the input is 100 VAC at 4 amperes?

Select	Answer
A	50 watts
B	80 watts
C	400 watts
D	2000 watts

25. - E6A01

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

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

26. - E6B08

Which of the following is a Schottky barrier diode?

Select	Answer
A	Electrolytic rectifier
B	Thermionic emission diode
C	Metal-semiconductor junction
D	PIN junction

27. - E6C10

In Figure E6-3, what is the schematic symbol for a NOR gate?

Select	Answer
A	2
B	3
C	4
D	1

28. - E6D09

What devices are commonly used as VHF and UHF parasitic suppressors at the input and output terminals of a transistor HF amplifier?

Select	Answer
A	Butterworth filters
B	Ferrite beads
C	Steel-core toroids
D	Electrolytic capacitors

29. - E6E05

Which of the following noise figure values is typical of a low-noise UHF preamplifier?

Select	Answer
A	-20 dBm
B	2 dB
C	-10 dB
D	44 dBm

30. - E6F02

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

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

31. - E7A09

What logical operation is performed by an exclusive NOR gate?

Select	Answer
A	It produces logic 0 at its output only if all inputs are logic 0
B	It produces logic 0 at its output if only one input is logic 1
C	It produces logic 1 at its output only if all inputs are logic 1
D	It produces logic 1 at its output if only one input is logic 1

32. - E7B18

What is a characteristic of a grounded-grid amplifier?

Select	Answer
A	High power gain
B	Low input impedance
C	High filament voltage
D	Low bandwidth

33. - E7C05

Which filter type is described as having ripple in the passband and a sharp cutoff?

Select	Answer
A	A Chebyshev filter
B	A Butterworth filter
C	An active LC filter
D	A passive op-amp filter

34. - E7D06

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

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

35. - E7E06

Why is de-emphasis commonly used in FM communications receivers?

Select	Answer
A	To reduce impulse noise reception
B	To remove third-order distortion products
C	For higher efficiency
D	For compatibility with transmitters using phase modulation

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	Provide incremental signal delays for filter algorithms
D	Select the point at which baseband signals are generated

37. - E7G12

What is an operational amplifier?

Select	Answer
A	A RF amplifier used in the UHF and microwave regions
B	An amplifier used to increase the average output of frequency modulated amateur signals to the legal limit
C	A high-gain, direct-coupled differential amplifier with very high input impedance and very low output impedance
D	A digital audio amplifier whose characteristics are determined by components external to the amplifier

38. - E7H04

How is positive feedback supplied in a Colpitts oscillator?

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

39. - E8A06

What is the approximate ratio of PEP-to-average power in a typical single-sideband phone signal?

Select	Answer
A	100 to 1
B	25 to 1
C	2.5 to 1
D	1 to 1

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	0.167
B	0.6
C	60
D	1.67

41. - E8C09

Which digital code allows only one bit to change between sequential code values?

Select	Answer
A	Binary Coded Decimal Code
B	Extended Binary Coded Decimal Interchange Code
C	Excess 3 code
D	Gray code

42. - E8D07

What is a common cause of overmodulation of AFSK signals?

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

43. - E9A12

How much gain does an antenna have compared to a 1/2-wavelength dipole when it has 6 dB gain over an isotropic antenna?

Select	Answer
A	8.15 dB
B	6.0 dB
C	2.79 dB
D	3.85 dB

44. - E9B06

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

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

45. - E9C11

How is the far-field elevation pattern of a vertically polarized antenna affected by being mounted over seawater versus soil?

Select	Answer
A	Fewer vertical angle lobes will be present
B	The low-angle radiation decreases
C	The low-angle radiation increases
D	Additional higher vertical angle lobes will appear

46. - E9D08

What happens as the Q of an antenna increases?

Select	Answer
A	SWR bandwidth decreases
B	Gain is reduced
C	SWR bandwidth increases
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	62 ohms
B	75 ohms
C	50 ohms
D	450 ohms

48. - E9F08

Which of the following is a significant difference between foam dielectric coaxial cable and solid dielectric cable, assuming all other parameters are the same?

Select	Answer
A	Foam dielectric has higher velocity factor
B	Foam dielectric has lower loss per unit of length
C	Foam dielectric has lower safe operating voltage limits
D	All these choices are correct

49. - E9G09

What third family of circles is often added to a Smith chart during the process of solving problems?

Select	Answer
A	Antenna-length circles
B	Coaxial-length circles
C	Standing wave ratio circles
D	Radiation-pattern circles

50. - E9H11

What feature of a cardioid pattern antenna makes it useful for direction finding?

Select	Answer
A	A very sharp peak
B	Broadband response
C	A very sharp single null
D	High radiation angle

Figure E6-3

Figure E7-2

Figure E9-2