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

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1. - E0A07

How may dangerous levels of carbon monoxide from an emergency generator be detected?

Select	Answer
A	By the odor
B	Any ordinary smoke detector can be used
C	By the yellowish appearance of the gas
D	Only with a carbon monoxide detector

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 operator must have an FCC Marine or Aircraft endorsement on his or her amateur license
B	The amateur station must have a power supply that is completely independent of the main ship or aircraft power supply
C	The amateur station operator must agree not to transmit when the main radio of the ship or aircraft is in use
D	Its operation must be approved by the master of the ship or the pilot in command of the aircraft

3. - E1B10

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

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

4. - E1C14

How long must an operator wait after filing a notification with the Utilities Technology Council (UTC) before operating on the 2200 meter or 630 meter band?

Select	Answer
A	Operators may operate after 30 days, providing they have not been told that their station is within 1 km of PLC systems using those frequencies
B	Operators must not operate until approval is received
C	Operations may commence immediately, and may continue unless interference is reported by the UTC
D	Operators may not operate until a test signal has been transmitted in coordination with the local power company

5. - E1D04

Which of the following is required in the identification transmissions from a balloon-borne telemetry station?

Select	Answer
A	The station's six-character Maidenhead grid locator
B	Call sign
C	All these choices are correct
D	The output power of the balloon transmitter

6. - E1E12

What must the VE team do with the application form if the examinee does not pass the exam?

Select	Answer
A	Destroy the application form
B	Return the application document to the examinee
C	Maintain the application form with the VEC's records
D	Send the application form to the FCC and inform the FCC of the grade

7. - E1F01

On what frequencies are spread spectrum transmissions permitted?

Select	Answer
A	Only on amateur frequencies above 222 MHz
B	Only on amateur frequencies above 144 MHz
C	Only on amateur frequencies above 50 MHz
D	Only on amateur frequencies above 420 MHz

8. - E2A12

What is the purpose of digital store-and-forward functions on an amateur radio satellite?

Select	Answer
A	To store digital messages in the satellite for later download by other stations
B	To delay download of telemetry between satellites
C	To upload operational software for the transponder
D	To relay messages between satellites

9. - E2B03

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

Select	Answer
A	By scanning two fields simultaneously
B	By scanning lines from left to right in one field and right to left in the next
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. - 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	/R# where # is the district of the remote station
B	/ followed by the USPS two-letter abbreviation for the state in which the remote station is located
C	No additional indicator is required
D	/ followed by the ARRL Section of the remote station

11. - E2D05

What is one advantage of the JT65 mode?

Select	Answer
A	Easily copied by ear if necessary
B	The ability to decode signals which have a very low signal-to-noise ratio
C	Uses only a 65 Hz bandwidth
D	Permits fast-scan TV transmissions over narrow bandwidth

12. - E2E08

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

Select	Answer
A	AMTOR
B	PACTOR
C	RTTY
D	Hellschreiber

13. - E3A07

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

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

14. - E3B10

Why is chordal hop propagation desirable?

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

15. - E3C07

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

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

16. - E4A04

How is the compensation of an oscilloscope probe typically adjusted?

Select	Answer
A	A frequency standard is displayed and the probe is adjusted until the deflection time is accurate
B	A DC voltage standard is displayed and the probe is adjusted until the displayed voltage is accurate
C	A high frequency sine wave is displayed and the probe is adjusted for maximum amplitude
D	A square wave is displayed and the probe is adjusted until the horizontal portions of the displayed wave are as nearly flat as possible

17. - E4B03

Which S parameter is equivalent to forward gain?

Select	Answer
A	S22
B	S11
C	S21
D	S12

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 galactic noise contribution to minimum detectable signal
C	The theoretical noise in a 1 Hz bandwidth at the input of a perfect receiver at room temperature
D	The noise figure of a 1 Hz bandwidth receiver

19. - E4D04

Which of the following may reduce or eliminate intermodulation interference in a repeater caused by another transmitter operating in close proximity?

Select	Answer
A	A properly terminated circulator at the output of the repeater's transmitter
B	A band-pass filter in the feed line between the transmitter and receiver
C	Utilizing a Class D final amplifier
D	Utilizing a Class C final amplifier

20. - E4E07

Which of the following can cause shielded cables to radiate or receive interference?

Select	Answer
A	Use of braided shielding material
B	Common-mode currents on the shield and conductors
C	Low inductance ground connections at both ends of the shield
D	Tying all ground connections to a common point resulting in differential-mode currents in the shield

21. - E5A06

What is the magnitude of the circulating current within the components of a parallel LC circuit at resonance?

Select	Answer
A	It is at a minimum
B	It equals 2 multiplied by pi, multiplied by frequency, multiplied by inductance
C	It equals 1 divided by the quantity 2 times pi, multiplied by the square root of inductance L multiplied by capacitance C
D	It is at a maximum

22. - E5B07

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 500 ohms, R is 1 kilohm, and XL is 250 ohms?

Select	Answer
A	14.0 degrees with the voltage lagging the current
B	68.2 degrees with the voltage lagging the current
C	14.0 degrees with the voltage leading the current
D	68.2 degrees with the voltage leading the current

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 8
B	Point 7
C	Point 1
D	Point 3

24. - E5D02

Why is it important to keep lead lengths short for components used in circuits for VHF and above?

Select	Answer
A	To maintain component lifetime
B	All these choices are correct
C	To avoid unwanted inductive reactance
D	To increase the thermal time constant

25. - E6A09

What is a depletion-mode FET?

Select	Answer
A	An FET that has no current flow between source and drain when no gate voltage is applied
B	Any FET without a channel
C	Any FET for which holes are the majority carriers
D	An FET that exhibits a current flow between source and drain when no gate voltage is applied

26. - E6B02

What is an important characteristic of a Schottky diode as compared to an ordinary silicon diode when used as a power supply rectifier?

Select	Answer
A	More constant reverse avalanche voltage
B	Much higher reverse voltage breakdown
C	Longer carrier retention time
D	Less forward voltage drop

27. - E6C11

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

Select	Answer
A	4
B	2
C	6
D	5

28. - E6D10

What is a primary advantage of using a toroidal core instead of a solenoidal core in an inductor?

Select	Answer
A	Toroidal cores confine most of the magnetic field within the core material
B	Toroidal cores make it easier to couple the magnetic energy into other components
C	Toroidal cores exhibit greater hysteresis
D	Toroidal cores have lower Q characteristics

29. - E6E04

Which is the most common input and output impedance of circuits that use MMICs?

Select	Answer
A	50 ohms
B	450 ohms
C	10 ohms
D	300 ohms

30. - E6F05

Which describes an optical shaft encoder?

Select	Answer
A	A device that measures the strength of a beam of light using analog to digital conversion
B	A digital encryption device often used to encrypt spacecraft control signals
C	A device that detects rotation of a control by interrupting a light source with a patterned wheel
D	A device for generating RTTY signals by means of a rotating light source

31. - E7A04

How many flip-flops are required to divide a signal frequency by 4?

Select	Answer
A	1
B	8
C	2
D	4

32. - E7B10

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

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

33. - E7C11

Which of the following describes a receiving filter's ability to reject signals occupying an adjacent channel?

Select	Answer
A	Phase response
B	Passband ripple
C	Shape factor
D	Noise factor

34. - E7D02

What is a characteristic of a switching electronic voltage regulator?

Select	Answer
A	The resistance of a control element is varied in direct proportion to the line voltage or load current
B	It gives a ramp voltage at its output
C	It is generally less efficient than a linear regulator
D	The controlled device's duty cycle is changed to produce a constant average output voltage

35. - E7E09

What occurs when an excessive amount of signal energy reaches a mixer circuit?

Select	Answer
A	A beat frequency is generated
B	Mixer blanking occurs
C	Automatic limiting occurs
D	Spurious mixer products are generated

36. - E7F03

What type of digital signal processing filter is used to generate an SSB signal?

Select	Answer
A	A notch filter
B	An elliptical filter
C	A Hilbert-transform filter
D	An adaptive filter

37. - E7G03

What is the typical input impedance of an op-amp?

Select	Answer
A	Very high
B	Very low
C	100 ohms
D	1000 ohms

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

39. - E8A01

What is the name of the process that shows that a square wave is made up of a sine wave plus all its odd harmonics?

Select	Answer
A	Fourier analysis
B	Differential analysis
C	Numerical analysis
D	Vector analysis

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. - E8C11

What is the relationship between symbol rate and baud?

Select	Answer
A	They are the same
B	Baud is only used for RTTY
C	Baud is twice the symbol rate
D	Symbol rate is only used for packet-based modes

42. - E8D02

What spread spectrum communications technique uses a high-speed binary bit stream to shift the phase of an RF carrier?

Select	Answer
A	Binary phase-shift keying
B	Direct sequence
C	Phase compandored spread spectrum
D	Frequency hopping

43. - E9A06

What is the effective radiated power relative to a dipole of a repeater station with 200 watts transmitter power output, 4 dB feed line loss, 3.2 dB duplexer loss, 0.8 dB circulator loss, and 10 dBd antenna gain?

Select	Answer
A	317 watts
B	300 watts
C	126 watts
D	2000 watts

44. - E9B01

In the antenna radiation pattern shown in Figure E9-1, what is the beamwidth?

Select	Answer
A	50 degrees
B	75 degrees
C	25 degrees
D	30 degrees

45. - E9C09

Which of the following describes a G5RV antenna?

Select	Answer
A	A multi-band dipole antenna fed with coax and a balun through a selected length of open wire transmission line
B	A wide band dipole using shorted coaxial cable for the radiating elements and fed with a�4:1 balun
C	A multi-band trap antenna
D	A phased array antenna consisting of multiple loops

46. - E9D03

Where should a high Q loading coil be placed to minimize losses in a shortened vertical antenna?

Select	Answer
A	As low as possible on the vertical radiator
B	Near the center of the vertical radiator
C	As close to the transmitter as possible
D	At a voltage node

47. - E9E04

What is the purpose of the series capacitor in a gamma-type antenna matching network?

Select	Answer
A	To cancel the inductive reactance of the matching network
B	To provide a rejection notch that prevents the radiation of harmonics
C	To provide DC isolation between the feed line and the antenna
D	To transform the antenna impedance to a higher value

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	10.6 meters
B	5.3 meters
C	4.3 meters
D	3.5 meters

49. - E9G08

What is the process of normalization with regard to a Smith chart?

Select	Answer
A	Reassigning impedance values with regard to the prime center
B	Reassigning resistance values with regard to the reactance axis
C	Reassigning reactance values with regard to the resistance axis
D	Reassigning prime center with regard to the reactance axis

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 E5-1

Figure E6-3

Figure E7-1

Figure E9-1