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

Logging in (or registering) will help the system to select questions that you need to focus on.

1. - E0A11

Which of the following injuries can result from using high-power UHF or microwave transmitters?

Select	Answer
A	Blood clotting from the intense magnetic field
B	Hearing loss caused by high voltage corona discharge
C	Localized heating of the body from RF exposure in excess of the MPE limits
D	Ingestion of ozone gas from the cooling system

2. - E1A01

Which of the following carrier frequencies is illegal for LSB AFSK emissions on the 17 meter band RTTY and data segment of 18.068 to 18.110 MHz?

Select	Answer
A	18.107 MHz
B	18.100 MHz
C	18.110 MHz
D	18.068 MHz

3. - E1B09

Which amateur stations may be operated under RACES rules?

Select	Answer
A	Any FCC-licensed amateur station certified by the responsible civil defense organization for the area served
B	Any FCC-licensed amateur station except a Technician Class
C	Only those club stations licensed to Amateur Extra Class operators
D	Any FCC-licensed amateur station participating in the Military Auxiliary Radio System (MARS)

4. - E1C05

When may an automatically controlled station originate third party communications?

Select	Answer
A	When approved by the National Telecommunication and Information Administration
B	When agreed upon by the sending or receiving station
C	Never
D	Only when transmitting RTTY or data emissions

5. - E1D12

Which of the following amateur stations may transmit one-way communications?

Select	Answer
A	A message forwarding station or automatically controlled digital station
B	A local repeater or linked repeater station
C	All these choices are correct
D	A space station, beacon station, or telecommand station

6. - E1E10

What must the administering VEs do after the administration of a successful examination for an amateur operator license?

Select	Answer
A	They must submit the application document to the coordinating VEC according to the coordinating VEC instructions
B	They must collect and send the documents to the FCC according to instructions
C	They must collect and send the documents to the NCVEC for grading
D	They must collect and submit the documents to the coordinating VEC for grading

7. - E1F03

Under what circumstances may a dealer sell an external RF power amplifier capable of operation below 144 MHz if it has not been granted FCC certification?

Select	Answer
A	The equipment dealer assembled it from a kit
B	It was imported from a manufacturer in another country and was certificated by that country's government
C	It was purchased in used condition from an amateur operator and is sold to another amateur operator for use at that operator's station
D	It was imported from a manufacturer in a country that does not require certification of RF power amplifiers

8. - E2A06

What are Keplerian elements?

Select	Answer
A	High-emission heater filaments used in magnetron tubes
B	Parameters that define the orbit of a satellite
C	Encrypting codes used for spread spectrum modulation
D	Phase reversing elements in a Yagi antenna

9. - E2B02

How many horizontal lines make up a fast-scan (NTSC) television frame?

Select	Answer
A	30
B	60
C	1080
D	525

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 ARRL Section of the remote station
C	/ followed by the USPS two-letter abbreviation for the state in which the remote station is located
D	No additional indicator is required

11. - E2D04

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

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

12. - E2E04

What is indicated when one of the ellipses in an FSK crossed-ellipse display suddenly disappears?

Select	Answer
A	The receiver has drifted 5 kHz from the desired receive frequency
B	The mark and space signal have been inverted
C	Selective fading has occurred
D	One of the signal filters is saturated

13. - E3A05

Tropospheric propagation of microwave signals often occurs in association with what phenomenon?

Select	Answer
A	Warm and cold fronts
B	Sprites and jets
C	Lightning discharges
D	Grayline

14. - E3B11

At what time of day can sporadic E propagation occur?

Select	Answer
A	Any time
B	Only around sunset
C	Only around sunset and sunrise
D	Only in hours of darkness

15. - E3C14

Why does the radio-path horizon distance exceed the geometric horizon?

Select	Answer
A	D-region skip
B	E-region skip
C	Due to the Doppler effect
D	Downward bending due to density variations in the atmosphere

16. - E4A07

Which of the following is an advantage of using an antenna analyzer compared to an SWR bridge to measure antenna SWR?

Select	Answer
A	Antenna analyzers do not need an external RF source
B	All these choices are correct
C	Antenna analyzers display a time-varying representation of the modulation envelope
D	Antenna analyzers automatically tune your antenna for resonance

17. - E4B11

Which of the following can be measured with a vector network analyzer?

Select	Answer
A	Output impedance
B	Reflection coefficient
C	Input impedance
D	All these choices are correct

18. - E4C09

Which of the following choices is a good reason for selecting a high frequency for the design of the IF in a superheterodyne HF or VHF communications receiver?

Select	Answer
A	Improved receiver noise figure
B	Reduced drift
C	Fewer components in the receiver
D	Easier for front-end circuitry to eliminate image responses

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

20. - E4E02

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

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

21. - E5A08

What is the phase relationship between the current through and the voltage across a series resonant circuit at resonance?

Select	Answer
A	The voltage and current are 180 degrees out of phase
B	The voltage leads the current by 90 degrees
C	The current leads the voltage by 90 degrees
D	The voltage and current are in phase

22. - E5B01

What is the term for the time required for the capacitor in an RC circuit to be charged to 63.2% of the applied voltage or to discharge to 36.8% of its initial voltage?

Select	Answer
A	One time constant
B	An exponential rate of one
C	One exponential period
D	A time factor of one

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 7
C	Point 1
D	Point 8

24. - E5D03

What is microstrip?

Select	Answer
A	Lightweight transmission line made of common zip cord
B	Precision printed circuit conductors above a ground plane that provide constant impedance interconnects at microwave frequencies
C	Miniature coax used for low power applications
D	Short lengths of coax mounted on printed circuit boards to minimize time delay between microwave circuits

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

26. - E6B10

In Figure E6-2, what is the schematic symbol for a light-emitting diode?

Select	Answer
A	6
B	1
C	7
D	5

27. - E6C11

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

Select	Answer
A	2
B	5
C	6
D	4

28. - E6D05

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

Select	Answer
A	Ferrite toroids generally require fewer turns to produce a given inductance value
B	Ferrite toroids generally have lower initial permeability
C	Ferrite toroids are easier to use with surface mount technology
D	Ferrite toroids generally have better temperature stability

29. - E6E03

Which of the following materials is likely to provide the highest frequency of operation when used in MMICs?

Select	Answer
A	Silicon nitride
B	Silicon dioxide
C	Silicon
D	Gallium nitride

30. - E6F05

Which describes an optical shaft encoder?

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

31. - E7A08

What logical operation does an OR gate perform?

Select	Answer
A	It only produces logic 0 at its output when all inputs are logic 1
B	It produces logic 1 at its output if all inputs are logic 0
C	It produces logic 1 at its output if any or all inputs are logic 1
D	It produces logic 0 at its output if all inputs are logic 1

32. - E7B02

What is a Class D amplifier?

Select	Answer
A	A frequency doubling amplifier
B	A low power amplifier that uses a differential amplifier for improved linearity
C	A type of amplifier that uses switching technology to achieve high efficiency
D	An amplifier that uses drift-mode FETs for high efficiency

33. - E7C11

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

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

34. - E7D08

What type of circuit is shown in Figure E7-2?

Select	Answer
A	Linear voltage regulator
B	Grounded emitter amplifier
C	Monostable multivibrator
D	Switching voltage regulator

35. - E7E05

What circuit is added to an FM transmitter to boost the higher audio frequencies?

Select	Answer
A	A heterodyne suppressor
B	A de-emphasis network
C	A heterodyne enhancer
D	A pre-emphasis network

36. - E7F06

What is the minimum number of bits required for an analog-to-digital converter to sample a signal with a range of 1 volt at a resolution of 1 millivolt?

Select	Answer
A	10 bits
B	8 bits
C	6 bits
D	4 bits

37. - E7G12

What is an operational amplifier?

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

38. - E7H09

What type of frequency synthesizer circuit uses a phase accumulator, lookup table, digital to analog converter, and a low-pass anti-alias filter?

Select	Answer
A	A diode-switching matrix synthesizer
B	A direct digital synthesizer
C	A phase-locked loop synthesizer
D	A hybrid synthesizer

39. - E8A09

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

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

40. - E8B01

What is the modulation index of an FM signal?

Select	Answer
A	The type of modulation used by the transmitter
B	The ratio of frequency deviation to modulating signal frequency
C	The bandwidth of the transmitted signal divided by the modulating signal frequency
D	The ratio of modulating signal amplitude to frequency deviation

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 a special algorithm to the receiving station along with the data characters
D	By transmitting extra data that may be used to detect and correct transmission errors

42. - E8D10

What are some of the differences between the Baudot digital code and ASCII?

Select	Answer
A	Baudot uses 6 data bits per character, ASCII uses 7 or 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes
B	Baudot uses 5 data bits per character, ASCII uses 7 or 8; Baudot uses 2 characters as letters/figures shift codes, ASCII has no letters/figures shift code
C	Baudot uses 4 data bits per character, ASCII uses 7 or 8; Baudot uses 1 character as a letters/figures shift code, ASCII has no letters/figures code
D	Baudot uses 7 data bits per character, ASCII uses 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes

43. - E9A08

What is antenna bandwidth?

Select	Answer
A	Antenna length divided by the number of elements
B	The angle formed between two imaginary lines drawn through the element ends
C	The frequency range over which an antenna satisfies a performance requirement
D	The angle between the half-power radiation points

44. - E9B07

How does the total amount of radiation emitted by a directional gain antenna compare with the total amount of radiation emitted from a theoretical isotropic antenna, assuming each is driven by the same amount of power?

Select	Answer
A	The total amount of radiation from the directional antenna is increased by the gain of the antenna
B	The total amount of radiation from the directional antenna is stronger by its front-to-back ratio
C	The radiation from the isotropic antenna is 2.15 dB stronger than that from the directional antenna
D	They are the same

45. - E9C04

What happens to the radiation pattern of an unterminated long wire antenna as the wire length is increased?

Select	Answer
A	The lobes become more perpendicular to the wire
B	The lobes align more in the direction of the wire
C	The vertical angle increases
D	The front-to-back ratio decreases

46. - E9D03

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

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

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	50 ohms
D	62 ohms

48. - E9F13

What impedance does a 1/4-wavelength transmission line present to a generator when the line is shorted at the far end?

Select	Answer
A	The same as the characteristic impedance of the transmission line
B	Very high impedance
C	The same as the generator output impedance
D	Very low impedance

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 current axis
C	The reactance axis
D	The voltage axis

50. - E9H05

What is the main drawback of a small wire-loop antenna for direction finding?

Select	Answer
A	All these choices are correct
B	It has a bidirectional pattern
C	It has no clearly defined null
D	It is practical for use only on VHF and higher bands

Figure E5-1

Figure E6-2

Figure E6-3

Figure E7-2

Figure E9-3