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

2. - E1A13

Who must be in physical control of the station apparatus of an amateur station aboard any vessel or craft that is documented or registered in the United States?

Select	Answer
A	Any person named in an amateur station license grant or a person holding an unrestricted Radiotelephone Operator Permit
B	Any person holding an FCC issued amateur license or who is authorized for alien reciprocal operation
C	Only a person with an FCC Marine Radio license grant
D	Only a person named in an amateur station license grant

3. - E1B10

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

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

4. - E1C02

Which of the following types of communications may be transmitted to amateur stations in foreign countries?

Select	Answer
A	All these choices are correct
B	Messages intended for users of the maritime satellite service
C	Communications incidental to the purpose of the amateur service and remarks of a personal nature
D	Business-related messages for non-profit organizations

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

6. - E1E08

To which of the following examinees may a VE not administer an examination?

Select	Answer
A	Employees of the VE
B	All these choices are correct
C	Relatives of the VE as listed in the FCC rules
D	Friends of the VE

7. - E1F02

What privileges are authorized in the U.S. to persons holding an amateur service license granted by the government of Canada?

Select	Answer
A	The operating terms and conditions of the Canadian amateur service license, not to exceed U.S. Amateur Extra Class license privileges
B	Full privileges, up to and including those of the Amateur Extra Class license, on the 80, 40, 20, 15, and 10 meter bands
C	None, they must obtain a U.S. license
D	All privileges of the Amateur Extra Class license

8. - E2A08

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

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

9. - E2B10

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

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

10. - E2C10

Why might a DX station state that they are listening on another frequency?

Select	Answer
A	To improve operating efficiency by reducing interference
B	Because the DX station may be transmitting on a frequency that is prohibited to some responding stations
C	To separate the calling stations from the DX station
D	All these choices are correct

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	Permits fast-scan TV transmissions over narrow bandwidth
D	Uses only a 65 Hz bandwidth

12. - E2E06

What is the most common data rate used for HF packet?

Select	Answer
A	48 baud
B	110 baud
C	1200 baud
D	300 baud

13. - E3A08

When a meteor strikes the Earth's atmosphere, a cylindrical region of free electrons is formed at what layer of the ionosphere?

Select	Answer
A	The D layer
B	The E layer
C	The F1 layer
D	The F2 layer

14. - E3B06

Which of the following amateur bands most frequently provides long-path propagation?

Select	Answer
A	80 meters
B	10 meters
C	6 meters
D	20 meters

15. - E3C10

What does the 304A solar parameter measure?

Select	Answer
A	The solar wind velocity at 304 degrees from the solar equator, correlated to solar activity
B	The solar emission at 304 GHz, correlated to x-ray flare levels
C	UV emissions at 304 angstroms, correlated to the solar flux index
D	The ratio of x-ray flux to radio flux, correlated to sunspot number

16. - E4A10

Which of the following displays multiple digital signal states simultaneously?

Select	Answer
A	Logic analyzer
B	Network analyzer
C	Bit error rate tester
D	Modulation monitor

17. - E4B06

How much power is being absorbed by the load when a directional power meter connected between a transmitter and a terminating load reads 100 watts forward power and 25 watts reflected power?

Select	Answer
A	100 watts
B	25 watts
C	75 watts
D	125 watts

18. - E4C10

What is an advantage of having a variety of receiver IF bandwidths from which to select?

Select	Answer
A	Multiple frequencies can be received simultaneously if desired
B	The noise figure of the RF amplifier can be adjusted to match the modulation type, thus increasing receiver sensitivity
C	Receive bandwidth can be set to match the modulation bandwidth, maximizing signal-to-noise ratio and minimizing interference
D	Receiver power consumption can be reduced when wider bandwidth is not required

19. - E4D01

What is meant by the blocking dynamic range of a receiver?

Select	Answer
A	The difference in dB between the noise floor and the third-order intercept point
B	The difference in dB between the noise floor and the level of an incoming signal that will cause 1 dB of gain compression
C	The minimum difference in dB between two signals which produce third-order intermodulation products greater than the noise floor
D	The minimum difference in dB between the levels of two FM signals that will cause one signal to block the other

20. - E4E02

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

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

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	Resistance divided by the reactance of either the inductance or capacitance
C	Reactance of the inductance multiplied by the reactance of the capacitance
D	Reactance of either the inductance or capacitance divided by the resistance

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

23. - E5C08

What coordinate system is often used to display the phase angle of a circuit containing resistance, inductive and/or capacitive reactance?

Select	Answer
A	Elliptical coordinates
B	Polar coordinates
C	Maidenhead grid
D	Faraday grid

24. - E5D10

How can the true power be determined in an AC circuit where the voltage and current are out of phase?

Select	Answer
A	By multiplying the apparent power by the power factor
B	By dividing the reactive power by the power factor
C	By multiplying the reactive power by the power factor
D	By dividing the apparent power by the power factor

25. - E6A04

What is the name given to an impurity atom that adds holes to a semiconductor crystal structure?

Select	Answer
A	Insulator impurity
B	N-type impurity
C	Donor impurity
D	Acceptor impurity

26. - E6B09

What is a common use for point-contact diodes?

Select	Answer
A	As a constant voltage source
B	As a high-voltage rectifier
C	As an RF detector
D	As a constant current source

27. - E6C02

What happens when the level of a comparator's input signal crosses the threshold?

Select	Answer
A	The comparator enters latch-up
B	The comparator changes its output state
C	The IC input can be damaged
D	The feedback loop becomes unstable

28. - E6D05

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

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

29. - E6E08

How is power supplied to the most common type of MMIC?

Select	Answer
A	MMICs require no operating bias
B	Through a capacitor and RF choke connected to the amplifier input lead
C	Directly to the bias voltage (VCC IN) lead
D	Through a resistor and/or RF choke connected to the amplifier output lead

30. - E6F07

What is a solid-state relay?

Select	Answer
A	A semiconductor passive delay line
B	A relay using transistors to drive the relay coil
C	A device that uses semiconductors to implement the functions of an electromechanical relay
D	A mechanical relay that latches in the on or off state each time it is pulsed

31. - E7A02

What is the function of a decade counter?

Select	Answer
A	It decodes a binary number for display on a seven-segment LED display
B	It produces one output pulse for every 10 input pulses
C	It decodes a decimal number for display on a seven-segment LED display
D	It produces 10 output pulses for every input pulse

32. - E7B14

Why are switching amplifiers more efficient than linear amplifiers?

Select	Answer
A	The power transistor is at saturation or cutoff most of the time
B	Linear amplifiers have high gain resulting in higher harmonic content
C	Switching amplifiers operate at higher voltages
D	Switching amplifiers use push-pull circuits

33. - E7C05

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

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

34. - E7D15

What is the purpose of a step-start circuit in a high-voltage power supply?

Select	Answer
A	To compensate for variations of the incoming line voltage
B	To allow the filter capacitors to charge gradually
C	To provide a dual-voltage output for reduced power applications
D	To allow for remote control of the power supply

35. - E7E05

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

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

36. - E7F12

Which of the following is an advantage of a Finite Impulse Response (FIR) filter vs an Infinite Impulse Response (IIR) digital filter?

Select	Answer
A	FIR filters can delay all frequency components of the signal by the same amount
B	FIR filters can respond faster to impulses
C	FIR filters are easier to implement for a given set of passband rolloff requirements
D	All these choices are correct

37. - E7G01

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

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

38. - E7H08

Which of the following components can be used to reduce thermal drift in crystal oscillators?

Select	Answer
A	NP0 capacitors
B	Wirewound resistors
C	Non-inductive resistors
D	Toroidal inductors

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	Numerical analysis
C	Vector analysis
D	Differential analysis

40. - E8B01

What is the modulation index of an FM signal?

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

41. - E8C08

How does ARQ accomplish error correction?

Select	Answer
A	If errors are detected, a retransmission is requested
B	Special binary codes provide automatic correction
C	If errors are detected, redundant data is substituted
D	Special polynomial codes provide automatic correction

42. - E8D04

What is the primary effect of extremely short rise or fall time on a CW signal?

Select	Answer
A	The generation of RF harmonics
B	Limits data speed
C	The generation of key clicks
D	More difficult to copy

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. - E9B03

In the antenna radiation pattern shown in Figure E9-1, what is the front-to-side ratio?

Select	Answer
A	14 dB
B	12 dB
C	24 dB
D	18 dB

45. - E9C05

Which of the following is a type of OCFD antenna?

Select	Answer
A	A remotely tunable dipole antenna using orthogonally controlled frequency diversity
B	A multiband dipole antenna using one-way circular polarization for frequency diversity
C	A dipole fed approximately 1/3 the way from one end with a 4:1 balun to provide multiband operation
D	A folded dipole center-fed with 300-ohm transmission line

46. - E9D04

Why should an HF mobile antenna loading coil have a high ratio of reactance to resistance?

Select	Answer
A	To lower the radiation angle
B	To minimize the Q
C	To swamp out harmonics
D	To minimize losses

47. - E9E03

What is the name of the matching system that uses a section of transmission line connected in parallel with the feed line at or near the feed point?

Select	Answer
A	The delta match
B	The stub match
C	The gamma match
D	The omega match

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	The same as the generator output impedance
C	Very low impedance
D	Very high impedance

49. - E9G10

What do the arcs on a Smith chart represent?

Select	Answer
A	Points with constant reactance
B	SWR
C	Points with constant resistance
D	Frequency

50. - E9H05

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

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

Figure E9-1