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

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1. - E0A08

What does SAR measure?

Select	Answer
A	Signal Amplification Rating
B	The rate at which RF energy is absorbed by the body
C	The rate of RF energy reflected from stationary terrain
D	Synthetic Aperture Ratio of the human body

2. - E1A12

What special operating frequency restrictions are imposed on slow scan TV transmissions?

Select	Answer
A	They are restricted to phone band segments
B	They are restricted to 7.245 MHz, 14.245 MHz, 21.345 MHz, and 28.945 MHz
C	None; they are allowed on all amateur frequencies
D	They are not permitted above 54 MHz

3. - E1B04

What must be done before placing an amateur station within an officially designated wilderness area or wildlife preserve, or an area listed in the National Register of Historic Places?

Select	Answer
A	A proposal must be submitted to the National Park Service
B	An Environmental Assessment must be submitted to the FCC
C	A form FSD-15 must be submitted to the Department of the Interior
D	A letter of intent must be filed with the Environmental Protection Agency

4. - E1C12

On what portion of the 630 meter band are phone emissions permitted?

Select	Answer
A	None
B	Only the top 3 kHz
C	Only the bottom 3 kHz
D	The entire band

5. - E1D09

Which UHF amateur bands have frequencies authorized for space stations?

Select	Answer
A	70 cm and 13 cm
B	70 cm only
C	33 cm and 13 cm
D	70 cm and 33 cm

6. - E1E04

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

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

7. - E1F07

When may an amateur station send a message to a business?

Select	Answer
A	When the control operator is employed by the FCC or another government agency
B	When transmitting international third-party communications
C	When neither the amateur nor his or her employer has a pecuniary interest in the communications
D	When the total money involved does not exceed $25

8. - E2A02

Which of the following occurs when a satellite is using an inverting linear transponder?

Select	Answer
A	Signal position in the band is reversed
B	Doppler shift is reduced because the uplink and downlink shifts are in opposite directions
C	All these choices are correct
D	Upper sideband on the uplink becomes lower sideband on the downlink, and vice versa

9. - E2B06

What is vestigial sideband modulation?

Select	Answer
A	A type of modulation in which one sideband is inverted
B	Spread spectrum modulation achieved by applying FM modulation following single sideband amplitude modulation
C	Narrow-band FM modulation achieved by filtering one sideband from the audio before frequency modulating the carrier
D	Amplitude modulation in which one complete sideband and a portion of the other are transmitted

10. - E2C03

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

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

11. - E2D11

Which of the following data are used by the APRS network to communicate station location?

Select	Answer
A	Polar coordinates
B	Latitude and longitude
C	Radio direction finding spectrum analysis
D	Time and frequency

12. - E2E11

What is the difference between direct FSK and audio FSK?

Select	Answer
A	Direct FSK can transmit faster baud rates
B	Direct FSK occupies less bandwidth
C	Only direct FSK can be decoded by computer
D	Direct FSK applies the data signal to the transmitter VFO, while AFSK transmits tones via phone

13. - E3A06

What might help to restore contact when DX signals become too weak to copy across an entire HF band a few hours after sunset?

Select	Answer
A	Wait 90 minutes or so for the signal degradation to pass
B	Wait 24 hours before attempting another communication on the band
C	Switch to a higher frequency HF band
D	Switch to a lower frequency HF band

14. - E3B07

What happens to linearly polarized radio waves that split into ordinary and extraordinary waves in the ionosphere?

Select	Answer
A	They become phase locked
B	They become depolarized
C	They become elliptically polarized
D	They are bent toward the magnetic poles

15. - E3C04

What does the value of Bz (B sub Z) represent?

Select	Answer
A	Critical frequency for vertical transmissions
B	Duration of long-delayed echoes
C	Geomagnetic field stability
D	Direction and strength of the interplanetary magnetic field

16. - E4A04

How is the compensation of an oscilloscope probe typically adjusted?

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

17. - E4B03

Which S parameter is equivalent to forward gain?

Select	Answer
A	S22
B	S12
C	S21
D	S11

18. - E4C03

What is the term for the suppression in an FM receiver of one signal by another stronger signal on the same frequency?

Select	Answer
A	Frequency discrimination
B	Capture effect
C	Desensitization
D	Cross-modulation interference

19. - E4D08

What causes intermodulation in an electronic circuit?

Select	Answer
A	Nonlinear circuits or devices
B	Lack of neutralization
C	Too little gain
D	Positive feedback

20. - E4E06

What is one type of electrical interference that might be caused by a nearby personal computer?

Select	Answer
A	A clicking noise at intervals of a few seconds
B	A whining type noise that continually pulses off and on
C	A loud AC hum in the audio output of your station receiver
D	The appearance of unstable modulated or unmodulated signals at specific frequencies

21. - E5A02

What is resonance in an LC or RLC circuit?

Select	Answer
A	The lowest frequency that will pass current
B	The frequency at which the reactive impedance equals the resistive impedance
C	The highest frequency that will pass current
D	The frequency at which the capacitive reactance equals the inductive reactance

22. - E5B05

What happens to the magnitude of a pure reactance when it is converted to a susceptance?

Select	Answer
A	The sign is reversed
B	It is shifted by 90 degrees
C	It becomes the reciprocal
D	It is unchanged

23. - E5C06

What does the impedance 50-j25 represent?

Select	Answer
A	25 ohms resistance in series with 50 ohms capacitive reactance
B	50 ohms resistance in series with 25 ohms inductive reactance
C	50 ohms resistance in series with 25 ohms capacitive reactance
D	25 ohms resistance in series with 50 ohms inductive reactance

24. - E5D08

How many watts are consumed in a circuit having a power factor of 0.6 if the input is 200VAC at 5 amperes?

Select	Answer
A	200 watts
B	1600 watts
C	600 watts
D	1000 watts

25. - E6A06

What is the beta of a bipolar junction transistor?

Select	Answer
A	The change in collector current with respect to base current
B	The frequency at which the current gain is reduced to 0.707
C	The switching speed
D	The breakdown voltage of the base to collector junction

26. - E6B09

What is a common use for point-contact diodes?

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

27. - E6C08

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

Select	Answer
A	3
B	2
C	4
D	1

28. - E6D03

Which of the following is an aspect of the piezoelectric effect?

Select	Answer
A	Mechanical deformation of material by the application of a voltage
B	Increased conductivity in the presence of light
C	Generation of electrical energy in the presence of light
D	Mechanical deformation of material by the application of a magnetic field

29. - E6E06

What characteristics of the MMIC make it a popular choice for VHF through microwave circuits?

Select	Answer
A	Controlled gain, low noise figure, and constant input and output impedance over the specified frequency range
B	Nearly infinite gain, very high input impedance, and very low output impedance
C	The ability to retrieve information from a single signal even in the presence of other strong signals
D	Plate current that is controlled by a control grid

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 for generating RTTY signals by means of a rotating light source
D	A device that detects rotation of a control by interrupting a light source with a patterned wheel

31. - E7A07

What logical operation does a NAND gate perform?

Select	Answer
A	It produces logic 0 at its output only when all inputs are logic 0
B	It produces logic 0 at its output only when all inputs are logic 1
C	It produces logic 1 at its output only when all inputs are logic 1
D	It produces logic 0 at its output if some but not all inputs are logic 1

32. - E7B17

Why are odd-order rather than even-order intermodulation distortion products of concern in linear power amplifiers?

Select	Answer
A	Because they maintain the sidebands, thus causing multiple duplicate signals
B	Because they are relatively far in frequency from the desired signal
C	Because they invert the sidebands causing distortion
D	Because they are relatively close in frequency to the desired signal

33. - E7C07

Which describes a Pi-L-network used for matching a vacuum tube final amplifier to a 50-ohm unbalanced output?

Select	Answer
A	A matching network in which all components are isolated from ground
B	A Pi-network with an additional series inductor on the output
C	A Phase Inverter Load network
D	A network with only three discrete parts

34. - E7D08

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

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

35. - E7E07

What is meant by the term "baseband" in radio communications?

Select	Answer
A	The lowest frequency band that the transmitter or receiver covers
B	The unmodulated bandwidth of the transmitted signal
C	The basic oscillator frequency in an FM transmitter that is multiplied to increase the deviation and carrier frequency
D	The frequency range occupied by a message signal prior to modulation

36. - E7F03

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

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

37. - E7G03

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

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

38. - E7H15

Which of these functions can be performed by a phase-locked loop?

Select	Answer
A	Frequency synthesis, FM demodulation
B	Wide-band AF and RF power amplification
C	Photovoltaic conversion, optical coupling
D	Comparison of two digital input signals, digital pulse counter

39. - E8A05

What of the following instruments would be the most accurate for measuring the RMS voltage of a complex waveform?

Select	Answer
A	A grid dip meter
B	A D'Arsonval meter
C	An absorption wave meter
D	A true-RMS calculating meter

40. - E8B07

Orthogonal Frequency Division Multiplexing is a technique used for which type of amateur communication?

Select	Answer
A	High-speed digital modes
B	OFDM signals are not allowed on amateur bands
C	Extremely low-power contacts
D	EME

41. - E8C02

What is the definition of symbol rate in a digital transmission?

Select	Answer
A	The number of characters carried per second by the station-to-station link
B	The rate at which the waveform changes to convey information
C	The number of control characters in a message packet
D	The duration of each bit in a message sent over the air

42. - E8D11

What is one advantage of using ASCII code for data communications?

Select	Answer
A	It uses one character as a shift code to send numeric and special characters
B	It contains fewer information bits per character than any other code
C	It includes built-in error correction features
D	It is possible to transmit both upper and lower case text

43. - E9A13

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

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

44. - E9B02

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

Select	Answer
A	14 dB
B	24 dB
C	18 dB
D	36 dB

45. - E9C07

What is the approximate feed point impedance at the center of a two-wire folded dipole antenna?

Select	Answer
A	450 ohms
B	50 ohms
C	72 ohms
D	300 ohms

46. - E9D08

What happens as the Q of an antenna increases?

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

47. - E9E08

What is a use for a Wilkinson divider?

Select	Answer
A	It divides the operating frequency of a transmitter signal so it can be used on a lower frequency band
B	It is used to feed low-impedance loads from a high-impedance source
C	It is used to feed high-impedance antennas from a low-impedance source
D	It is used to divide power equally between two 50-ohm loads while maintaining 50-ohm input impedance

48. - E9F02

Which of the following has the biggest effect on the velocity factor of a transmission line?

Select	Answer
A	The center conductor resistivity
B	The termination impedance
C	The line length
D	Dielectric materials used in the line

49. - E9G02

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

Select	Answer
A	Voltage lines and current chords
B	Resistance lines and reactance chords
C	Resistance circles and reactance arcs
D	Voltage circles and current arcs

50. - E9H11

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

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

Figure E6-3

Figure E7-2

Figure E9-1