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	Beryllium Oxide
B	Zinc oxide
C	Mica
D	Uranium Hexafluoride

2. - E1A08

If a station in a message forwarding system inadvertently forwards a message that is in violation of FCC rules, who is primarily accountable for the rules violation?

Select	Answer
A	The control operators of all the stations in the system
B	The control operators of all the stations in the system not authenticating the source from which they accept communications
C	The control operator of the packet bulletin board station
D	The control operator of the originating station

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

4. - E1C03

How do the control operator responsibilities of a station under automatic control differ from one under local control?

Select	Answer
A	Under local control a control operator is not required to be present at a control point
B	Under automatic control there is no control operator
C	Under automatic control the control operator is not required to be present at the control point
D	Under local control there is no control operator

5. - E1D04

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

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

6. - E1E07

What should a VE do if a candidate fails to comply with the examiner's instructions during an amateur operator license examination?

Select	Answer
A	Immediately terminate everyone's examination and close the session
B	Warn the candidate that continued failure to comply will result in termination of the examination
C	Immediately terminate the candidate's examination
D	Allow the candidate to complete the examination, but invalidate the results

7. - E1F04

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

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

8. - E2A04

What is meant by the term mode? as applied to an amateur radio satellite?

Select	Answer
A	Whether the satellite is in a polar or equatorial orbit
B	The satellite's uplink and downlink frequency bands
C	Whether the satellite is in a low earth or geostationary orbit
D	The satellite's orientation with respect to the Earth

9. - E2B08

What technique allows commercial analog TV receivers to be used for fast-scan TV operations on the 70 cm band?

Select	Answer
A	Using converted satellite TV dishes
B	Transmitting on channels shared with cable TV
C	Using USB and demodulating the signal with a computer sound card
D	Transmitting on the abandoned TV channel 2

10. - E2C11

How should you generally identify your station when attempting to contact a DX station during a contest or in a pileup?

Select	Answer
A	Send your full call sign and grid square
B	Send your full call sign once or twice
C	Send the call sign of the DX station three times, the words this is,then your call sign three times
D	Send only the last two letters of your call sign until you make contact

11. - E2D07

What digital protocol is used by APRS?

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

12. - E2E10

Which of these digital modes has the narrowest bandwidth?

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

13. - E3A11

What is a typical range for tropospheric propagation of microwave signals?

Select	Answer
A	1200 miles
B	2500 miles
C	10 miles to 50 miles
D	100 miles to 300 miles

14. - E3B03

What is the best time of day for transequatorial propagation?

Select	Answer
A	Noon
B	Afternoon or early evening
C	Morning
D	Late at night

15. - E3C14

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

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

16. - E4A04

How is the compensation of an oscilloscope probe typically adjusted?

Select	Answer
A	A high frequency sine wave is displayed and the probe is adjusted for maximum amplitude
B	A frequency standard is displayed and the probe is adjusted until the deflection time is accurate
C	A DC voltage standard is displayed and the probe is adjusted until the displayed voltage is accurate
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. - E4B11

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

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

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

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

20. - E4E03

Which of the following signals might a receiver noise blanker be able to remove from desired signals?

Select	Answer
A	Signals that are constant at all IF levels
B	Signals that appear across a wide bandwidth
C	Signals that appear at one IF but not another
D	Signals that have a sharply peaked frequency distribution

21. - E5A04

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

Select	Answer
A	High compared to the circuit resistance
B	Low compared to the circuit resistance
C	Approximately equal to circuit resistance
D	Approximately equal to inductive 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. - 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 8
D	Point 1

24. - E5D05

What is the power factor of an RL circuit having a 30-degree phase angle between the voltage and the current?

Select	Answer
A	0.577
B	0.866
C	0.5
D	1.73

25. - E6A02

Which of the following semiconductor materials contains excess free electrons?

Select	Answer
A	Insulated gate
B	P-type
C	Bipolar
D	N-type

26. - E6B09

What is a common use for point-contact diodes?

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

27. - E6C06

Why do CMOS digital integrated circuits have high immunity to noise on the input signal or power supply?

Select	Answer
A	Bandwidth is very limited
B	The input switching threshold is about two times the power supply voltage
C	The input switching threshold is about one-half the power supply voltage
D	Large bypass capacitance is inherent

28. - E6D11

Which type of core material decreases inductance when inserted into a coil?

Select	Answer
A	Brass
B	Ferrite
C	Ceramic
D	Powdered iron

29. - E6E01

Why is gallium arsenide (GaAs) useful for semiconductor devices operating at UHF and higher frequencies?

Select	Answer
A	Higher electron mobility
B	Higher noise figures
C	Lower transconductance
D	Lower junction voltage drop

30. - E6F05

Which describes an optical shaft encoder?

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

31. - E7A03

Which of the following can divide the frequency of a pulse train by 2?

Select	Answer
A	A flip-flop
B	A multiplexer
C	An XOR gate
D	An OR gate

32. - E7B05

What can be done to prevent unwanted oscillations in an RF power amplifier?

Select	Answer
A	Use a phase inverter in the output filter
B	Tune both the input and output for maximum power
C	Tune the stage for maximum SWR
D	Install parasitic suppressors and/or neutralize the stage

33. - E7C08

Which of the following factors has the greatest effect on the bandwidth and response shape of a crystal ladder filter?

Select	Answer
A	The gain of the RF stage preceding the filter
B	The relative frequencies of the individual crystals
C	The amplitude of the signals passing through the filter
D	The DC voltage applied to the quartz crystal

34. - E7D05

Which of the following types of linear voltage regulator places a constant load on the unregulated voltage source?

Select	Answer
A	A shunt regulator
B	A shunt current source
C	A series regulator
D	A constant current source

35. - E7E04

What is one way a single-sideband phone signal can be generated?

Select	Answer
A	By using a loop modulator followed by a mixer
B	By driving a product detector with a DSB signal
C	By using a reactance modulator followed by a mixer
D	By using a balanced modulator followed by a filter

36. - E7F07

What function is performed by a Fast Fourier Transform?

Select	Answer
A	Converting digital signals to analog form
B	Converting 8-bit data to 16-bit data
C	Converting digital signals from the time domain to the frequency domain
D	Converting analog signals to digital form

37. - E7G08

How does the gain of an ideal operational amplifier vary with frequency?

Select	Answer
A	It does not vary with frequency
B	It increases linearly with increasing frequency
C	It decreases logarithmically with increasing frequency
D	It decreases linearly with increasing frequency

38. - E7H06

Which of the following oscillator circuits are commonly used in VFOs?

Select	Answer
A	Negative feedback and balanced feedback
B	Armstrong and deForest
C	Pierce and Zener
D	Colpitts and Hartley

39. - E8A02

Which of the following is a type of analog-to-digital conversion?

Select	Answer
A	Level shifting
B	Harmonic regeneration
C	Successive approximation
D	Phase reversal

40. - E8B07

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

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

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 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
B	Baudot uses 7 data bits per character, ASCII uses 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes
C	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
D	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

43. - E9A04

Which of the following factors affect the feed point impedance of an antenna?

Select	Answer
A	Antenna height
B	The input power level
C	Transmission line length
D	The settings of an antenna tuner at the transmitter

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

45. - E9C06

What is the effect of adding a terminating resistor to a rhombic antenna?

Select	Answer
A	It reflects the standing waves on the antenna elements back to the transmitter
B	It changes the radiation pattern from horizontal to vertical polarization
C	It decreases the ground loss
D	It changes the radiation pattern from bidirectional to unidirectional

46. - E9D07

What is an advantage of using top loading in a shortened HF vertical antenna?

Select	Answer
A	Improved radiation efficiency
B	Higher losses
C	Greater structural strength
D	Lower Q

47. - E9E01

What system matches a higher-impedance transmission line to a lower-impedance antenna by connecting the line to the driven element in two places spaced a fraction of a wavelength each side of element center?

Select	Answer
A	The omega matching system
B	The gamma matching system
C	The delta matching system
D	The stub matching system

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

49. - E9G08

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

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

50. - E9H03

What is Receiving Directivity Factor (RDF)?

Select	Answer
A	Forward gain compared to average gain over the entire hemisphere
B	Relative directivity compared to isotropic
C	Forward gain compared to the gain in the reverse direction
D	Relative directivity compared to a dipole

Figure E5-1