US Amateur Radio - Amateur Extra (Element 4, 2016-2020) Practice Test

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1. - E1A09

What is the first action you should take if your digital message forwarding station inadvertently forwards a communication that violates FCC rules?

Select	Answer
A	Notify the originating station that the communication does not comply with FCC rules
B	Discontinue forwarding the communication as soon as you become aware of it
C	Notify the nearest FCC Field Engineer's office
D	Discontinue forwarding all messages

2. - E1B03

Within what distance must an amateur station protect an FCC monitoring facility from harmful interference?

Select	Answer
A	3 miles
B	30 miles
C	1 mile
D	10 miles

3. - E1C13

Which of the following is required in order to operate in accordance with CEPT rules in foreign countries where permitted?

Select	Answer
A	The U.S. embassy must approve of your operation
B	You must bring a copy of FCC Public Notice DA 11-221
C	You must append "/CEPT" to your call sign
D	You must identify in the official language of the country in which you are operating

4. - E1D02

What is the amateur satellite service?

Select	Answer
A	A radio navigation service using satellites for the purpose of self training, intercommunication and technical studies carried out by amateurs
B	A radio communications service using stations on Earth satellites for public service broadcast
C	A spacecraft launching service for amateur-built satellites
D	A radio communications service using amateur radio stations on satellites

5. - 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 submit the documents to the coordinating VEC for grading
C	They must collect and send the documents to the FCC according to instructions
D	They must collect and send the documents to the NCVEC for grading

6. - E1F04

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

Select	Answer
A	A line roughly parallel to and east of the U.S. Pacific coastline
B	A line roughly parallel to and north of the U.S.-Mexican border and Gulf coastline
C	A line roughly parallel to and south of the U.S.-Canadian border
D	A line roughly parallel to and west of the U.S. Atlantic coastline

7. - E2A10

Why may the received signal from an amateur satellite exhibit a rapidly repeating fading effect?

Select	Answer
A	Because of the Doppler Effect
B	Because of ionospheric absorption
C	Because of the satellite's low orbital altitude
D	Because the satellite is spinning

8. - E2B14

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

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

9. - E2C12

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	Switch to a lower frequency HF band
C	Switch to a higher frequency HF band
D	Wait 24 hours before attempting another communication on the band

10. - E2D11

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

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

11. - E2E03

How is the timing of JT65 contacts organized?

Select	Answer
A	By exchanging ACK/NAK packets
B	Stations take turns on alternate days
C	It depends on the lunar phase
D	Alternating transmissions at 1 minute intervals

12. - E3A07

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

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

13. - E3B10

What is the cause of gray-line propagation?

Select	Answer
A	In darkness, solar absorption drops greatly while atmospheric ionization remains steady
B	At mid-afternoon, the Sun heats the ionosphere decreasing radio wave refraction and the MUF
C	At midday, the Sun super heats the ionosphere causing increased refraction of radio waves
D	At twilight and sunrise, D-layer absorption is low while E-layer and F-layer propagation remains high

14. - 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	UV emissions at 304 angstroms, correlated to solar flux index
C	The solar emission at 304 GHz, correlated to X-Ray flare levels
D	The ratio of X-Ray flux to radio flux, correlated to sunspot number

15. - E4A11

Which of the following is good practice when using an oscilloscope probe?

Select	Answer
A	All of these choices are correct
B	Never use a high impedance probe to measure a low impedance circuit
C	Keep the signal ground connection of the probe as short as possible
D	Never use a DC-coupled probe to measure an AC circuit

16. - E4B04

If a frequency counter with a specified accuracy of +/- 0.1 ppm reads 146,520,000 Hz, what is the most the actual frequency being measured could differ from the reading?

Select	Answer
A	0.1 MHz
B	1.4652 kHz
C	1.4652 Hz
D	14.652 Hz

17. - E4C09

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

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

18. - E4D06

What is the term for unwanted signals generated by the mixing of two or more signals?

Select	Answer
A	Neutralization
B	Adjacent channel interference
C	Intermodulation interference
D	Amplifier desensitization

19. - E4E06

What is a major cause of atmospheric static?

Select	Answer
A	Geomagnetic storms
B	Meteor showers
C	Solar radio frequency emissions
D	Thunderstorms

20. - E5A02

What is resonance in an electrical circuit?

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

21. - E5B02

What is the term for the time it takes for a charged capacitor in an RC circuit to discharge to 36.8% of its initial voltage?

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

22. - E5C09

When using rectangular coordinates to graph the impedance of a circuit, what does the horizontal axis represent?

Select	Answer
A	Resistive component
B	The sum of the reactive and resistive components
C	The difference between the resistive and reactive components
D	Reactive component

23. - E5D15

What is the power factor of an R-L circuit having a 45 degree phase angle between the voltage and the current?

Select	Answer
A	0.5
B	0.866
C	0.707
D	1.0

24. - E6A03

Why does a PN-junction diode not conduct current when reverse biased?

Select	Answer
A	Holes in P-type material and electrons in the N-type material are separated by the applied voltage, widening the depletion region
B	Only P-type semiconductor material can conduct current
C	Excess holes in P-type material combine with the electrons in N-type material, converting the entire diode into an insulator
D	Only N-type semiconductor material can conduct current

25. - E6B06

Which of the following is a common use of a hot-carrier diode?

Select	Answer
A	As a VHF/UHF mixer or detector
B	As a variable capacitance in an automatic frequency control circuit
C	As balanced mixers in FM generation
D	As a constant voltage reference in a power supply

26. - E6C03

What is tri-state logic?

Select	Answer
A	Logic devices that utilize ternary math
B	Logic devices with 0, 1, and high impedance output states
C	Low power logic devices designed to operate at 3 volts
D	Proprietary logic devices manufactured by Tri-State Devices

27. - E6D13

What is the primary cause of inductor self-resonance?

Select	Answer
A	Non-linear core hysteresis
B	Inter-turn capacitance
C	The skin effect
D	Inductive kickback

28. - E6E10

What is the packaging technique in which leadless components are soldered directly to circuit boards?

Select	Answer
A	Stripped lead
B	Surface mount
C	Direct soldering
D	Virtual lead mounting

29. - E6F12

What absorbs the energy from light falling on a photovoltaic cell?

Select	Answer
A	Protons
B	Electrons
C	Photons
D	Holes

30. - E7A03

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

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

31. - E7B03

Which of the following components form the output of a class D amplifier circuit?

Select	Answer
A	A high-pass filter to compensate for low gain at low frequencies
B	A matched load resistor to prevent damage by switching transients
C	A temperature compensating load resistor to improve linearity
D	A low-pass filter to remove switching signal components

32. - E7C04

How does an impedance-matching circuit transform a complex impedance to a resistive impedance?

Select	Answer
A	It cancels the reactive part of the impedance and changes the resistive part to a desired value
B	Network resistances are substituted for load resistances and reactances are matched to the resistances
C	It introduces negative resistance to cancel the resistive part of impedance
D	It introduces transconductance to cancel the reactive part of impedance

33. - E7D08

What type of circuit is shown in Figure E7-3?

Select	Answer
A	Emitter follower
B	Switching voltage regulator
C	Grounded emitter amplifier
D	Linear voltage regulator

34. - E7E04

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

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

35. - E7F05

How frequently must an analog signal be sampled by an analog-to-digital converter so that the signal can be accurately reproduced?

Select	Answer
A	At the same rate as the highest frequency component of the signal
B	At half the rate of the highest frequency component of the signal
C	At twice the rate of the highest frequency component of the signal
D	At four times the rate of the highest frequency component of the signal

36. - E7G06

Which of the following is the most appropriate use of an op-amp active filter?

Select	Answer
A	For smoothing power supply output
B	As a low-pass filter used between a transmitter and a transmission line
C	As an audio filter in a receiver
D	As a high-pass filter used to block RFI at the input to receivers

37. - E7H12

Which of the following must be done to insure that a crystal oscillator provides the frequency specified by the crystal manufacturer?

Select	Answer
A	Bias the crystal at a specified voltage
B	Provide the crystal with a specified parallel capacitance
C	Bias the crystal at a specified current
D	Provide the crystal with a specified parallel inductance

38. - E8A09

How many levels can an analog-to-digital converter with 8 bit resolution encode?

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

39. - E8B07

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

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

40. - E8C10

What is an advantage of Gray code in digital communications where symbols are transmitted as multiple bits

Select	Answer
A	It has more resolution than simple binary
B	It increases security
C	It has more possible states than simple binary
D	It facilitates error detection

41. - 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 6 data bits per character, ASCII uses 7 or 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 7 data bits per character, ASCII uses 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes

42. - E9A17

What is the effective radiated power of a repeater station with 200 watts transmitter power output, 2 dB feed line loss, 2.8 dB duplexer loss, 1.2 dB circulator loss, and 7 dBi antenna gain?

Select	Answer
A	159 watts
B	252 watts
C	63.2 watts
D	632 watts

43. - E9B16

How many elevation lobes appear in the forward direction of the antenna radiation pattern shown in Figure E9-2?

Select	Answer
A	3
B	4
C	7
D	1

44. - E9C10

Which of the following describes a Zepp antenna?

Select	Answer
A	An end fed dipole antenna
B	A vertical array capable of quickly changing the direction of maximum radiation by changing phasing lines
C	An omni-directional antenna commonly used for satellite communications
D	A dipole constructed from zip cord

45. - E9D02

How can linearly polarized Yagi antennas be used to produce circular polarization?

Select	Answer
A	Arrange two Yagis perpendicular to each other with the driven elements at the same point on the boom fed 90 degrees out of phase
B	Arrange two Yagis collinear to each other with the driven elements fed 180 degrees out of phase
C	Stack two Yagis fed 90 degrees out of phase to form an array with the respective elements in parallel planes
D	Stack two Yagis fed in phase to form an array with the respective elements in parallel planes

46. - E9E10

Which of these choices is an effective way to match an antenna with a 100 ohm feed point impedance to a 50 ohm coaxial cable feed line?

Select	Answer
A	Insert a 1/4-wavelength piece of 75 ohm coaxial cable transmission line in series between the antenna terminals and the 50 ohm feed cable
B	Insert a 1/2 wavelength piece of 300 ohm twin-lead in series between the antenna terminals and the 50 ohm feed cable
C	Connect 1/2 wavelength shorted stub of 75 ohm cable in parallel with the 50 ohm cable where it attaches to the antenna
D	Connect a 1/4-wavelength open stub of 300 ohm twin-lead in parallel with the coaxial feed line where it connects to the antenna

47. - E9F03

Why is the physical length of a coaxial cable transmission line shorter than its electrical length?

Select	Answer
A	The surge impedance is higher in a parallel feed line
B	The characteristic impedance is higher in a parallel feed line
C	Skin effect is less pronounced in the coaxial cable
D	Electrical signals move more slowly in a coaxial cable than in air

48. - E9G04

What are the two families of circles and arcs that make up a Smith chart?

Select	Answer
A	Resistance and voltage
B	Reactance and voltage
C	Voltage and impedance
D	Resistance and reactance

49. - E9H09

Which of the following describes the construction of a receiving loop antenna?

Select	Answer
A	A vertical antenna coupled to a feed line through an inductive loop of wire
B	One or more turns of wire wound in the shape of a large open coil
C	A small coil of wire tightly wound around a toroidal ferrite core
D	A large circularly polarized antenna

50. - E0A08

What does SAR measure?

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

Figure E7-3

Figure E9-2