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

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1. - E1A04

With your transceiver displaying the carrier frequency of phone signals, you hear a DX station calling CQ on 3.601 MHz LSB. Is it legal to return the call using lower sideband on the same frequency?

Select	Answer
A	Yes, because the displayed frequency is within the 75 meter phone band segment
B	No, the sideband will extend beyond the edge of the phone band segment
C	Yes, because the DX station initiated the contact
D	No, U.S. stations are not permitted to use phone emissions below 3.610 MHz

2. - E1B11

What is the permitted mean power of any spurious emission relative to the mean power of the fundamental emission from a station transmitter or external RF amplifier installed after January 1, 2003 and transmitting on a frequency below 30 MHZ?

Select	Answer
A	At least 63 dB below
B	At least 53 dB below
C	At least 73 dB below
D	At least 43 dB below

3. - E1C05

When may an automatically controlled station originate third party communications?

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

4. - E1D02

What is the amateur satellite service?

Select	Answer
A	A radio communications service using amateur radio stations on satellites
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 navigation service using satellites for the purpose of self training, intercommunication and technical studies carried out by amateurs

5. - 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	Allow the candidate to complete the examination, but invalidate the results
D	Immediately terminate the candidate's examination

6. - E1F06

Under what circumstances might the FCC issue a Special Temporary Authority (STA) to an amateur station?

Select	Answer
A	To provide for experimental amateur communications
B	To allow regular operation on Land Mobile channels
C	To provide additional spectrum for personal use
D	To provide temporary operation while awaiting normal licensing

7. - E2A04

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

Select	Answer
A	The satellite's orientation with respect to the Earth
B	The type of signals that can be relayed through the satellite
C	Whether the satellite is in a polar or equatorial orbit
D	The satellite's uplink and downlink frequency bands

8. - E2B02

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

Select	Answer
A	1080
B	30
C	525
D	60

9. - E2C06

During a VHF/UHF contest, in which band segment would you expect to find the highest level of activity?

Select	Answer
A	In the weak signal segment of the band, with most of the activity near the calling frequency
B	In the middle of each band, usually on the national calling frequency
C	At the top of each band, usually in a segment reserved for contests
D	In the middle of the band, usually 25 kHz above the national calling frequency

10. - E2D08

What type of packet frame is used to transmit APRS beacon data?

Select	Answer
A	Acknowledgement
B	Unnumbered Information
C	Connect
D	Disconnect

11. - E2E12

Which type of control is used by stations using the Automatic Link Enable (ALE) protocol?

Select	Answer
A	Local
B	ALE can use any type of control
C	Automatic
D	Remote

12. - E3A13

Which emission mode is best for aurora propagation?

Select	Answer
A	SSB
B	RTTY
C	FM
D	CW

13. - E3B11

At what time of day is Sporadic-E propagation most likely to occur?

Select	Answer
A	Around sunset
B	Any time
C	Around sunrise
D	Early evening

14. - E3C13

What type of polarization is best for ground-wave propagation?

Select	Answer
A	Circular
B	Horizontal
C	Vertical
D	Elliptical

15. - E4A04

What determines the upper frequency limit for a computer soundcard-based oscilloscope program?

Select	Answer
A	Amount of memory on the soundcard
B	Analog-to-digital conversion speed of the soundcard
C	Q of the interface of the interface circuit
D	All of these choices are correct

16. - E4B17

What three test loads are used to calibrate a standard RF vector network analyzer?

Select	Answer
A	50 ohms through 1/8 wavelength, 1/4 wavelength, and 1/2 wavelength of coaxial cable
B	Short circuit, open circuit, and resonant circuit
C	50 ohms, 75 ohms, and 90 ohms
D	Short circuit, open circuit, and 50 ohms

17. - E4C04

How is the noise figure of a receiver defined?

Select	Answer
A	The ratio of thermal noise to atmospheric noise
B	The ratio in dB of the noise generated by the receiver to the theoretical minimum noise
C	The ratio of atmospheric noise to phase noise
D	The ratio of the noise bandwidth in Hertz to the theoretical bandwidth of a resistive network

18. - E4D08

What causes intermodulation in an electronic circuit?

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

19. - E4E01

Which of the following types of receiver noise can often be reduced by use of a receiver noise blanker?

Select	Answer
A	All of these choices are correct
B	Ignition noise
C	Broadband white noise
D	Heterodyne interference

20. - E5A01

What can cause the voltage across reactances in series to be larger than the voltage applied to them?

Select	Answer
A	Conductance
B	Capacitance
C	Resistance
D	Resonance

21. - E5B09

What is the relationship between the current through a capacitor and the voltage across a capacitor?

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

22. - 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	Maidenhead grid
C	Faraday grid
D	Polar coordinates

23. - E5D04

Why are short connections necessary at microwave frequencies?

Select	Answer
A	Because of ground reflections
B	To reduce phase shift along the connection
C	To reduce noise figure
D	To increase neutralizing resistance

24. - E6A13

What do the initials CMOS stand for?

Select	Answer
A	Common Mode Oscillating System
B	Common Mode Organic Silicon
C	Complementary Mica-Oxide Silicon
D	Complementary Metal-Oxide Semiconductor

25. - E6B13

What type of bias is required for an LED to emit light?

Select	Answer
A	Inductive bias
B	Reverse bias
C	Zero bias
D	Forward bias

26. - E6C04

What is the primary advantage of tri-state logic?

Select	Answer
A	Ability to connect many device outputs to a common bus
B	High speed operation
C	Low power consumption
D	More efficient arithmetic operations

27. - E6D14

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

Select	Answer
A	Powdered-iron
B	Ceramic
C	Brass
D	Ferrite

28. - E6E01

Which of the following is true of a charge-coupled device (CCD)?

Select	Answer
A	It is used in a battery charger circuit
B	Its phase shift changes rapidly with frequency
C	It is a CMOS analog-to-digital converter
D	It samples an analog signal and passes it in stages from the input to the output

29. - E6F14

Which of the following is true of LCD displays?

Select	Answer
A	All of these choices are correct
B	They are hard to view in high ambient light conditions
C	They only display alphanumeric symbols
D	They may be hard view through polarized lenses

30. - E7A03

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

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

31. - E7B09

Which of the following describes how the loading and tuning capacitors are to be adjusted when tuning a vacuum tube RF power amplifier that employs a Pi-network output circuit?

Select	Answer
A	The loading capacitor is adjusted to minimum plate current while alternately adjusting the tuning capacitor for maximum allowable plate current
B	The tuning capacitor is set to maximum capacitance and the loading capacitor is adjusted for minimum plate permissible current
C	The loading capacitor is set to maximum capacitance and the tuning capacitor is adjusted for minimum allowable plate current
D	The tuning capacitor is adjusted for minimum plate current, and the loading capacitor is adjusted for maximum permissible plate current

32. - E7C05

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

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

33. - E7D04

Which of the following types of linear voltage regulator usually make the most efficient use of the primary power source?

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

34. - 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 using a balanced modulator followed by a filter
C	By driving a product detector with a DSB signal
D	By using a reactance modulator followed by a mixer

35. - E7F09

Why is an anti-aliasing digital filter required in a digital decimator?

Select	Answer
A	It peaks the response of the decimator, improving bandwidth
B	It removes low frequency signal components to eliminate the need for DC restoration
C	It notches out the sampling frequency to avoid sampling errors
D	It removes high-frequency signal components which would otherwise be reproduced as lower frequency components

36. - E7G12

What is an integrated circuit operational amplifier?

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

37. - E7H14

What is a phase-locked loop circuit?

Select	Answer
A	An electronic circuit consisting of a precision push-pull amplifier with a differential input
B	An electronic servo loop consisting of a phase detector, a low-pass filter, a voltage-controlled oscillator, and a stable reference oscillator
C	An electronic servo loop consisting of a ratio detector, reactance modulator, and voltage-controlled oscillator
D	An electronic circuit also known as a monostable multivibrator

38. - E8A08

Why would a direct or flash conversion analog-to-digital converter be useful for a software defined radio?

Select	Answer
A	Very high speed allows digitizing high frequencies
B	All of these choices are correct
C	Very low power consumption decreases frequency drift
D	Immunity to out of sequence coding reduces spurious responses

39. - E8B02

How does the modulation index of a phase-modulated emission vary with RF carrier frequency (the modulated frequency)?

Select	Answer
A	It does not depend on the RF carrier frequency
B	It varies with the square root of the RF carrier frequency
C	It decreases as the RF carrier frequency increases
D	It increases as the RF carrier frequency increases

40. - E8C04

What technique is used to minimize the bandwidth requirements of a PSK31 signal?

Select	Answer
A	Use of sinusoidal data pulses
B	Zero-sum character encoding
C	Use of trapezoidal data pulses
D	Reed-Solomon character encoding

41. - E8D01

Why are received spread spectrum signals resistant to interference?

Select	Answer
A	If interference is detected by the receiver it will signal the transmitter to change frequencies
B	The receiver is always equipped with a digital blanker
C	The high power used by a spread spectrum transmitter keeps its signal from being easily overpowered
D	Signals not using the spread spectrum algorithm are suppressed in the receiver

42. - E9A06

How does the beamwidth of an antenna vary as the gain is increased?

Select	Answer
A	It increases arithmetically
B	It is essentially unaffected
C	It decreases
D	It increases geometrically

43. - E9B11

What is a disadvantage of decreasing the number of wire segments in an antenna model below the guideline of 10 segments per half-wavelength?

Select	Answer
A	The computed feed point impedance may be incorrect
B	Ground conductivity will not be accurately modeled
C	The antenna will become mechanically unstable
D	The resulting design will favor radiation of harmonic energy

44. - E9C09

What is a G5RV antenna?

Select	Answer
A	A multi-band trap antenna
B	A wide band dipole using shorted coaxial cable for the radiating elements and fed with a 4:1 balun
C	A phased array antenna consisting of multiple loops
D	A multi-band dipole antenna fed with coax and a balun through a selected length of open wire transmission line

45. - E9D01

How does the gain of an ideal parabolic dish antenna change when the operating frequency is doubled?

Select	Answer
A	Gain is multiplied by 0.707
B	Gain increases by 6 dB
C	Gain increases by 3 dB
D	Gain does not change

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 1/2 wavelength piece of 300 ohm twin-lead in series between the antenna terminals and the 50 ohm feed cable
B	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
C	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
D	Connect 1/2 wavelength shorted stub of 75 ohm cable in parallel with the 50 ohm cable where it attaches 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	Skin effect is less pronounced in the coaxial cable
C	Electrical signals move more slowly in a coaxial cable than in air
D	The characteristic impedance is higher in a parallel feed line

48. - 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

49. - E9H07

Why is it advisable to use an RF attenuator on a receiver being used for direction finding?

Select	Answer
A	It compensates for the effects of an isotropic antenna, thereby improving directivity
B	It reduces loss of received signals caused by antenna pattern nulls, thereby increasing sensitivity
C	It narrows the bandwidth of the received signal to improve signal to noise ratio
D	It prevents receiver overload which could make it difficult to determine peaks or nulls

50. - E0A04

When evaluating a site with multiple transmitters operating at the same time, the operators and licensees of which transmitters are responsible for mitigating over-exposure situations?

Select	Answer
A	Each transmitter that produces 5 percent or more of its MPE limit at accessible locations
B	Only the most powerful transmitter
C	Only commercial transmitters
D	Each transmitter operating with a duty-cycle greater than 50 percent