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

2. - E1B06

Which of the following additional rules apply if you are installing an amateur station antenna at a site at or near a public use airport?

Select	Answer
A	No special rules apply if your antenna structure will be less than 300 feet in height
B	You must file an Environmental Impact Statement with the EPA before construction begins
C	You must obtain a construction permit from the airport zoning authority
D	You may have to notify the Federal Aviation Administration and register it with the FCC as required by Part 17 of FCC rules

3. - E1C11

Which of the following operating arrangements allows an FCC-licensed U.S. citizen to operate in many European countries, and alien amateurs from many European countries to operate in the U.S.?

Select	Answer
A	IARP agreement
B	CEPT agreement
C	All of these choices are correct
D	ITU reciprocal license

4. - E1D09

Which UHF amateur service bands have frequencies available for a space station?

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

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 NCVEC for grading
D	They must collect and send the documents to the FCC according to instructions

6. - E1F11

Which of the following best describes one of the standards that must be met by an external RF power amplifier if it is to qualify for a grant of FCC certification?

Select	Answer
A	It must produce full legal output when driven by not more than 5 watts of mean RF input power
B	It must exhibit a gain of 0 dB or less over its full output range
C	It must be capable of external RF switching between its input and output networks
D	It must satisfy the FCC's spurious emission standards when operated at the lesser of 1500 watts or its full output power

7. - E2A11

What type of antenna can be used to minimize the effects of spin modulation and Faraday rotation?

Select	Answer
A	A log-periodic dipole array
B	An isotropic antenna
C	A circularly polarized antenna
D	A linearly polarized antenna

8. - E2B03

How is an interlaced scanning pattern generated in a fast-scan (NTSC) television system?

Select	Answer
A	By scanning each field from bottom to top
B	By scanning odd numbered lines in one field and even numbered lines in the next
C	By scanning two fields simultaneously
D	By scanning lines from left to right in one field and right to left in the next

9. - 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 only the last two letters of your call sign until you make contact
C	Send the call sign of the DX station three times, the words "this is", then your call sign three times
D	Send your full call sign once or twice

10. - E2D06

Which of the following describes a method of establishing EME contacts?

Select	Answer
A	High speed CW identification to avoid fading
B	Judging optimum transmission times by monitoring beacons reflected from the Moon
C	Storing and forwarding digital messages
D	Time synchronous transmissions alternately from each station

11. - E2E06

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

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

12. - E3A15

What is an electromagnetic wave?

Select	Answer
A	A wave consisting of an electric field and a magnetic field oscillating at right angles to each other
B	A wave of alternating current, in the core of an electromagnet
C	A wave consisting of two magnetic fields at right angles to each other
D	A wave consisting of two electric fields at parallel right angles to each other

13. - E3B07

Which of the following could account for hearing an echo on the received signal of a distant station?

Select	Answer
A	High D layer absorption
B	Meteor scatter
C	Receipt of a signal by more than one path
D	Transmit frequency is higher than the MUF

14. - E3C13

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

Select	Answer
A	Horizontal
B	Elliptical
C	Vertical
D	Circular

15. - E4A08

Which of the following instrument would be best for measuring the SWR of a beam antenna?

Select	Answer
A	A spectrum analyzer
B	An antenna analyzer
C	An ohmmeter
D	A Q meter

16. - E4B17

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

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

17. - E4C06

A CW receiver with the AGC off has an equivalent input noise power density of -174 dBm/Hz. What would be the level of an unmodulated carrier input to this receiver that would yield an audio output SNR of 0 dB in a 400 Hz noise bandwidth?

Select	Answer
A	-164 dBm
B	-148 dBm
C	-155 dBm
D	-174 dBm

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	Amplifier desensitization
D	Intermodulation interference

19. - E4E02

Which of the following types of receiver noise can often be reduced with a DSP noise filter?

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

20. - E5A17

What is the result of increasing the Q of an impedance-matching circuit?

Select	Answer
A	Matching bandwidth is increased
B	It has no effect on impedance matching
C	Matching range is increased
D	Matching bandwidth is decreased

21. - E5B05

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

Select	Answer
A	It is unchanged
B	The magnitude of the susceptance is the reciprocal of the magnitude of the reactance
C	The sign is reversed
D	It is shifted by 90 degrees

22. - E5C11

What do the two numbers that are used to define a point on a graph using rectangular coordinates represent?

Select	Answer
A	The coordinate values along the horizontal and vertical axes
B	The magnitude and phase of the point
C	The tangent and cotangent values
D	The sine and cosine values

23. - E5D05

Which parasitic characteristic increases with conductor length?

Select	Answer
A	Permeability
B	Permittivity
C	Malleability
D	Inductance

24. - E6A03

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

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

25. - E6B05

What characteristic of a PIN diode makes it useful as an RF switch or attenuator?

Select	Answer
A	A large region of intrinsic material
B	Reverse bias controls its forward voltage drop
C	Extremely high reverse breakdown voltage
D	Ability to dissipate large amounts of power

26. - E6C03

What is tri-state logic?

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

27. - E6D05

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

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

28. - E6E07

Which of the following is typically used to construct a MMIC-based microwave amplifier?

Select	Answer
A	Point-to-point construction
B	Ground-plane construction
C	Microstrip construction
D	Wave-soldering construction

29. - E6F09

What is the efficiency of a photovoltaic cell?

Select	Answer
A	The open-circuit voltage divided by the short-circuit current under full illumination
B	The relative fraction of light that is converted to current
C	The effective payback period
D	The output RF power divided by the input DC power

30. - E7A10

What is a truth table?

Select	Answer
A	A list of inputs and corresponding outputs for a digital device
B	A table of logic symbols that indicate the high logic states of an op-amp
C	A table of logic symbols that indicate the logic states of an op-amp
D	A diagram showing logic states when the digital device output is true

31. - E7B16

What is the effect of intermodulation products in a linear power amplifier?

Select	Answer
A	Low efficiency
B	Transmission of spurious signals
C	Creation of parasitic oscillations
D	All of these choices are correct

32. - E7C09

What is a Jones filter as used as part of an HF receiver IF stage?

Select	Answer
A	An automatic notch filter
B	A filter that removes impulse noise E7C10 (B) Which of the following filters would be the best choice for use in a 2 meter repeater duplexer? A. A crystal filter B. A cavity filter C. A DSP filter D. An L-C filter
C	A variable bandwidth crystal lattice filter
D	A special filter that emphasizes image responses

33. - E7D02

What is one characteristic of a switching electronic voltage regulator?

Select	Answer
A	The controlled device's duty cycle is changed to produce a constant average output voltage
B	It gives a ramp voltage at its output
C	It is generally less efficient than a linear regulator
D	The resistance of a control element is varied in direct proportion to the line voltage or load current

34. - E7E04

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

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

35. - E7F09

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

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

36. - E7G04

What is meant by the term op-amp input offset voltage?

Select	Answer
A	The difference between the output voltage of the op-amp and the input voltage required in the immediately following stage
B	The potential between the amplifier input terminals of the op-amp in an open loop condition
C	The output voltage of the op-amp minus its input voltage
D	The differential input voltage needed to bring the open loop output voltage to zero

37. - E7H14

What is a phase-locked loop circuit?

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

38. - E8A13

Which of these methods is commonly used to convert analog signals to digital signals?

Select	Answer
A	Level shifting
B	Phase reversal
C	Harmonic regeneration
D	Sequential sampling

39. - E8B05

What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus-or-minus 5 kHz when the maximum modulation frequency is 3 kHz?

Select	Answer
A	60
B	0.167
C	1.67
D	0.6

40. - E8C10

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

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

41. - E8D09

What is considered a good minimum IMD level for an idling PSK signal?

Select	Answer
A	+15 dB
B	-30 dB
C	-20 dB
D	+10 dB

42. - E9A14

What is meant by the radiation resistance of an antenna?

Select	Answer
A	The value of a resistance that would dissipate the same amount of power as that radiated from an antenna
B	The specific impedance of the antenna
C	The combined losses of the antenna elements and feed line
D	The resistance in the atmosphere that an antenna must overcome to be able to radiate a signal

43. - E9B14

What type of information can be obtained by submitting the details of a proposed new antenna to a modeling program?

Select	Answer
A	SWR vs frequency charts
B	Polar plots of the far field elevation and azimuth patterns
C	Antenna gain
D	All of these choices are correct

44. - E9C03

What is the radiation pattern of two 1/4 wavelength vertical antennas spaced a 1/2 wavelength apart and fed in phase?

Select	Answer
A	A Figure-8 broadside to the axis of the array
B	Omni-directional
C	A Figure-8 end-fire along the axis of the array
D	Cardioid

45. - E9D11

Which of the following types of conductors would be best for minimizing losses in a station's RF ground system?

Select	Answer
A	A resistive wire, such as spark plug wire
B	A cable with six or seven 18 gauge conductors in parallel
C	A single 12 gauge or 10 gauge stainless steel wire
D	A wide flat copper strap

46. - E9E13

What is a use for a Wilkinson divider?

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

47. - E9F03

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

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

48. - E9G09

What third family of circles is often added to a Smith chart during the process of solving problems?

Select	Answer
A	Coaxial-length circles
B	Antenna-length circles
C	Radiation-pattern circles
D	Standing wave ratio circles

49. - E9H09

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

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

50. - E0A07

How may dangerous levels of carbon monoxide from an emergency generator be detected?

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