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

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1. - E1A02

When using a transceiver that displays the carrier frequency of phone signals, which of the following displayed frequencies represents the lowest frequency at which a properly adjusted LSB emission will be totally within the band?

Select	Answer
A	1 kHz above the lower band edge
B	The exact lower band edge
C	300 Hz above the lower band edge
D	3 kHz above the lower band edge

2. - E1B10

What frequencies are authorized to an amateur station operating under RACES rules?

Select	Answer
A	Specific segments in the amateur service MF, HF, VHF and UHF bands
B	Specific local government channels
C	Military Auxiliary Radio System (MARS) channels
D	All amateur service frequencies authorized to the control operator

3. - E1C10

What types of amateur stations may automatically retransmit the radio signals of other amateur stations?

Select	Answer
A	Only earth stations, repeater stations or model craft
B	Only auxiliary, beacon or space stations
C	Only auxiliary, repeater or space stations
D	Only beacon, repeater or space stations

4. - E1D04

What is an Earth station in the amateur satellite service?

Select	Answer
A	An amateur station within 50 km of the Earth's surface intended for communications with amateur stations by means of objects in space
B	An amateur station that transmits telemetry consisting of measurement of upper atmosphere
C	An amateur station that is not able to communicate using amateur satellites
D	Any amateur station on the surface of the Earth

5. - E1E01

What is the minimum number of qualified VEs required to administer an Element 4 amateur operator license examination?

Select	Answer
A	2
B	4
C	5
D	3

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. - E2A09

What do the terms L band and S band specify with regard to satellite communications?

Select	Answer
A	Which sideband to use
B	The 23 centimeter and 13 centimeter bands
C	The 2 meter and 70 centimeter bands
D	FM and Digital Store-and-Forward systems

8. - E2B04

What is blanking in a video signal?

Select	Answer
A	Transmitting a black and white test pattern
B	Turning off the scanning beam at the conclusion of a transmission
C	Turning off the scanning beam while it is traveling from right to left or from bottom to top
D	Synchronization of the horizontal and vertical sync pulses

9. - E2C08

Which of the following contacts may be confirmed through the U.S. QSL bureau system?

Select	Answer
A	Contacts using tactical call signs
B	Repeater contacts between U.S. club members
C	Contacts between a U.S. station and a non-U.S. station
D	Special event contacts between stations in the U.S.

10. - E2D08

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

Select	Answer
A	Unnumbered Information
B	Disconnect
C	Acknowledgement
D	Connect

11. - E2E01

Which type of modulation is common for data emissions below 30 MHz?

Select	Answer
A	DTMF tones modulating an FM signal
B	Spread spectrum
C	FSK
D	Pulse modulation

12. - E3A04

What do Hepburn maps predict?

Select	Answer
A	Sporadic E propagation
B	Locations of auroral reflecting zones
C	Likelihood of rain-scatter along cold or warm fronts
D	Probability of tropospheric propagation

13. - E3B07

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

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

14. - E3C13

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

Select	Answer
A	Horizontal
B	Vertical
C	Circular
D	Elliptical

15. - E4A07

Which of the following is an advantage of using an antenna analyzer compared to an SWR bridge to measure antenna SWR?

Select	Answer
A	Antenna analyzers display a time-varying representation of the modulation envelope
B	All of these choices are correct
C	Antenna analyzers automatically tune your antenna for resonance
D	Antenna analyzers do not need an external RF source

16. - E4B02

What is an advantage of using a bridge circuit to measure impedance?

Select	Answer
A	It is relatively immune to drift in the signal generator source
B	It is very precise in obtaining a signal null
C	It can display results directly in Smith chart format
D	It provides an excellent match under all conditions

17. - E4C04

How is the noise figure of a receiver defined?

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

18. - E4D06

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

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

19. - E4E15

Which of the following can cause shielded cables to radiate or receive interference?

Select	Answer
A	Common mode currents on the shield and conductors
B	Use of braided shielding material
C	Tying all ground connections to a common point resulting in differential mode currents in the shield
D	Low inductance ground connections at both ends of the shield

20. - E5A15

Which of the following can increase Q for inductors and capacitors?

Select	Answer
A	Higher self-resonant frequency
B	Lower losses
C	Lower reactance
D	Lower self-resonant frequency

21. - E5B11

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 25 ohms, R is 100 ohms, and XL is 50 ohms?

Select	Answer
A	76 degrees with the voltage leading the current
B	14 degrees with the voltage lagging the current
C	14 degrees with the voltage leading the current
D	76 degrees with the voltage lagging the current

22. - E5C12

If you plot the impedance of a circuit using the rectangular coordinate system and find the impedance point falls on the right side of the graph on the horizontal axis, what do you know about the circuit?

Select	Answer
A	It contains resistance and inductive reactance
B	It has to be a direct current circuit
C	It is equivalent to a pure resistance
D	It contains resistance and capacitive reactance

23. - E5D03

What is microstrip?

Select	Answer
A	Lightweight transmission line made of common zip cord
B	Short lengths of coax mounted on printed circuit boards to minimize time delay between microwave circuits
C	Miniature coax used for low power applications
D	Precision printed circuit conductors above a ground plane that provide constant impedance interconnects at microwave frequencies

24. - E6A12

Why do many MOSFET devices have internally connected Zener diodes on the gates?

Select	Answer
A	To provide a voltage reference for the correct amount of reverse-bias gate voltage
B	To reduce the chance of the gate insulation being punctured by static discharges or excessive voltages
C	To keep the gate voltage within specifications and prevent the device from overheating
D	To protect the substrate from excessive voltages

25. - E6B05

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

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

26. - E6C02

What happens when the level of a comparator's input signal crosses the threshold?

Select	Answer
A	The IC input can be damaged
B	The feedback loop becomes unstable
C	The comparator changes its output state
D	The comparator enters latch-up

27. - E6D01

How many turns will be required to produce a 5-microhenry inductor using a powdered-iron toroidal core that has an inductance index (A L) value of 40 microhenrys/100 turns?

Select	Answer
A	35 turns
B	13 turns
C	79 turns
D	141 turns

28. - E6E11

What is a characteristic of DIP packaging used for integrated circuits?

Select	Answer
A	Two chips in each package (Dual In Package)
B	A total of two rows of connecting pins placed on opposite sides of the package (Dual In-line Package)
C	Low leakage doubly insulated package
D	Package mounts in a direct inverted position

29. - 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 digital encryption device often used to encrypt spacecraft control signals
C	A device which detects rotation of a control by interrupting a light source with a patterned wheel
D	A device which measures the strength of a beam of light using analog to digital conversion

30. - E7A11

What type of logic defines "1" as a high voltage?

Select	Answer
A	Negative logic
B	Assertive Logic
C	Reverse Logic
D	Positive Logic

31. - E7B01

For what portion of a signal cycle does a Class AB amplifier operate?

Select	Answer
A	More than 180 degrees but less than 360 degrees
B	Less than 180 degrees
C	The entire cycle
D	Exactly 180 degrees

32. - E7C15

What is a crystal lattice filter?

Select	Answer
A	A power supply filter made with interlaced quartz crystals
B	An audio filter made with four quartz crystals that resonate at 1kHz intervals
C	A filter with wide bandwidth and shallow skirts made using quartz crystals
D	A filter with narrow bandwidth and steep skirts made using quartz crystals

33. - E7D11

What circuit element is controlled by a series analog voltage regulator to maintain a constant output voltage?

Select	Answer
A	Pass transistor
B	Reference voltage
C	Switching inductance
D	Error amplifier

34. - E7E08

What are the principal frequencies that appear at the output of a mixer circuit?

Select	Answer
A	Two and four times the original frequency
B	The two input frequencies along with their sum and difference frequencies
C	The sum, difference and square root of the input frequencies
D	1.414 and 0.707 times the input frequency

35. - E7F16

How might the sampling rate of an existing digital signal be adjusted by a factor of 3/4?

Select	Answer
A	Change the gain by a factor of 3/4
B	Multiply each sample value by a factor of 3/4
C	Add 3 to each input value and subtract 4 from each output value
D	Interpolate by a factor of three, then decimate by a factor of four

36. - E7G02

What is the effect of ringing in a filter?

Select	Answer
A	Partial cancellation of the signal over a range of frequencies
B	An echo caused by a long time delay
C	A reduction in high frequency response
D	Undesired oscillations added to the desired signal

37. - E7H09

What type of frequency synthesizer circuit uses a phase accumulator, lookup table, digital to analog converter, and a low-pass anti-alias filter?

Select	Answer
A	A phase locked loop synthesizer
B	A diode-switching matrix synthesizer
C	A hybrid synthesizer
D	A direct digital synthesizer

38. - E8A03

What type of wave does a Fourier analysis show to be made up of sine waves of a given fundamental frequency plus all of its harmonics?

Select	Answer
A	A cosine wave
B	A sawtooth wave
C	A sine wave
D	A square wave

39. - E8B01

What is the term for the ratio between the frequency deviation of an RF carrier wave and the modulating frequency of its corresponding FM-phone signal?

Select	Answer
A	Modulation index
B	Quieting index
C	FM compressibility
D	Percentage of modulation

40. - E8C04

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

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

41. - E8D03

How does the spread spectrum technique of frequency hopping work?

Select	Answer
A	If interference is detected by the receiver it will signal the transmitter to change frequencies
B	If interference is detected by the receiver it will signal the transmitter to wait until the frequency is clear
C	A pseudo-random binary bit stream is used to shift the phase of an RF carrier very rapidly in a particular sequence
D	The frequency of the transmitted signal is changed very rapidly according to a particular sequence also used by the receiving station

42. - E9A09

How is antenna efficiency calculated?

Select	Answer
A	(radiation resistance / transmission resistance) x 100 per cent
B	(radiation resistance / total resistance) x 100 per cent
C	(total resistance / radiation resistance) x 100 per cent
D	(effective radiated power / transmitter output) x 100 percent

43. - E9B04

What may occur when a directional antenna is operated at different frequencies within the band for which it was designed?

Select	Answer
A	Element spacing limits could be exceeded
B	The E-field and H-field patterns may reverse
C	Feed point impedance may become negative
D	The gain may change depending on frequency

44. - E9C12

Which of the following describes an extended double Zepp antenna?

Select	Answer
A	A wideband vertical antenna constructed from precisely tapered aluminum tubing
B	A portable antenna erected using two push support poles
C	A center fed 1.25 wavelength antenna (two 5/8 wave elements in phase)
D	An end fed folded dipole antenna

45. - E9D08

What happens as the Q of an antenna increases?

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

46. - E9E07

What term best describes the interactions at the load end of a mismatched transmission line?

Select	Answer
A	Velocity factor
B	Reflection coefficient
C	Characteristic impedance
D	Dielectric constant

47. - E9F01

What is the velocity factor of a transmission line?

Select	Answer
A	The velocity of the wave in the transmission line multiplied by the velocity of light in a vacuum
B	The velocity of the wave in the transmission line divided by the velocity of light in a vacuum
C	The ratio of the characteristic impedance of the line to the terminating impedance
D	The index of shielding for coaxial cable

48. - E9G11

How are the wavelength scales on a Smith chart calibrated?

Select	Answer
A	In fractions of transmission line electrical frequency
B	In fractions of transmission line electrical wavelength
C	In fractions of antenna electrical frequency
D	In fractions of antenna electrical wavelength

49. - E9H10

How can the output voltage of a multiple turn receiving loop antenna be increased?

Select	Answer
A	By reducing the permeability of the loop shield
B	By increasing either the number of wire turns in the loop or the area of the loop structure or both
C	By winding adjacent turns in opposing directions
D	By increasing the number of wire turns in the loop and reducing the area of the loop structure

50. - E0A08

What does SAR measure?

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