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

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1. - E1A07

Which amateur band requires transmission on specific channels rather than on a range of frequencies?

Select	Answer
A	60 meter band
B	12 meter band
C	17 meter band
D	30 meter band

2. - E1B08

What limitations may the FCC place on an amateur station if its signal causes interference to domestic broadcast reception, assuming that the receivers involved are of good engineering design?

Select	Answer
A	The amateur station must avoid transmitting during certain hours on frequencies that cause the interference
B	The amateur station must cease operation on all frequencies below 30 MHz
C	The amateur station must cease operation
D	The amateur station must cease operation on all frequencies above 30 MHz

3. - E1C02

What is meant by automatic control of a station?

Select	Answer
A	The use of devices and procedures for control so that the control operator does not have to be present at a control point
B	A station operating with its output power controlled automatically
C	The use of a control link between a control point and a locally controlled station
D	Remotely controlling a station's antenna pattern through a directional control link

4. - E1D08

Which VHF amateur service bands have frequencies available for space stations?

Select	Answer
A	2 meters and 1.25 meters
B	6 meters and 2 meters
C	2 meters
D	6 meters, 2 meters, and 1.25 meters

5. - E1E01

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

Select	Answer
A	4
B	2
C	3
D	5

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

7. - E2A14

What technology is used to track, in real time, balloons carrying amateur radio transmitters?

Select	Answer
A	Bandwidth compressed LORAN
B	Radar
C	Doppler shift of beacon signals
D	APRS

8. - E2B10

Which of the following is an acceptable bandwidth for Digital Radio Mondiale (DRM) based voice or SSTV digital transmissions made on the HF amateur bands?

Select	Answer
A	10 KHz
B	15 KHz
C	20 KHz
D	3 KHz

9. - E2C03

From which of the following bands is amateur radio contesting generally excluded?

Select	Answer
A	30 m
B	6 m
C	33 cm
D	2 m

10. - E2D12

How does JT65 improve EME communications?

Select	Answer
A	It controls the receiver to track Doppler shift
B	It supplies signals to guide the antenna to track the Moon
C	All of these choices are correct
D	It can decode signals many dB below the noise floor using FEC

11. - E2E07

What is the typical bandwidth of a properly modulated MFSK16 signal?

Select	Answer
A	2.16 kHz
B	31 Hz
C	316 Hz
D	550 Hz

12. - E3A09

Which of the following frequency range is most suited for meteor scatter communications?

Select	Answer
A	10 MHz - 14 MHz
B	220 MHz - 450 MHz
C	1.8 MHz - 1.9 MHz
D	28 MHz - 148 MHz

13. - E3B05

Which amateur bands typically support long-path propagation?

Select	Answer
A	30 meters to 10 meters
B	160 meters to 10 meters
C	6 meters to 2 meters
D	160 meters to 40 meters

14. - E3C02

What is indicated by a rising A or K index?

Select	Answer
A	An increase in the critical frequency
B	Higher levels of solar UV radiation
C	Decreasing disruption of the geomagnetic field
D	Increasing disruption of the geomagnetic field

15. - E4A09

When using a computer's soundcard input to digitize signals, what is the highest frequency signal that can be digitized without aliasing?

Select	Answer
A	It depends on how the data is stored internally
B	The same as the sample rate
C	One-half the sample rate
D	One-tenth the sample rate

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 resonant circuit
D	Short circuit, open circuit, and 50 ohms

17. - E4C16

Which of the following is caused by missing codes in an SDR receiver's analog-to-digital converter?

Select	Answer
A	Overload
B	Excess output level
C	Distortion
D	Loss of sensitivity

18. - E4D13

Which of the following can cause receiver desensitization?

Select	Answer
A	Strong adjacent channel signals
B	Audio bias adjusted too high
C	Squelch gain misadjusted
D	Audio gain adjusted too low

19. - E4E10

What is a common characteristic of interference caused by a touch controlled electrical device?

Select	Answer
A	The interfering signal may drift slowly across the HF spectrum
B	The interfering signal sounds like AC hum on an AM receiver or a carrier modulated by 60 Hz hum on a SSB or CW receiver
C	The interfering signal can be several kHz in width and usually repeats at regular intervals across a HF band
D	All of these choices are correct

20. - E5A13

What is an effect of increasing Q in a resonant circuit?

Select	Answer
A	Fewer components are needed for the same performance
B	Internal voltages and circulating currents increase
C	Phase shift can become uncontrolled
D	Parasitic effects are minimized

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

22. - E5C13

What coordinate system is often used to display the resistive, inductive, and/or capacitive reactance components of impedance?

Select	Answer
A	Maidenhead grid
B	Rectangular coordinates
C	Faraday grid
D	Elliptical coordinates

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. - E6A13

What do the initials CMOS stand for?

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

25. - E6B01

What is the most useful characteristic of a Zener diode?

Select	Answer
A	An internal capacitance that varies with the applied voltage
B	A constant current drop under conditions of varying voltage
C	A constant voltage drop under conditions of varying current
D	A negative resistance region

26. - E6C02

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

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

27. - E6D06

What core material property determines the inductance of a toroidal inductor?

Select	Answer
A	Reactivity
B	Thermal impedance
C	Permeability
D	Resistance

28. - E6E06

What characteristics of the MMIC make it a popular choice for VHF through microwave circuits?

Select	Answer
A	Controlled gain, low noise figure, and constant input and output impedance over the specified frequency range
B	Nearly infinite gain, very high input impedance, and very low output impedance
C	The ability to retrieve information from a single signal even in the presence of other strong signals
D	Plate current that is controlled by a control grid

29. - E6F03

What is the most common configuration of an optoisolator or optocoupler?

Select	Answer
A	A lens and a photomultiplier
B	An LED and a phototransistor
C	An amplitude modulated helium-neon laser
D	A frequency modulated helium-neon laser

30. - E7A06

What is a characteristic of a monostable multivibrator?

Select	Answer
A	It switches momentarily to the opposite binary state and then returns to its original state after a set time
B	It stores one bit of data in either a 0 or 1 state
C	It maintains a constant output voltage, regardless of variations in the input voltage
D	It produces a continuous square wave oscillating between 1 and 0

31. - E7B18

What is a characteristic of a grounded-grid amplifier?

Select	Answer
A	Low bandwidth
B	High filament voltage
C	Low input impedance
D	High power gain

32. - E7C03

What advantage does a Pi-L-network have over a regular Pi-network for impedance matching between the final amplifier of a vacuum-tube transmitter and an antenna?

Select	Answer
A	Greater harmonic suppression
B	Greater transformation range
C	Lower losses
D	Higher efficiency

33. - E7D03

What device is typically used as a stable reference voltage in a linear voltage regulator?

Select	Answer
A	A tunnel diode
B	A varactor diode
C	A Zener diode
D	An SCR

34. - E7E12

What is a frequency discriminator stage in a FM receiver?

Select	Answer
A	An FM generator circuit
B	An automatic band-switching circuit
C	A circuit for filtering two closely adjacent signals
D	A circuit for detecting FM signals

35. - E7F17

What do the letters I and Q in I/Q Modulation represent?

Select	Answer
A	Inactive and Quiescent
B	Instantaneous and Quenched
C	Instantaneous and Quasi-stable
D	In-phase and Quadrature

36. - E7G08

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

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

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 direct digital synthesizer
C	A hybrid synthesizer
D	A diode-switching matrix synthesizer

38. - E8A05

What would be the most accurate way of measuring the RMS voltage of a complex waveform?

Select	Answer
A	By measuring the voltage with a D'Arsonval meter
B	By measuring the heating effect in a known resistor
C	By using an absorption wave meter
D	By using a grid dip meter

39. - E8B06

What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus or minus 7.5 kHz when the maximum modulation frequency is 3.5 kHz?

Select	Answer
A	0.214
B	47
C	2.14
D	0.47

40. - E8C08

How does ARQ accomplish error correction?

Select	Answer
A	If errors are detected, a retransmission is requested
B	Special polynomial codes provide automatic correction
C	If errors are detected, redundant data is substituted
D	Special binary codes provide automatic correction

41. - E8D04

What is the primary effect of extremely short rise or fall time on a CW signal?

Select	Answer
A	More difficult to copy
B	The generation of RF harmonics
C	Limits data speed
D	The generation of key clicks

42. - E9A10

Which of the following choices is a way to improve the efficiency of a ground-mounted quarter-wave vertical antenna?

Select	Answer
A	Reduce the diameter of the radiating element
B	Shorten the radiating element
C	Install a good radial system
D	Isolate the coax shield from ground

43. - E9B07

How does the total amount of radiation emitted by a directional gain antenna compare with the total amount of radiation emitted from an 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 increased by the gain of the antenna
C	They are the same
D	The total amount of radiation from the directional antenna is stronger by its front-to-back ratio

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

45. - E9D07

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

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

46. - E9E11

What is an effective way of matching a feed line to a VHF or UHF antenna when the impedances of both the antenna and feed line are unknown?

Select	Answer
A	Use a 50 ohm 1:1 balun between the antenna and feed line
B	Connect a parallel-resonant LC network across the antenna feed terminals
C	Use the universal stub matching technique
D	Connect a series-resonant LC network across the antenna feed terminals

47. - E9F12

What impedance does a 1/4 wavelength transmission line present to a generator when the line is open at the far end?

Select	Answer
A	Very low impedance
B	The same as the input impedance to the generator
C	The same as the characteristic impedance of the line
D	Very high impedance

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 wavelength
D	In fractions of antenna electrical frequency

49. - E9H11

What characteristic of a cardioid pattern antenna is useful for direction finding?

Select	Answer
A	A very sharp single null
B	A very sharp peak
C	Broad band response
D	High-radiation angle

50. - E0A08

What does SAR measure?

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