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

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1. - E1A10

If an amateur station is installed aboard a ship or aircraft, what condition must be met before the station is operated?

Select	Answer
A	The amateur station operator must agree not to transmit when the main radio of the ship or aircraft is in use
B	The amateur station must have a power supply that is completely independent of the main ship or aircraft power supply
C	The amateur operator must have an FCC Marine or Aircraft endorsement on his or her amateur license
D	Its operation must be approved by the master of the ship or the pilot in command of the aircraft

2. - E1B09

Which amateur stations may be operated under RACES rules?

Select	Answer
A	Any FCC-licensed amateur station participating in the Military Auxiliary Radio System (MARS)
B	Only those club stations licensed to Amateur Extra class operators
C	Any FCC-licensed amateur station certified by the responsible civil defense organization for the area served
D	Any FCC-licensed amateur station except a Technician class

3. - E1C09

Which of these ranges of frequencies is available for an automatically controlled repeater operating below 30 MHz?

Select	Answer
A	24.940 MHz - 24.990 MHz
B	18.110 MHz - 18.168 MHz
C	29.500 MHz - 29.700 MHz
D	10.100 MHz - 10.150 MHz

4. - E1D03

What is a telecommand station in the amateur satellite service?

Select	Answer
A	An amateur station located on the Earth's surface for communication with other Earth stations by means of Earth satellites
B	An amateur station that transmits communications to initiate, modify or terminate functions of a space station
C	An amateur station located more than 50 km above the Earth's surface
D	An amateur station that transmits telemetry consisting of measurements of upper atmosphere

5. - E1E04

Which of the following best describes the Volunteer Examiner accreditation process?

Select	Answer
A	The amateur operator applying must pass a VE examination administered by the FCC Enforcement Bureau
B	Each General, Advanced and Amateur Extra Class operator is automatically accredited as a VE when the license is granted
C	The prospective VE obtains accreditation from the FCC
D	The procedure by which a VEC confirms that the VE applicant meets FCC requirements to serve as an examiner

6. - E1F08

Which of the following types of amateur station communications are prohibited?

Select	Answer
A	Communications that have a religious content
B	Communications that have a political content, except as allowed by the Fairness Doctrine
C	Communications in a language other than English
D	Communications transmitted for hire or material compensation, except as otherwise provided in the rules

7. - E2A14

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

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

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	3 KHz
D	20 KHz

9. - E2C03

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

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

10. - E2D03

Which of the following digital modes is especially useful for EME communications?

Select	Answer
A	PACTOR III
B	FSK441
C	Olivia
D	JT65

11. - E2E05

Which type of digital mode does not support keyboard-to-keyboard operation?

Select	Answer
A	PSK31
B	RTTY
C	MFSK
D	Winlink

12. - E3A16

Which of the following best describes electromagnetic waves traveling in free space?

Select	Answer
A	The waves are reflected by the ionosphere and return to their source
B	The energy propagates through a medium with a high refractive index
C	Electric and magnetic fields become aligned as they travel
D	Changing electric and magnetic fields propagate the energy

13. - E3B14

What happens to linearly polarized radio waves that split into ordinary and extraordinary waves in the ionosphere?

Select	Answer
A	They are bent toward the magnetic poles
B	They become phase-locked
C	Their polarization is randomly modified
D	They become elliptically polarized

14. - E3C15

What might a sudden rise in radio background noise indicate?

Select	Answer
A	Long-path propagation is occurring
B	A solar flare has occurred
C	A meteor ping
D	Increased transequatorial propagation likely

15. - E4A13

How is the compensation of an oscilloscope probe typically adjusted?

Select	Answer
A	A high frequency sine wave is displayed and the probe is adjusted for maximum amplitude
B	A DC voltage standard is displayed and the probe is adjusted until the displayed voltage is accurate
C	A frequency standard is displayed and the probe is adjusted until the deflection time is accurate
D	A square wave is displayed and the probe is adjusted until the horizontal portions of the displayed wave are as nearly flat as possible

16. - E4B05

If a frequency counter with a specified accuracy of +/- 10 ppm reads 146,520,000 Hz, what is the most the actual frequency being measured could differ from the reading?

Select	Answer
A	1465.20 Hz
B	146.52 Hz
C	146.52 kHz
D	10 Hz

17. - E4C11

Which of the following is a desirable amount of selectivity for an amateur SSB phone receiver?

Select	Answer
A	2.4 kHz
B	4.8 kHz
C	1 kHz
D	4.2 kHz

18. - E4D10

What does a third-order intercept level of 40 dBm mean with respect to receiver performance?

Select	Answer
A	The receiver can tolerate signals up to 40 dB above the noise floor without producing third-order intermodulation products
B	Signals less than 40 dBm will not generate audible third-order intermodulation products
C	A pair of 40 dBm signals will theoretically generate a third-order intermodulation product with the same level as the input signals
D	A pair of 1 mW input signals will produce a third-order intermodulation product which is 40 dB stronger than the input signal

19. - E4E01

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

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

20. - E5A04

What is the magnitude of the impedance of a circuit with a resistor, an inductor and a capacitor all in parallel, at resonance?

Select	Answer
A	Low, as compared to the circuit resistance
B	Approximately equal to inductive reactance
C	Approximately equal to capacitive reactance
D	Approximately equal to circuit resistance

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

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

23. - E5D03

What is microstrip?

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

24. - E6A03

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

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

25. - E6B05

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

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

26. - E6C07

What best describes a pull-up or pull-down resistor?

Select	Answer
A	A resistor that insures that an oscillator frequency does not drive lower over time
B	A resistor in a keying circuit used to reduce key clicks
C	A resistor connected to an op-amp output that only functions when the logic output is false
D	A resistor connected to the positive or negative supply line used to establish a voltage when an input or output is an open circuit

27. - E6D05

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

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

28. - E6E03

Which of the following materials is likely to provide the highest frequency of operation when used in MMICs?

Select	Answer
A	Silicon dioxide
B	Silicon nitride
C	Gallium nitride
D	Silicon

29. - E6F08

Why are optoisolators often used in conjunction with solid state circuits when switching 120VAC?

Select	Answer
A	Optoisolators provide impedance matching between the control circuit and power circuit
B	Optoisolators eliminate the effects of reflected light in the control circuit
C	Optoisolators provide a low impedance link between a control circuit and a power circuit
D	Optoisolators provide a very high degree of electrical isolation between a control circuit and the circuit being switched

30. - E7A12

What type of logic defines "0" as a high voltage?

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

31. - E7B06

Which of the following amplifier types reduces or eliminates even order harmonics?

Select	Answer
A	Class AB
B	Push-push
C	Class C
D	Push-pull

32. - E7C11

Which of the following is the common name for a filter network which is equivalent to two L-networks connected back-to-back with the two inductors in series and the capacitors in shunt at the input and output?

Select	Answer
A	Pi-L
B	Cascode
C	Pi
D	Omega

33. - E7D13

What is the equation for calculating power dissipation by a series connected linear voltage regulator?

Select	Answer
A	Input voltage divided by output current
B	Output voltage multiplied by output current
C	Input voltage multiplied by input current
D	Voltage difference from input to output multiplied by output current

34. - E7E05

What circuit is added to an FM transmitter to boost the higher audio frequencies?

Select	Answer
A	A heterodyne suppressor
B	A pre-emphasis network
C	A de-emphasis network
D	An audio prescaler

35. - E7F16

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

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

36. - E7G02

What is the effect of ringing in a filter?

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

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

38. - E8A01

What is the name of the process that shows that a square wave is made up of a sine wave plus all of its odd harmonics?

Select	Answer
A	Fourier analysis
B	Differential analysis
C	Numerical analysis
D	Vector analysis

39. - E8B10

What describes frequency division multiplexing?

Select	Answer
A	Two or more information streams are merged into a baseband, which then modulates the transmitter
B	The transmitted signal is divided into packets of information
C	The transmitted signal jumps from band to band at a predetermined rate
D	Two or more information streams are merged into a digital combiner, which then pulse position modulates the transmitter

40. - E8C07

What is the necessary bandwidth of a 4800-Hz frequency shift, 9600-baud ASCII FM transmission?

Select	Answer
A	9.6 kHz
B	4.8 kHz
C	5.76 kHz
D	15.36 kHz

41. - E8D01

Why are received spread spectrum signals resistant to interference?

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

42. - E9A18

What term describes station output, taking into account all gains and losses?

Select	Answer
A	Power factor
B	Apparent power
C	Effective radiated power
D	Half-power bandwidth

43. - E9B13

What does the abbreviation NEC stand for when applied to antenna modeling programs?

Select	Answer
A	Numerical Electromagnetic Code
B	National Electrical Code
C	Next Element Comparison
D	Numeric Electrical Computation

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

45. - E9D06

What happens to the bandwidth of an antenna as it is shortened through the use of loading coils?

Select	Answer
A	It is decreased
B	It is increased
C	No change occurs
D	It becomes flat

46. - E9E06

What is the equivalent lumped-constant network for a hairpin matching system of a 3-element Yagi?

Select	Answer
A	Pi-L-network
B	A shunt inductor
C	A series capacitor
D	Pi-network

47. - E9F08

What is the term for the ratio of the actual speed at which a signal travels through a transmission line to the speed of light in a vacuum?

Select	Answer
A	Characteristic impedance
B	Velocity factor
C	Surge impedance
D	Standing wave ratio

48. - E9G09

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

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

49. - E9H07

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

Select	Answer
A	It reduces loss of received signals caused by antenna pattern nulls, thereby increasing sensitivity
B	It compensates for the effects of an isotropic antenna, thereby improving directivity
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	Only commercial transmitters
B	Only the most powerful transmitter
C	Each transmitter operating with a duty-cycle greater than 50 percent
D	Each transmitter that produces 5 percent or more of its MPE limit at accessible locations