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

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1. - E1A09

What is the first action you should take if your digital message forwarding station inadvertently forwards a communication that violates FCC rules?

Select	Answer
A	Notify the originating station that the communication does not comply with FCC rules
B	Discontinue forwarding all messages
C	Discontinue forwarding the communication as soon as you become aware of it
D	Notify the nearest FCC Field Engineer's office

2. - E1B03

Within what distance must an amateur station protect an FCC monitoring facility from harmful interference?

Select	Answer
A	1 mile
B	30 miles
C	10 miles
D	3 miles

3. - E1C02

What is meant by automatic control of a station?

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

4. - E1D05

What class of licensee is authorized to be the control operator of a space station?

Select	Answer
A	Only General, Advanced or Amateur Extra Class
B	All except Technician Class
C	Only Amateur Extra Class
D	Any class with appropriate operator privileges

5. - E1E05

What is the minimum passing score on amateur operator license examinations?

Select	Answer
A	Minimum passing score of 77%
B	Minimum passing score of 80%
C	Minimum passing score of 70%
D	Minimum passing score of 74%

6. - E1F07

When may an amateur station send a message to a business?

Select	Answer
A	When transmitting international third-party communications
B	When the total money involved does not exceed $25
C	When neither the amateur nor his or her employer has a pecuniary interest in the communications
D	When the control operator is employed by the FCC or another government agency

7. - E2A11

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

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

8. - E2B16

Which is a video standard used by North American Fast Scan ATV stations?

Select	Answer
A	NTSC
B	Scottie
C	PAL
D	DRM

9. - E2C12

What might help to restore contact when DX signals become too weak to copy across an entire HF band a few hours after sunset?

Select	Answer
A	Switch to a lower frequency HF band
B	Wait 24 hours before attempting another communication on the band
C	Wait 90 minutes or so for the signal degradation to pass
D	Switch to a higher frequency HF band

10. - E2D11

Which of the following data are used by the APRS network to communicate your location?

Select	Answer
A	Radio direction finding spectrum analysis
B	Polar coordinates
C	Latitude and longitude
D	Time and frequency

11. - E2E02

What do the letters FEC mean as they relate to digital operation?

Select	Answer
A	First Error Correction
B	Final Error Correction
C	Fatal Error Correction
D	Forward Error Correction

12. - E3A11

What is a typical range for tropospheric propagation of microwave signals?

Select	Answer
A	2500 miles
B	1200 miles
C	10 miles to 50 miles
D	100 miles to 300 miles

13. - E3B08

What type of HF propagation is probably occurring if radio signals travel along the terminator between daylight and darkness?

Select	Answer
A	Long-path
B	Sporadic-E
C	Transequatorial
D	Gray-line

14. - E3C13

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

Select	Answer
A	Elliptical
B	Circular
C	Vertical
D	Horizontal

15. - E4A03

Which of the following test instrument is used to display spurious signals and/or intermodulation distortion products in an SSB transmitter?

Select	Answer
A	A logic analyzer
B	A spectrum analyzer
C	A wattmeter
D	A time-domain reflectometer

16. - E4B03

If a frequency counter with a specified accuracy of +/- 1.0 ppm reads 146,520,000 Hz, what is the most the actual frequency being measured could differ from the reading?

Select	Answer
A	1.4652 MHz
B	14.652 kHz
C	146.52 Hz
D	165.2 Hz

17. - E4C05

What does a value of -174 dBm/Hz represent with regard to the noise floor of a receiver?

Select	Answer
A	The noise figure of a 1 Hz bandwidth receiver
B	The galactic noise contribution to minimum detectable signal
C	The minimum detectable signal as a function of receive frequency
D	The theoretical noise at the input of a perfect receiver at room temperature

18. - E4D14

Which of the following is a way to reduce the likelihood of receiver desensitization?

Select	Answer
A	Decrease the RF bandwidth of the receiver
B	Increase the receiver front end gain
C	Raise the receiver IF frequency
D	Switch from fast AGC to slow AGC

19. - E4E06

What is a major cause of atmospheric static?

Select	Answer
A	Solar radio frequency emissions
B	Geomagnetic storms
C	Thunderstorms
D	Meteor showers

20. - E5A16

What is the resonant frequency of a parallel RLC circuit if R is 33 ohms, L is 50 microhenrys and C is 10 picofarads?

Select	Answer
A	7.12 MHz
B	23.5 kHz
C	7.12 kHz
D	23.5 MHz

21. - E5B05

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

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

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	Maidenhead grid
B	Elliptical coordinates
C	Polar coordinates
D	Faraday grid

23. - E5D11

What is the power factor of an R-L circuit having a 60 degree phase angle between the voltage and the current?

Select	Answer
A	1.73
B	1.414
C	0.5
D	0.866

24. - E6A14

How does DC input impedance at the gate of a field-effect transistor compare with the DC input impedance of a bipolar transistor?

Select	Answer
A	An FET has low input impedance; a bipolar transistor has high input impedance
B	They are both low impedance
C	They are both high impedance
D	An FET has high input impedance; a bipolar transistor has low input impedance

25. - E6B08

Which of the following describes a type of semiconductor diode?

Select	Answer
A	Metal-semiconductor junction
B	Electrolytic rectifier
C	CMOS-field effect
D	Thermionic emission diode

26. - E6C10

In Figure E6-5, what is the schematic symbol for a NOR gate?

Select	Answer
A	1
B	4
C	2
D	3

27. - E6D04

Which materials are commonly used as a slug core in a variable inductor?

Select	Answer
A	Polystyrene and polyethylene
B	Cobalt and aluminum
C	Teflon and Delrin
D	Ferrite and brass

28. - E6E04

Which is the most common input and output impedance of circuits that use MMICs?

Select	Answer
A	300 ohms
B	10 ohms
C	50 ohms
D	450 ohms

29. - E6F08

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

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

30. - E7A01

Which is a bi-stable circuit?

Select	Answer
A	A flip-flop
B	A clock
C	An "AND" gate
D	An "OR" gate

31. - E7B13

In Figure E7-2, what is the purpose of R?

Select	Answer
A	Fixed bias
B	Voltage regulation
C	Collector load
D	Emitter load

32. - E7C13

What is one advantage of a Pi-matching network over an L-matching network consisting of a single inductor and a single capacitor?

Select	Answer
A	Pi-networks have fewer components
B	Pi-networks are designed for balanced input and output
C	The Q of Pi-networks can be varied depending on the component values chosen
D	L-networks cannot perform impedance transformation

33. - E7D01

What is one characteristic of a linear electronic voltage regulator?

Select	Answer
A	It has a ramp voltage as its output
B	It eliminates the need for a pass transistor
C	The control element duty cycle is proportional to the line or load conditions
D	The conduction of a control element is varied to maintain a constant output voltage

34. - E7E03

How does an analog phase modulator function?

Select	Answer
A	By varying the tuning of a microphone preamplifier to produce AM signals
B	By varying the tuning of a microphone preamplifier to produce PM signals
C	By varying the tuning of an amplifier tank circuit to produce AM signals
D	By varying the tuning of an amplifier tank circuit to produce PM signals

35. - E7F15

Which of the following is an advantage of a Finite Impulse Response (FIR) filter vs an Infinite Impulse Response (IIR) digital filter?

Select	Answer
A	FIR filters can respond faster to impulses
B	FIR filters are easier to implement for a given set of passband rolloff requirements
C	All of these choices are correct
D	FIR filters delay all frequency components of the signal by the same amount

36. - E7G01

What is the typical output impedance of an integrated circuit op-amp?

Select	Answer
A	Very low
B	Very high
C	100 ohms
D	1000 ohms

37. - E7H07

How can an oscillator's microphonic responses be reduced?

Select	Answer
A	Use of NP0 capacitors
B	Using the oscillator only for CW and digital signals
C	Eliminating noise on the oscillator's power supply
D	Mechanically isolating the oscillator circuitry from its enclosure

38. - E8A08

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

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

39. - E8B09

What is meant by deviation ratio?

Select	Answer
A	The ratio of the highest audio modulating frequency to the average audio modulating frequency
B	The ratio of the carrier center frequency to the audio modulating frequency
C	The ratio of the audio modulating frequency to the center carrier frequency
D	The ratio of the maximum carrier frequency deviation to the highest audio modulating frequency

40. - E8C10

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

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

41. - E8D04

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

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

42. - E9A17

What is the effective radiated power of a repeater station with 200 watts transmitter power output, 2 dB feed line loss, 2.8 dB duplexer loss, 1.2 dB circulator loss, and 7 dBi antenna gain?

Select	Answer
A	63.2 watts
B	252 watts
C	632 watts
D	159 watts

43. - E9B06

What is the elevation angle of peak response in the antenna radiation pattern shown in Figure E9-2?

Select	Answer
A	25 degrees
B	7.5 degrees
C	75 degrees
D	45 degrees

44. - E9C01

What is the radiation pattern of two 1/4-wavelength vertical antennas spaced 1/2-wavelength apart and fed 180 degrees out of phase?

Select	Answer
A	Omni-directional
B	A figure-8 oriented along the axis of the array
C	A figure-8 broadside to the axis of the array
D	Cardioid

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

46. - E9E08

Which of the following measurements is characteristic of a mismatched transmission line?

Select	Answer
A	An SWR less than 1:1
B	A reflection coefficient greater than 1
C	A dielectric constant greater than 1
D	An SWR greater than 1:1

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

48. - E9G05

What type of chart is shown in Figure E9-3?

Select	Answer
A	Free space radiation directivity chart
B	Azimuth angle radiation pattern chart
C	Elevation angle radiation pattern chart
D	Smith chart

49. - E9H07

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

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

50. - E0A05

What is one of the potential hazards of using microwaves in the amateur radio bands?

Select	Answer
A	The high gain antennas commonly used can result in high exposure levels
B	Microwaves often travel long distances by ionospheric reflection
C	The extremely high frequency energy can damage the joints of antenna structures
D	Microwaves are ionizing radiation

Figure E6-5

Figure E7-2

Figure E9-2

Figure E9-3