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

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1. - E1A08

If a station in a message forwarding system inadvertently forwards a message that is in violation of FCC rules, who is primarily accountable for the rules violation?

Select	Answer
A	The control operator of the packet bulletin board station
B	The control operators of all the stations in the system not authenticating the source from which they accept communications
C	The control operator of the originating station
D	The control operators of all the stations in the system

2. - E1B07

What is the highest modulation index permitted at the highest modulation frequency for angle modulation below 29.0 MHz?

Select	Answer
A	3.0
B	0.5
C	1.0
D	2.0

3. - E1C04

What is meant by IARP?

Select	Answer
A	The internal amateur radio practices policy of the FCC
B	An indication of increased antenna reflected power
C	An international amateur radio permit that allows U.S. amateurs to operate in certain countries of the Americas
D	A forecast of intermittent aurora radio propagation

4. - E1D08

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

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

5. - E1E05

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

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

6. - E1F01

On what frequencies are spread spectrum transmissions permitted?

Select	Answer
A	Only on amateur frequencies above 420 MHz
B	Only on amateur frequencies above 222 MHz
C	Only on amateur frequencies above 144 MHz
D	Only on amateur frequencies above 50 MHz

7. - E2A14

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

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

8. - E2B08

Which of the following is a common method of transmitting accompanying audio with amateur fast-scan television?

Select	Answer
A	All of these choices are correct
B	Frequency modulation of the video carrier
C	Frequency-modulated sub-carrier
D	A separate VHF or UHF audio link

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

10. - E2D07

What digital protocol is used by APRS?

Select	Answer
A	PACTOR
B	AX.25
C	AMTOR
D	802.11

11. - E2E07

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

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

12. - E3A11

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

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

13. - E3B12

What is the primary characteristic of chordal hop propagation?

Select	Answer
A	Propagation away from the great circle bearing between stations
B	Propagation across the geomagnetic equator
C	Signals reflected back toward the transmitting station
D	Successive ionospheric reflections without an intermediate reflection from the ground

14. - E3C15

What might a sudden rise in radio background noise indicate?

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

15. - E4A14

What is the purpose of the prescaler function on a frequency counter?

Select	Answer
A	It multiplies a higher frequency signal so a low-frequency counter can display the operating frequency
B	It prevents oscillation in a low-frequency counter circuit
C	It divides a higher frequency signal so a low-frequency counter can display the input frequency
D	It amplifies low level signals for more accurate counting

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. - E4C16

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

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

18. - E4D10

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

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

19. - E4E02

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

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

20. - E5A14

What is the resonant frequency of a series RLC circuit if R is 22 ohms, L is 50 microhenrys and C is 40 picofarads?

Select	Answer
A	3.56 MHz
B	22.36 MHz
C	44.72 MHz
D	1.78 MHz

21. - E5B04

What is the time constant of a circuit having two 220 microfarad capacitors and two 1 megohm resistors, all in parallel?

Select	Answer
A	110 seconds
B	440 seconds
C	220 seconds
D	55 seconds

22. - E5C15

Which point in Figure E5-2 best represents the impedance of a series circuit consisting of a 300 ohm resistor and an 18 microhenry inductor at 3.505 MHz?

Select	Answer
A	Point 1
B	Point 7
C	Point 3
D	Point 8

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	0.866
C	0.5
D	1.414

24. - E6A12

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

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

25. - E6B09

What is a common use for point contact diodes?

Select	Answer
A	As a constant voltage source
B	As an RF detector
C	As a high voltage rectifier
D	As a constant current source

26. - E6C01

What is the function of hysteresis in a comparator?

Select	Answer
A	To prevent input noise from causing unstable output signals
B	To increase the sensitivity
C	To cause the output to change states continually
D	To allow the comparator to be used with AC input signal

27. - E6D11

How many turns will be required to produce a 1-mH inductor using a core that has an inductance index (A L) value of 523 millihenrys/1000 turns?

Select	Answer
A	229 turns
B	2 turns
C	43 turns
D	4 turns

28. - E6E10

What is the packaging technique in which leadless components are soldered directly to circuit boards?

Select	Answer
A	Virtual lead mounting
B	Stripped lead
C	Direct soldering
D	Surface mount

29. - E6F12

What absorbs the energy from light falling on a photovoltaic cell?

Select	Answer
A	Photons
B	Protons
C	Electrons
D	Holes

30. - E7A07

What logical operation does a NAND gate perform?

Select	Answer
A	It produces logic "1" at its output only when all inputs are logic "1"
B	It produces logic "0" at its output if some but not all inputs are logic "1"
C	It produces logic "0" at its output only when all inputs are logic "1"
D	It produces logic "0" at its output only when all inputs are logic "0"

31. - E7B07

Which of the following is a likely result when a Class C amplifier is used to amplify a single-sideband phone signal?

Select	Answer
A	Increased overall intelligibility
B	Signal distortion and excessive bandwidth
C	Signal inversion
D	Reduced intermodulation products

32. - E7C01

How are the capacitors and inductors of a low-pass filter Pi-network arranged between the network's input and output?

Select	Answer
A	An inductor is connected between the input and ground, another inductor is connected between the output and ground, and a capacitor is connected between the input and output
B	Two inductors are in series between the input and output, and a capacitor is connected between the two inductors and ground
C	A capacitor is connected between the input and ground, another capacitor is connected between the output and ground, and an inductor is connected between input and output
D	Two capacitors are in series between the input and output, and an inductor is connected between the two capacitors and ground

33. - E7D06

What is the purpose of Q1 in the circuit shown in Figure E7-3?

Select	Answer
A	It provides a constant load for the voltage source
B	It increases the current-handling capability of the regulator
C	It provides negative feedback to improve regulation
D	It provides D1 with current

34. - E7E01

Which of the following can be used to generate FM phone emissions?

Select	Answer
A	A balanced modulator on the audio amplifier
B	A balanced modulator on the oscillator
C	A reactance modulator on the final amplifier
D	A reactance modulator on the oscillator

35. - E7F13

What is the function of taps in a digital signal processing filter?

Select	Answer
A	Provide access for debugging software
B	Select the point at which baseband signals are generated
C	Provide incremental signal delays for filter algorithms
D	To reduce excess signal pressure levels

36. - E7G08

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

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

37. - E7H06

Which of the following oscillator circuits are commonly used in VFOs?

Select	Answer
A	Armstrong and deForest
B	Colpitts and Hartley
C	Negative feedback and balanced feedback
D	Pierce and Zener

38. - E8A05

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

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

39. - E8B08

What describes Orthogonal Frequency Division Multiplexing?

Select	Answer
A	A digital mode for narrow band, slow speed transmissions
B	A digital modulation technique using subcarriers at frequencies chosen to avoid intersymbol interference
C	A frequency modulation technique which uses non-harmonically related frequencies
D	A bandwidth compression technique using Fourier transforms

40. - E8C09

Which is the name of a digital code where each preceding or following character changes by only one bit?

Select	Answer
A	Binary Coded Decimal Code
B	Gray code
C	Excess 3 code
D	Extended Binary Coded Decimal Interchange Code

41. - E8D07

What is a common cause of overmodulation of AFSK signals?

Select	Answer
A	Excessive numbers of retries
B	Ground loops
C	Excessive transmit audio levels
D	Bit errors in the modem

42. - E9A09

How is antenna efficiency calculated?

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

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	All of these choices are correct
C	Polar plots of the far field elevation and azimuth patterns
D	Antenna gain

44. - E9C13

What is the main effect of placing a vertical antenna over an imperfect ground?

Select	Answer
A	It reduces losses in the radiating portion of the antenna
B	It changes the impedance angle of the matching network
C	It causes increased SWR
D	It reduces low-angle radiation

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

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. - E9F06

What is the approximate physical length of an air-insulated, parallel conductor transmission line that is electrically one-half wavelength long at 14.10 MHz?

Select	Answer
A	10 meters
B	15 meters
C	71 meters
D	20 meters

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. - E9H04

What is an advantage of using a shielded loop antenna for direction finding?

Select	Answer
A	It is electro statically balanced against ground, giving better nulls
B	It automatically cancels ignition noise in mobile installations
C	It allows stations to communicate without giving away their position
D	It eliminates tracking errors caused by strong out-of-band signals

50. - E0A05

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

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

Figure E5-2

Figure E7-3