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

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1. - E1A04

With your transceiver displaying the carrier frequency of phone signals, you hear a DX station calling CQ on 3.601 MHz LSB. Is it legal to return the call using lower sideband on the same frequency?

Select	Answer
A	No, U.S. stations are not permitted to use phone emissions below 3.610 MHz
B	Yes, because the DX station initiated the contact
C	Yes, because the displayed frequency is within the 75 meter phone band segment
D	No, the sideband will extend beyond the edge of the phone band segment

2. - E1B03

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

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

3. - E1C12

What types of communications may be transmitted to amateur stations in foreign countries?

Select	Answer
A	Communications incidental to the purpose of the amateur service and remarks of a personal nature
B	All of these choices are correct
C	Messages intended for connection to users of the maritime satellite service
D	Business-related messages for non-profit organizations

4. - E1D01

What is the definition of the term telemetry?

Select	Answer
A	One-way transmission that initiates, modifies, or terminates the functions of a device at a distance
B	One-way transmission of measurements at a distance from the measuring instrument
C	Two-way radiotelephone transmissions in excess of 1000 feet
D	Two-way single channel transmissions of data

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 74%
C	Minimum passing score of 70%
D	Minimum passing score of 80%

6. - E1F03

Under what circumstances may a dealer sell an external RF power amplifier capable of operation below 144 MHz if it has not been granted FCC certification?

Select	Answer
A	It was imported from a manufacturer in a country that does not require certification of RF power amplifiers
B	It was purchased in used condition from an amateur operator and is sold to another amateur operator for use at that operator's station
C	The equipment dealer assembled it from a kit
D	It was imported from a manufacturer in another country and was certificated by that country's government

7. - E2A10

Why may the received signal from an amateur satellite exhibit a rapidly repeating fading effect?

Select	Answer
A	Because of the Doppler Effect
B	Because of the satellite's low orbital altitude
C	Because of ionospheric absorption
D	Because the satellite is spinning

8. - E2B14

What aspect of an amateur slow-scan television signal encodes the brightness of the picture?

Select	Answer
A	Sync amplitude
B	Tone amplitude
C	Sync frequency
D	Tone frequency

9. - E2C03

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

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

10. - E2D10

How can an APRS station be used to help support a public service communications activity?

Select	Answer
A	An APRS station with a GPS unit can automatically transmit information to show a mobile station's position during the event
B	APRS stations with General Personnel Scanners can automatically relay the participant numbers and time as they pass the check points
C	All of these choices are correct
D	An APRS station with an emergency medical technician can automatically transmit medical data to the nearest hospital

11. - E2E10

Which of these digital modes has the narrowest bandwidth?

Select	Answer
A	170 Hz shift, 45 baud RTTY
B	PSK31
C	300-baud packet
D	MFSK16

12. - E3A11

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

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

13. - E3B06

Which of the following amateur bands most frequently provides long-path propagation?

Select	Answer
A	10 meters
B	80 meters
C	20 meters
D	6 meters

14. - E3C13

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

Select	Answer
A	Circular
B	Elliptical
C	Vertical
D	Horizontal

15. - E4A15

What is an advantage of a period-measuring frequency counter over a direct-count type?

Select	Answer
A	It does not require an expensive high-precision time base
B	It can run on battery power for remote measurements
C	It provides improved resolution of low-frequency signals within a comparable time period
D	It can directly measure the modulation index of an FM transmitter

16. - E4B04

If a frequency counter with a specified accuracy of +/- 0.1 ppm reads 146,520,000 Hz, what is the most the actual frequency being measured could differ from the reading?

Select	Answer
A	14.652 Hz
B	1.4652 Hz
C	0.1 MHz
D	1.4652 kHz

17. - E4C08

An SDR receiver is overloaded when input signals exceed what level?

Select	Answer
A	The maximum count value of the analog-to-digital converter
B	One-half the maximum sample rate
C	One-half the maximum sampling buffer size
D	The reference voltage of the analog-to-digital converter

18. - E4D11

Why are third-order intermodulation products created within a receiver of particular interest compared to other products?

Select	Answer
A	Third-order products are an indication of poor image rejection
B	Third-order intermodulation produces three products for every input signal within the band of interest
C	The third-order product of two signals which are in the band of interest is also likely to be within the band
D	The third-order intercept is much higher than other orders

19. - E4E12

What is one disadvantage of using some types of automatic DSP notch-filters when attempting to copy CW signals?

Select	Answer
A	Any nearby signal passing through the DSP system will overwhelm the desired signal
B	Received CW signals will appear to be modulated at the DSP clock frequency
C	A DSP filter can remove the desired signal at the same time as it removes interfering signals
D	Ringing in the DSP filter will completely remove the spaces between the CW characters

20. - E5A11

What is the half-power bandwidth of a parallel resonant circuit that has a resonant frequency of 7.1 MHz and a Q of 150?

Select	Answer
A	23.67 kHz
B	157.8 Hz
C	315.6 Hz
D	47.3 kHz

21. - E5B05

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

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

22. - E5C14

Which point on Figure E5-2 best represents the impedance of a series circuit consisting of a 400 ohm resistor and a 38 picofarad capacitor at 14 MHz?

Select	Answer
A	Point 6
B	Point 4
C	Point 2
D	Point 5

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	0.866
B	1.414
C	1.73
D	0.5

24. - E6A12

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

Select	Answer
A	To protect the substrate from excessive voltages
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 keep the gate voltage within specifications and prevent the device from overheating

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 voltage drop under conditions of varying current
C	A constant current drop under conditions of varying voltage
D	A negative resistance region

26. - E6C05

What is an advantage of CMOS logic devices over TTL devices?

Select	Answer
A	Lower power consumption
B	Lower distortion
C	Differential output capability
D	Immune to damage from static discharge

27. - E6D16

What is the common name for a capacitor connected across a transformer secondary that is used to absorb transient voltage spikes?

Select	Answer
A	Clipper capacitor
B	Trimmer capacitor
C	Snubber capacitor
D	Feedback capacitor

28. - E6E11

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

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

29. - E6F02

What happens to the conductivity of a photoconductive material when light shines on it?

Select	Answer
A	It decreases
B	It stays the same
C	It becomes unstable
D	It increases

30. - E7A01

Which is a bi-stable circuit?

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

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	Reduced intermodulation products
D	Signal inversion

32. - E7C02

Which of the following is a property of a T-network with series capacitors and a parallel shunt inductor?

Select	Answer
A	It is a high-pass filter
B	It is a band-pass filter
C	It is a notch filter
D	It is a low-pass filter

33. - E7D01

What is one characteristic of a linear electronic voltage regulator?

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

34. - E7E04

What is one way a single-sideband phone signal can be generated?

Select	Answer
A	By driving a product detector with a DSB signal
B	By using a loop modulator followed by a mixer
C	By using a reactance modulator followed by a mixer
D	By using a balanced modulator followed by a filter

35. - E7F13

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

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

36. - E7G07

What magnitude of voltage gain can be expected from the circuit in Figure E7-4 when R1 is 10 ohms and RF is 470 ohms?

Select	Answer
A	94
B	47
C	24
D	0.21

37. - E7H08

Which of the following components can be used to reduce thermal drift in crystal oscillators?

Select	Answer
A	Wirewound resistors
B	Non-inductive resistors
C	Toroidal inductors
D	NP0 capacitors

38. - E8A09

How many levels can an analog-to-digital converter with 8 bit resolution encode?

Select	Answer
A	8 multiplied by the gain of the input amplifier
B	256 divided by the gain of the input amplifier
C	256
D	8

39. - E8B02

How does the modulation index of a phase-modulated emission vary with RF carrier frequency (the modulated frequency)?

Select	Answer
A	It decreases as the RF carrier frequency increases
B	It varies with the square root of the RF carrier frequency
C	It does not depend on the RF carrier frequency
D	It increases as the RF carrier frequency increases

40. - E8C03

When performing phase shift keying, why is it advantageous to shift phase precisely at the zero crossing of the RF carrier?

Select	Answer
A	It improves carrier suppression
B	This results in the least possible transmitted bandwidth for the particular mode
C	All of these choices are correct
D	It is easier to demodulate with a conventional, non-synchronous detector

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	More difficult to copy
C	The generation of RF harmonics
D	Limits data speed

42. - E9A04

Which of the following factors may affect the feed point impedance of an antenna?

Select	Answer
A	Antenna height, conductor length/diameter ratio and location of nearby conductive objects
B	The settings of an antenna tuner at the transmitter
C	Sunspot activity and time of day
D	Transmission-line length

43. - E9B05

What type of antenna pattern over real ground is shown in Figure E9-2?

Select	Answer
A	Radiation resistance
B	Azimuth
C	Polarization
D	Elevation

44. - E9C13

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

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

45. - E9D05

What is a disadvantage of using a multiband trapped antenna?

Select	Answer
A	It might radiate harmonics
B	It is too sharply directional at lower frequencies
C	It must be neutralized
D	It radiates the harmonics and fundamental equally well

46. - E9E13

What is a use for a Wilkinson divider?

Select	Answer
A	It is used to feed low-impedance loads from a high-impedance source
B	It is used to feed high-impedance antennas from a low-impedance source
C	It is used to divide power equally between two 50 ohm loads while maintaining 50 ohm input impedance
D	It divides the operating frequency of a transmitter signal so it can be used on a lower frequency band

47. - E9F03

Why is the physical length of a coaxial cable transmission line shorter than its electrical length?

Select	Answer
A	The characteristic impedance is higher in a parallel feed line
B	The surge 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. - E9G03

Which of the following is often determined using a Smith chart?

Select	Answer
A	Satellite azimuth and elevation bearings
B	Trigonometric functions
C	Impedance and SWR values in transmission lines
D	Beam headings and radiation patterns

49. - E9H06

What is the triangulation method of direction finding?

Select	Answer
A	The geometric angles of sky waves from the source are used to determine its position
B	A fixed receiving station uses three different antennas to plot the location of the signal source
C	A fixed receiving station plots three headings to the signal source
D	Antenna headings from several different receiving locations are used to locate the signal source

50. - E0A10

What toxic material may be present in some electronic components such as high voltage capacitors and transformers?

Select	Answer
A	Polyethylene
B	Polychlorinated Biphenyls
C	Polytetrafluroethylene
D	Polymorphic silicon

Figure E5-2

Figure E7-4

Figure E9-2