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

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1. - E1A14

What is the maximum bandwidth for a data emission on 60 meters?

Select	Answer
A	60 Hz
B	170 Hz
C	2.8 kHz
D	1.5 kHz

2. - E1B04

What must be done before placing an amateur station within an officially designated wilderness area or wildlife preserve, or an area listed in the National Register of Historical Places?

Select	Answer
A	A form FSD-15 must be submitted to the Department of the Interior
B	A letter of intent must be filed with the National Audubon Society
C	A proposal must be submitted to the National Park Service
D	An Environmental Assessment must be submitted to the FCC

3. - E1C11

Which of the following operating arrangements allows an FCC-licensed U.S. citizen to operate in many European countries, and alien amateurs from many European countries to operate in the U.S.?

Select	Answer
A	ITU reciprocal license
B	All of these choices are correct
C	IARP agreement
D	CEPT agreement

4. - E1D09

Which UHF amateur service bands have frequencies available for a space station?

Select	Answer
A	70 cm only
B	33 cm and 13 cm
C	70 cm and 33 cm
D	70 cm and 13 cm

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. - 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	It was imported from a manufacturer in another country and was certificated by that country's government
D	The equipment dealer assembled it from a kit

7. - E2A07

Which of the following types of signals can be relayed through a linear transponder?

Select	Answer
A	All of these choices are correct
B	PSK and Packet
C	SSB and SSTV
D	FM and CW

8. - E2B14

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

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

9. - E2C05

What is the function of a DX QSL Manager?

Select	Answer
A	To allocate frequencies for DXpeditions
B	To run a net to allow many stations to contact a rare DX station
C	To relay calls to and from a DX station
D	To handle the receiving and sending of confirmation cards for a DX station

10. - E2D12

How does JT65 improve EME communications?

Select	Answer
A	All of these choices are correct
B	It supplies signals to guide the antenna to track the Moon
C	It controls the receiver to track Doppler shift
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	31 Hz
B	550 Hz
C	2.16 kHz
D	316 Hz

12. - E3A07

Atmospheric ducts capable of propagating microwave signals often form over what geographic feature?

Select	Answer
A	Forests
B	Urban areas
C	Mountain ranges
D	Bodies of water

13. - E3B01

What is transequatorial propagation?

Select	Answer
A	Propagation between two mid-latitude points at approximately the same distance north and south of the magnetic equator
B	Propagation between two continents by way of ducts along the magnetic equator
C	Propagation between any two points located on the magnetic equator
D	Propagation between two stations at the same latitude

14. - E3C02

What is indicated by a rising A or K index?

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

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

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	146.52 kHz
B	146.52 Hz
C	10 Hz
D	1465.20 Hz

17. - E4C02

Which of the following portions of a receiver can be effective in eliminating image signal interference?

Select	Answer
A	A properly adjusted product detector
B	A notch filter
C	A front-end filter or pre-selector
D	A narrow IF filter

18. - E4D01

What is meant by the blocking dynamic range of a receiver?

Select	Answer
A	The difference in dB between the noise floor and the level of an incoming signal which will cause 1 dB of gain compression
B	The difference in dB between the noise floor and the third order intercept point
C	The minimum difference in dB between the levels of two FM signals which will cause one signal to block the other
D	The minimum difference in dB between two signals which produce third order intermodulation products greater than the noise floor

19. - E4E03

Which of the following signals might a receiver noise blanker be able to remove from desired signals?

Select	Answer
A	Signals which appear at one IF but not another
B	Signals which appear across a wide bandwidth
C	Signals which are constant at all IF levels
D	Signals which have a sharply peaked frequency distribution

20. - E5A12

What is the half-power bandwidth of a parallel resonant circuit that has a resonant frequency of 3.7 MHz and a Q of 118?

Select	Answer
A	436.6 kHz
B	218.3 kHz
C	31.4 kHz
D	15.7 kHz

21. - E5B08

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 100 ohms, R is 100 ohms, and XL is 75 ohms?

Select	Answer
A	76 degrees with the voltage lagging the current
B	14 degrees with the voltage leading the current
C	14 degrees with the voltage lagging the current
D	76 degrees with the voltage leading the current

22. - E5C13

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

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

23. - E5D10

How can the true power be determined in an AC circuit where the voltage and current are out of phase?

Select	Answer
A	By dividing the reactive power by the power factor
B	By multiplying the apparent power times the power factor
C	By dividing the apparent power by the power factor
D	By multiplying the reactive power times the power factor

24. - E6A01

In what application is gallium arsenide used as a semiconductor material in preference to germanium or silicon?

Select	Answer
A	In high-power audio circuits
B	In high-current rectifier circuits
C	In microwave circuits
D	In very low frequency RF circuits

25. - E6B02

What is an important characteristic of a Schottky diode as compared to an ordinary silicon diode when used as a power supply rectifier?

Select	Answer
A	Much higher reverse voltage breakdown
B	Enhanced carrier retention time
C	Less forward voltage drop
D	Controlled reverse avalanche voltage

26. - E6C01

What is the function of hysteresis in a comparator?

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

27. - E6D13

What is the primary cause of inductor self-resonance?

Select	Answer
A	Inductive kickback
B	Inter-turn capacitance
C	The skin effect
D	Non-linear core hysteresis

28. - E6E01

Which of the following is true of a charge-coupled device (CCD)?

Select	Answer
A	Its phase shift changes rapidly with frequency
B	It samples an analog signal and passes it in stages from the input to the output
C	It is a CMOS analog-to-digital converter
D	It is used in a battery charger circuit

29. - E6F05

Which describes an optical shaft encoder?

Select	Answer
A	A device which detects rotation of a control by interrupting a light source with a patterned wheel
B	A device which measures the strength of a beam of light using analog to digital conversion
C	A digital encryption device often used to encrypt spacecraft control signals
D	A device for generating RTTY signals by means of a rotating light source

30. - E7A09

What logical operation is performed by an exclusive NOR gate?

Select	Answer
A	It produces logic "0" at its output only if all inputs are logic "0"
B	It produces logic "1" at its output only if all inputs are logic "1"
C	It produces logic "1" at its output if any single input is logic "1"
D	It produces logic "0" at its output if any single input is logic "1"

31. - E7B01

For what portion of a signal cycle does a Class AB amplifier operate?

Select	Answer
A	The entire cycle
B	Exactly 180 degrees
C	Less than 180 degrees
D	More than 180 degrees but less than 360 degrees

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

33. - E7D16

When several electrolytic filter capacitors are connected in series to increase the operating voltage of a power supply filter circuit, why should resistors be connected across each capacitor?

Select	Answer
A	To equalize, as much as possible, the voltage drop across each capacitor
B	All of these choices are correct
C	To provide a minimum load current to reduce voltage excursions at light loads
D	To provide a safety bleeder to discharge the capacitors when the supply is off

34. - E7E11

Which type of detector is used for demodulating SSB signals?

Select	Answer
A	Product detector
B	Phase detector
C	Discriminator
D	Phase comparator

35. - E7F16

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

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

36. - E7G01

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

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

37. - E7H06

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

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

38. - E8A06

What is the approximate ratio of PEP-to-average power in a typical single-sideband phone signal?

Select	Answer
A	25 to 1
B	1 to 1
C	2.5 to 1
D	100 to 1

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 bandwidth compression technique using Fourier transforms
D	A frequency modulation technique which uses non-harmonically related frequencies

40. - E8C06

What is the necessary bandwidth of a 170-hertz shift, 300-baud ASCII transmission?

Select	Answer
A	0.5 kHz
B	1.0 kHz
C	0.3 kHz
D	0.1 Hz

41. - E8D02

What spread spectrum communications technique uses a high speed binary bit stream to shift the phase of an RF carrier?

Select	Answer
A	Phase compandored spread spectrum
B	Frequency hopping
C	Direct sequence
D	Binary phase-shift keying

42. - E9A09

How is antenna efficiency calculated?

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

43. - E9B11

What is a disadvantage of decreasing the number of wire segments in an antenna model below the guideline of 10 segments per half-wavelength?

Select	Answer
A	Ground conductivity will not be accurately modeled
B	The resulting design will favor radiation of harmonic energy
C	The computed feed point impedance may be incorrect
D	The antenna will become mechanically unstable

44. - E9C08

What is a folded dipole antenna?

Select	Answer
A	A dipole configured to provide forward gain
B	A dipole consisting of one wavelength of wire forming a very thin loop
C	A dipole one-quarter wavelength long
D	A type of ground-plane antenna

45. - E9D01

How does the gain of an ideal parabolic dish antenna change when the operating frequency is doubled?

Select	Answer
A	Gain is multiplied by 0.707
B	Gain increases by 3 dB
C	Gain increases by 6 dB
D	Gain does not change

46. - E9E01

What system matches a higher impedance transmission line to a lower impedance antenna by connecting the line to the driven element in two places spaced a fraction of a wavelength each side of element center?

Select	Answer
A	The omega matching system
B	The delta matching system
C	The stub matching system
D	The gamma matching system

47. - E9F07

How does ladder line compare to small-diameter coaxial cable such as RG-58 at 50 MHz?

Select	Answer
A	Lower velocity factor
B	Higher SWR
C	Lower loss
D	Smaller reflection coefficient

48. - E9G07

On the Smith chart shown in Figure E9-3, what is the only straight line shown?

Select	Answer
A	The current axis
B	The voltage axis
C	The reactance axis
D	The resistance axis

49. - E9H09

Which of the following describes the construction of a receiving loop antenna?

Select	Answer
A	A large circularly polarized antenna
B	A small coil of wire tightly wound around a toroidal ferrite core
C	One or more turns of wire wound in the shape of a large open coil
D	A vertical antenna coupled to a feed line through an inductive loop of wire

50. - E0A10

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

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

Figure E9-3