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

2. - E1B11

What is the permitted mean power of any spurious emission relative to the mean power of the fundamental emission from a station transmitter or external RF amplifier installed after January 1, 2003 and transmitting on a frequency below 30 MHZ?

Select	Answer
A	At least 43 dB below
B	At least 63 dB below
C	At least 53 dB below
D	At least 73 dB below

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	The use of devices and procedures for control so that the control operator does not have to be present at a control point
D	A station operating with its output power controlled automatically

4. - E1D06

Which of the following is a requirement of a space station?

Select	Answer
A	The space station must cease all transmissions after 5 years
B	The space station must be capable of terminating transmissions by telecommand when directed by the FCC
C	All of these choices are correct
D	The space station must be capable of changing its orbit whenever such a change is ordered by NASA

5. - E1E02

Where are the questions for all written U.S. amateur license examinations listed?

Select	Answer
A	In a question pool maintained by all the VECs
B	In FCC Part 97
C	In a question pool maintained by the FCC
D	In the appropriate FCC Report and Order

6. - E1F12

Who may be the control operator of an auxiliary station?

Select	Answer
A	Only General, Advanced or Amateur Extra Class operators
B	Only Amateur Extra Class operators
C	Only Technician, General, Advanced or Amateur Extra Class operators
D	Any licensed amateur operator

7. - E2A12

What is one way to predict the location of a satellite at a given time?

Select	Answer
A	By subtracting the mean anomaly from the orbital inclination
B	By calculations using the Keplerian elements for the specified satellite
C	By adding the mean anomaly to the orbital inclination
D	By means of the Doppler data for the specified satellite

8. - E2B16

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

Select	Answer
A	PAL
B	DRM
C	Scottie
D	NTSC

9. - E2C04

What type of transmission is most often used for a ham radio mesh network?

Select	Answer
A	Frequency division multiplex in the 24 GHz band
B	Spread spectrum in the 2.4 GHz band
C	Multiple Frequency Shift Keying in the 10 GHz band
D	Store and forward on the 440 MHz band

10. - E2D02

Which of the following is a good technique for making meteor scatter contacts?

Select	Answer
A	Short transmission with rapidly repeated call signs and signal reports
B	Use of high speed CW or digital modes
C	15 second timed transmission sequences with stations alternating based on location
D	All of these choices are correct

11. - E2E09

Which of the following HF digital modes uses variable-length coding for bandwidth efficiency?

Select	Answer
A	PSK31
B	PACTOR
C	MT63
D	RTTY

12. - E3A05

Tropospheric propagation of microwave signals often occurs along what weather related structure?

Select	Answer
A	Lightning discharges
B	Sprites and jets
C	Warm and cold fronts
D	Gray-line

13. - E3B01

What is transequatorial propagation?

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

14. - E3C08

What does the space weather term G5 mean?

Select	Answer
A	Moderate solar wind
B	An extreme geomagnetic storm
C	Very low solar activity
D	Waning sunspot numbers

15. - E4A02

Which of the following parameters would a spectrum analyzer display on the vertical and horizontal axes?

Select	Answer
A	RF amplitude and frequency
B	RF amplitude and time
C	SWR and frequency
D	SWR and time

16. - E4B12

What is the significance of voltmeter sensitivity expressed in ohms per volt?

Select	Answer
A	When used as an ammeter, the full scale reading in amps divided by ohms per volt rating will determine the size of shunt needed
B	When used as a galvanometer, the reading in volts multiplied by the ohms per volt rating will determine the power drawn by the device under test
C	When used as an ohmmeter, the reading in ohms divided by the ohms per volt rating will determine the voltage applied to the circuit
D	The full scale reading of the voltmeter multiplied by its ohms per volt rating will indicate the input impedance of the voltmeter

17. - E4C06

A CW receiver with the AGC off has an equivalent input noise power density of -174 dBm/Hz. What would be the level of an unmodulated carrier input to this receiver that would yield an audio output SNR of 0 dB in a 400 Hz noise bandwidth?

Select	Answer
A	-148 dBm
B	-155 dBm
C	-164 dBm
D	-174 dBm

18. - E4D04

Which of the following may reduce or eliminate intermodulation interference in a repeater caused by another transmitter operating in close proximity?

Select	Answer
A	A Class C final amplifier
B	A band-pass filter in the feed line between the transmitter and receiver
C	A Class D final amplifier
D	A properly terminated circulator at the output of the transmitter

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	Ringing in the DSP filter will completely remove the spaces between the CW characters
C	A DSP filter can remove the desired signal at the same time as it removes interfering signals
D	Received CW signals will appear to be modulated at the DSP clock frequency

20. - E5A15

Which of the following can increase Q for inductors and capacitors?

Select	Answer
A	Higher self-resonant frequency
B	Lower self-resonant frequency
C	Lower losses
D	Lower reactance

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	It is unchanged
C	The sign is reversed
D	The magnitude of the susceptance is the reciprocal of the magnitude of the reactance

22. - E5C09

When using rectangular coordinates to graph the impedance of a circuit, what does the horizontal axis represent?

Select	Answer
A	The sum of the reactive and resistive components
B	Resistive component
C	Reactive component
D	The difference between the resistive and reactive components

23. - E5D07

What determines the strength of the magnetic field around a conductor?

Select	Answer
A	The ratio of the current to the resistance
B	The amount of current flowing through the conductor
C	The resistance divided by the current
D	The diameter of the conductor

24. - E6A05

What is the alpha of a bipolar junction transistor?

Select	Answer
A	The change of collector current with respect to gate current
B	The change of base current with respect to collector current
C	The change of collector current with respect to emitter current
D	The change of collector current with respect to base current

25. - E6B07

What is the failure mechanism when a junction diode fails due to excessive current?

Select	Answer
A	Insufficient forward voltage
B	Excessive junction temperature
C	Charge carrier depletion
D	Excessive inverse voltage

26. - E6C12

What is BiCMOS logic?

Select	Answer
A	A FET logic family based on bimetallic semiconductors
B	A logic device with two CMOS circuits per package
C	A logic family based on bismuth CMOS devices
D	An integrated circuit logic family using both bipolar and CMOS transistors

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	2 turns
B	43 turns
C	4 turns
D	229 turns

28. - E6E12

Why are high-power RF amplifier ICs and transistors sometimes mounted in ceramic packages?

Select	Answer
A	Enhanced sensitivity to light
B	To provide a low-pass frequency response
C	Better dissipation of heat
D	High-voltage insulating ability

29. - E6F13

What is a liquid crystal display (LCD)?

Select	Answer
A	A display utilizing a crystalline liquid and polarizing filters which becomes opaque when voltage is applied
B	A frequency-determining unit for a transmitter or receiver
C	A modern replacement for a quartz crystal oscillator which displays its fundamental frequency
D	A display that uses a glowing liquid to remain brightly lit in dim light

30. - E7A01

Which is a bi-stable circuit?

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

31. - E7B15

What is one way to prevent thermal runaway in a bipolar transistor amplifier?

Select	Answer
A	All of these choices are correct
B	Neutralization
C	Use a resistor in series with the emitter
D	Select transistors with high beta

32. - E7C08

Which of the following factors has the greatest effect in helping determine the bandwidth and response shape of a crystal ladder filter?

Select	Answer
A	The gain of the RF stage preceding the filter
B	The relative frequencies of the individual crystals
C	The amplitude of the signals passing through the filter
D	The DC voltage applied to the quartz crystal

33. - E7D10

What is the primary reason that a high-frequency switching type high voltage power supply can be both less expensive and lighter in weight than a conventional power supply?

Select	Answer
A	The high frequency inverter design uses much smaller transformers and filter components for an equivalent power output
B	It uses a diode bridge rectifier for increased output
C	The inverter design does not require any output filtering
D	It uses a large power factor compensation capacitor to create free power from the unused portion of the AC cycle

34. - E7E07

What is meant by the term baseband in radio communications?

Select	Answer
A	The unmodulated bandwidth of the transmitted signal
B	The lowest frequency band that the transmitter or receiver covers
C	The basic oscillator frequency in an FM transmitter that is multiplied to increase the deviation and carrier frequency
D	The frequency components present in the modulating signal

35. - E7F03

What type of digital signal processing filter is used to generate an SSB signal?

Select	Answer
A	A notch filter
B	An adaptive filter
C	An elliptical filter
D	A Hilbert-transform filter

36. - E7G10

What absolute voltage gain can be expected from the circuit in Figure E7-4 when R1 is 1800 ohms and RF is 68 kilohms?

Select	Answer
A	0.03
B	38
C	76
D	1

37. - E7H10

What information is contained in the lookup table of a direct digital frequency synthesizer?

Select	Answer
A	The phase relationship between a reference oscillator and the output waveform
B	The synthesizer frequency limits and frequency values stored in the radio memories
C	The phase relationship between a voltage-controlled oscillator and the output waveform
D	The amplitude values that represent a sine-wave output

38. - E8A04

What is "dither" with respect to analog to digital converters?

Select	Answer
A	A method of decimation by randomly skipping samples
B	An error caused by irregular quantization step size
C	A small amount of noise added to the input signal to allow more precise representation of a signal over time
D	An abnormal condition where the converter cannot settle on a value to represent the signal

39. - E8B08

What describes Orthogonal Frequency Division Multiplexing?

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

40. - E8C05

What is the necessary bandwidth of a 13-WPM international Morse code transmission?

Select	Answer
A	Approximately 104 Hz
B	Approximately 52 Hz
C	Approximately 13 Hz
D	Approximately 26 Hz

41. - E8D07

What is a common cause of overmodulation of AFSK signals?

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

42. - E9A16

What is the effective radiated power relative to a dipole of a repeater station with 200 watts transmitter power output, 4 dB feed line loss, 3.2 dB duplexer loss, 0.8 dB circulator loss, and 10 dBd antenna gain?

Select	Answer
A	317 watts
B	2000 watts
C	300 watts
D	126 watts

43. - E9B08

How can the approximate beam-width in a given plane of a directional antenna be determined?

Select	Answer
A	Measure the ratio of the signal strengths of the radiated power lobes from the front and side of the antenna
B	Draw two imaginary lines through the ends of the elements and measure the angle between the lines
C	Measure the ratio of the signal strengths of the radiated power lobes from the front and rear of the antenna
D	Note the two points where the signal strength of the antenna is 3 dB less than maximum and compute the angular difference

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

45. - E9D10

What happens to feed point impedance at the base of a fixed length HF mobile antenna as the frequency of operation is lowered?

Select	Answer
A	The radiation resistance increases and the capacitive reactance decreases
B	The radiation resistance decreases and the capacitive reactance decreases
C	The radiation resistance decreases and the capacitive reactance increases
D	The radiation resistance increases and the capacitive reactance increases

46. - E9E09

Which of these matching systems is an effective method of connecting a 50 ohm coaxial cable feed line to a grounded tower so it can be used as a vertical antenna?

Select	Answer
A	Hairpin match
B	Gamma match
C	Double-bazooka match
D	All of these choices are correct

47. - E9F07

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

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

48. - E9G09

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

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

49. - E9H05

What is the main drawback of a wire-loop antenna for direction finding?

Select	Answer
A	It has a bidirectional pattern
B	It is practical for use only on VHF bands
C	It receives equally well in all directions
D	It is non-rotatable

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	Each transmitter that produces 5 percent or more of its MPE limit at accessible locations
B	Only commercial transmitters
C	Each transmitter operating with a duty-cycle greater than 50 percent
D	Only the most powerful transmitter

Figure E7-4