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 operator of the originating station
C	The control operators of all the stations in the system not authenticating the source from which they accept communications
D	The control operators of all the stations in the system

2. - E1B03

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

Select	Answer
A	30 miles
B	3 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	Business-related messages for non-profit organizations
C	Messages intended for connection to users of the maritime satellite service
D	All of these choices are correct

4. - E1D02

What is the amateur satellite service?

Select	Answer
A	A radio navigation service using satellites for the purpose of self training, intercommunication and technical studies carried out by amateurs
B	A spacecraft launching service for amateur-built satellites
C	A radio communications service using amateur radio stations on satellites
D	A radio communications service using stations on Earth satellites for public service broadcast

5. - E1E12

What must the VE team do with the application form if the examinee does not pass the exam?

Select	Answer
A	Return the application document to the examinee
B	Maintain the application form with the VEC's records
C	Send the application form to the FCC and inform the FCC of the grade
D	Destroy the application form

6. - E1F01

On what frequencies are spread spectrum transmissions permitted?

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

7. - E2A09

What do the terms L band and S band specify with regard to satellite communications?

Select	Answer
A	FM and Digital Store-and-Forward systems
B	The 2 meter and 70 centimeter bands
C	Which sideband to use
D	The 23 centimeter and 13 centimeter bands

8. - E2B01

How many times per second is a new frame transmitted in a fast-scan (NTSC) television system?

Select	Answer
A	90
B	30
C	60
D	120

9. - E2C10

Why might a DX station state that they are listening on another frequency?

Select	Answer
A	To separate the calling stations from the DX station
B	Because the DX station may be transmitting on a frequency that is prohibited to some responding stations
C	To improve operating efficiency by reducing interference
D	All of these choices are correct

10. - E2D06

Which of the following describes a method of establishing EME contacts?

Select	Answer
A	High speed CW identification to avoid fading
B	Time synchronous transmissions alternately from each station
C	Storing and forwarding digital messages
D	Judging optimum transmission times by monitoring beacons reflected from the Moon

11. - E2E05

Which type of digital mode does not support keyboard-to-keyboard operation?

Select	Answer
A	PSK31
B	MFSK
C	RTTY
D	Winlink

12. - E3A07

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

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

13. - E3B12

What is the primary characteristic of chordal hop propagation?

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

14. - E3C04

What does the value of Bz (B sub Z) represent?

Select	Answer
A	Duration of long-delayed echoes
B	Critical frequency for vertical transmissions
C	Geomagnetic field stability
D	Direction and strength of the interplanetary magnetic field

15. - E4A13

How is the compensation of an oscilloscope probe typically adjusted?

Select	Answer
A	A frequency standard is displayed and the probe is adjusted until the deflection time is accurate
B	A high frequency sine wave is displayed and the probe is adjusted for maximum amplitude
C	A DC voltage standard is displayed and the probe is adjusted until the displayed voltage is accurate
D	A square wave is displayed and the probe is adjusted until the horizontal portions of the displayed wave are as nearly flat as possible

16. - E4B02

What is an advantage of using a bridge circuit to measure impedance?

Select	Answer
A	It is relatively immune to drift in the signal generator source
B	It can display results directly in Smith chart format
C	It is very precise in obtaining a signal null
D	It provides an excellent match under all conditions

17. - E4C07

What does the MDS of a receiver represent?

Select	Answer
A	The maximum detectable spectrum
B	The minimum discernible signal
C	The meter display sensitivity
D	The multiplex distortion stability

18. - E4D11

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

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

19. - E4E14

What is one type of electrical interference that might be caused by the operation of a nearby personal computer?

Select	Answer
A	A whining type noise that continually pulses off and on
B	A clicking noise at intervals of a few seconds
C	A loud AC hum in the audio output of your station receiver
D	The appearance of unstable modulated or unmodulated signals at specific frequencies

20. - E5A13

What is an effect of increasing Q in a resonant circuit?

Select	Answer
A	Fewer components are needed for the same performance
B	Phase shift can become uncontrolled
C	Internal voltages and circulating currents increase
D	Parasitic effects are minimized

21. - E5B13

What letter is commonly used to represent susceptance?

Select	Answer
A	B
B	X
C	Y
D	G

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 5
B	Point 4
C	Point 6
D	Point 2

23. - E5D04

Why are short connections necessary at microwave frequencies?

Select	Answer
A	To increase neutralizing resistance
B	Because of ground reflections
C	To reduce noise figure
D	To reduce phase shift along the connection

24. - E6A11

In Figure E6-2, what is the schematic symbol for a P-channel junction FET?

Select	Answer
A	3
B	2
C	1
D	6

25. - E6B06

Which of the following is a common use of a hot-carrier diode?

Select	Answer
A	As a constant voltage reference in a power supply
B	As a VHF/UHF mixer or detector
C	As balanced mixers in FM generation
D	As a variable capacitance in an automatic frequency control circuit

26. - E6C06

Why do CMOS digital integrated circuits have high immunity to noise on the input signal or power supply?

Select	Answer
A	The input switching threshold is about one-half the power supply voltage
B	Input signals are stronger
C	Larger bypass capacitors are used in CMOS circuit design
D	The input switching threshold is about two times the power supply voltage

27. - E6D07

What is the usable frequency range of inductors that use toroidal cores, assuming a correct selection of core material for the frequency being used?

Select	Answer
A	From less than 20 Hz to approximately 300 MHz
B	From about 100 kHz to at least 1000 GHz
C	From approximately 10 Hz to no more than 3000 kHz
D	From a few kHz to no more than 30 MHz

28. - E6E03

Which of the following materials is likely to provide the highest frequency of operation when used in MMICs?

Select	Answer
A	Silicon
B	Silicon nitride
C	Gallium nitride
D	Silicon dioxide

29. - E6F03

What is the most common configuration of an optoisolator or optocoupler?

Select	Answer
A	A lens and a photomultiplier
B	A frequency modulated helium-neon laser
C	An amplitude modulated helium-neon laser
D	An LED and a phototransistor

30. - E7A02

What is the function of a decade counter digital IC?

Select	Answer
A	It decodes a decimal number for display on a seven segment LED display
B	It adds two decimal numbers together
C	It produces one output pulse for every ten input pulses
D	It produces ten output pulses for every input pulse

31. - E7B04

Where on the load line of a Class A common emitter amplifier would bias normally be set?

Select	Answer
A	At a point where the load line intersects the zero bias current curve
B	Approximately half-way between saturation and cutoff
C	Where the load line intersects the voltage axis
D	At a point where the bias resistor equals the load resistor

32. - E7C15

What is a crystal lattice filter?

Select	Answer
A	An audio filter made with four quartz crystals that resonate at 1kHz intervals
B	A power supply filter made with interlaced quartz crystals
C	A filter with narrow bandwidth and steep skirts made using quartz crystals
D	A filter with wide bandwidth and shallow skirts made using quartz crystals

33. - E7D14

What is one purpose of a "bleeder" resistor in a conventional unregulated power supply?

Select	Answer
A	To cut down on waste heat generated by the power supply
B	To balance the low-voltage filament windings
C	To improve output voltage regulation
D	To boost the amount of output current

34. - E7E08

What are the principal frequencies that appear at the output of a mixer circuit?

Select	Answer
A	The two input frequencies along with their sum and difference frequencies
B	The sum, difference and square root of the input frequencies
C	Two and four times the original frequency
D	1.414 and 0.707 times the input frequency

35. - E7F06

What is the minimum number of bits required for an analog-to-digital converter to sample a signal with a range of 1 volt at a resolution of 1 millivolt?

Select	Answer
A	6 bits
B	10 bits
C	8 bits
D	4 bits

36. - E7G03

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

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

37. - E7H08

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

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

38. - E8A10

What is the purpose of a low pass filter used in conjunction with a digital-to-analog converter?

Select	Answer
A	Lower the input bandwidth to increase the effective resolution
B	Remove harmonics from the output caused by the discrete analog levels generated
C	Improve accuracy by removing out of sequence codes from the input
D	All of these choices are correct

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 increases as the RF carrier frequency increases
C	It does not depend on the RF carrier frequency
D	It varies with the square root of the RF carrier frequency

40. - E8C01

How is Forward Error Correction implemented?

Select	Answer
A	By transmitting extra data that may be used to detect and correct transmission errors
B	By the receiving station repeating each block of three data characters
C	By transmitting a special algorithm to the receiving station along with the data characters
D	By varying the frequency shift of the transmitted signal according to a predefined algorithm

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

42. - E9A03

Why would one need to know the feed point impedance of an antenna?

Select	Answer
A	To match impedances in order to minimize standing wave ratio on the transmission line
B	To calculate the front-to-back ratio of the antenna
C	To calculate the front-to-side ratio of the antenna
D	To measure the near-field radiation density from a transmitting antenna

43. - E9B03

In the antenna radiation pattern shown in Figure E9-1, what is the front-to-side ratio?

Select	Answer
A	12 dB
B	14 dB
C	18 dB
D	24 dB

44. - E9C06

What is the effect of a terminating resistor on a rhombic antenna?

Select	Answer
A	It reflects the standing waves on the antenna elements back to the transmitter
B	It changes the radiation pattern from horizontal to vertical polarization
C	It decreases the ground loss
D	It changes the radiation pattern from bidirectional to unidirectional

45. - E9D09

What is the function of a loading coil used as part of an HF mobile antenna?

Select	Answer
A	To cancel capacitive reactance
B	To lower the Q
C	To lower the losses
D	To increase the SWR bandwidth

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 gamma matching system
B	The omega matching system
C	The delta matching system
D	The stub matching system

47. - E9F16

Which of the following is a significant difference between foam dielectric coaxial cable and solid dielectric cable, assuming all other parameters are the same?

Select	Answer
A	Foam dielectric has lower loss per unit of length
B	Foam dielectric has higher velocity factor
C	All of these choices are correct
D	Foam dielectric has lower safe operating voltage limits

48. - E9G02

What type of coordinate system is used in a Smith chart?

Select	Answer
A	Resistance circles and reactance arcs
B	Voltage lines and current chords
C	Resistance lines and reactance chords
D	Voltage circles and current arcs

49. - E9H10

How can the output voltage of a multiple turn receiving loop antenna be increased?

Select	Answer
A	By increasing the number of wire turns in the loop and reducing the area of the loop structure
B	By reducing the permeability of the loop shield
C	By increasing either the number of wire turns in the loop or the area of the loop structure or both
D	By winding adjacent turns in opposing directions

50. - E0A11

Which of the following injuries can result from using high-power UHF or microwave transmitters?

Select	Answer
A	Ingestion of ozone gas from the cooling system
B	Blood clotting from the intense magnetic field
C	Localized heating of the body from RF exposure in excess of the MPE limits
D	Hearing loss caused by high voltage corona discharge

Figure E5-2

Figure E6-2

Figure E9-1