US Amateur Radio - Amateur Extra (Element 4, 2020-2024) Practice Test

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1. - E0A07

How may dangerous levels of carbon monoxide from an emergency generator be detected?

Select	Answer
A	By the yellowish appearance of the gas
B	Any ordinary smoke detector can be used
C	By the odor
D	Only with a carbon monoxide detector

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

3. - E1B01

Which of the following constitutes a spurious emission?

Select	Answer
A	An emission outside the signal's necessary bandwidth that can be reduced or eliminated without affecting the information transmitted
B	Any transmitted signal that unintentionally interferes with another licensed radio station
C	An amateur station transmission made without the proper call sign identification
D	A signal transmitted to prevent its detection by any station other than the intended recipient

4. - E1C14

How long must an operator wait after filing a notification with the Utilities Technology Council (UTC) before operating on the 2200 meter or 630 meter band?

Select	Answer
A	Operators must not operate until approval is received
B	Operators may operate after 30 days, providing they have not been told that their station is within 1 km of PLC systems using those frequencies
C	Operations may commence immediately, and may continue unless interference is reported by the UTC
D	Operators may not operate until a test signal has been transmitted in coordination with the local power company

5. - E1D01

What is the definition of telemetry?

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

6. - E1E06

Who is responsible for the proper conduct and necessary supervision during an amateur operator license examination session?

Select	Answer
A	The FCC
B	The VEC coordinating the session
C	Each administering VE
D	The VE session manager

7. - E1F11

Which of the following best describes one of the standards that must be met by an external RF power amplifier if it is to qualify for a grant of FCC certification?

Select	Answer
A	It must be capable of external RF switching between its input and output networks
B	It must produce full legal output when driven by not more than 5 watts of mean RF input power
C	It must exhibit a gain of 0 dB or less over its full output range
D	It must satisfy the FCC's spurious emission standards when operated at the lesser of 1500 watts or its full output power

8. - E2A03

How is the signal inverted by an inverting linear transponder?

Select	Answer
A	The signal is reduced to I and Q components and the Q component is filtered out
B	The signal is passed through a mixer and the difference rather than the sum is transmitted
C	The signal is passed through a non-linear filter
D	The signal is detected and remodulated on the reverse sideband

9. - 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	120
D	60

10. - E2C11

How should you generally identify your station when attempting to contact a DX station during a contest or in a pileup?

Select	Answer
A	Send the call sign of the DX station three times, the words this is,then your call sign three times
B	Send your full call sign once or twice
C	Send your full call sign and grid square
D	Send only the last two letters of your call sign until you make contact

11. - E2D10

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

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

12. - E2E05

Which of these digital modes does not support keyboard-to-keyboard operation?

Select	Answer
A	RTTY
B	PSK31
C	PACTOR
D	MFSK

13. - E3A10

Which type of atmospheric structure can create a path for microwave propagation?

Select	Answer
A	Wind shear
B	The jet stream
C	Dust devil
D	Temperature inversion

14. - E3B05

Which amateur bands typically support long-path propagation?

Select	Answer
A	6 meters to 2 meters
B	Only 160 meters to 40 meters
C	160 meters to 10 meters
D	Only 30 meters to 10 meters

15. - E3C03

Which of the following signal paths is most likely to experience high levels of absorption when the A index or K index is elevated?

Select	Answer
A	Transequatorial
B	Polar
C	NVIS
D	Sporadic E

16. - E4A11

How should an antenna analyzer be connected when measuring antenna resonance and feed point impedance?

Select	Answer
A	Connect the antenna feed line directly to the analyzer's connector
B	Loosely couple the analyzer near the antenna base
C	Connect the analyzer via a high-impedance transformer to the antenna
D	Loosely couple the antenna and a dummy load to the analyzer

17. - E4B09

What is indicated if the current reading on an RF ammeter placed in series with the antenna feed line of a transmitter increases as the transmitter is tuned to resonance?

Select	Answer
A	The transmitter is not properly neutralized
B	There is possibly a short to ground in the feed line
C	There is an impedance mismatch between the antenna and feed line
D	There is more power going into the antenna

18. - E4C10

What is an advantage of having a variety of receiver IF bandwidths from which to select?

Select	Answer
A	Receiver power consumption can be reduced when wider bandwidth is not required
B	Multiple frequencies can be received simultaneously if desired
C	The noise figure of the RF amplifier can be adjusted to match the modulation type, thus increasing receiver sensitivity
D	Receive bandwidth can be set to match the modulation bandwidth, maximizing signal-to-noise ratio and minimizing interference

19. - E4D05

What transmitter frequencies would cause an intermodulation-product signal in a receiver tuned to 146.70 MHz when a nearby station transmits on 146.52 MHz?

Select	Answer
A	146.10 MHz and 147.30 MHz
B	146.34 MHz and 146.61 MHz
C	173.35 MHz and 139.40 MHz
D	146.88 MHz and 146.34 MHz

20. - E4E06

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

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

21. - E5A02

What is resonance in an LC or RLC circuit?

Select	Answer
A	The frequency at which the capacitive reactance equals the inductive reactance
B	The frequency at which the reactive impedance equals the resistive impedance
C	The highest frequency that will pass current
D	The lowest frequency that will pass current

22. - E5B10

What is the relationship between the AC current through an inductor and the voltage across an inductor?

Select	Answer
A	Voltage and current are 180 degrees out of phase
B	Current leads voltage by 90 degrees
C	Voltage leads current by 90 degrees
D	Voltage and current are in phase

23. - E5C01

Which of the following represents capacitive reactance in rectangular notation?

Select	Answer
A	Delta
B	-jX
C	+jX
D	Omega

24. - E5D11

What is the power factor of an RL circuit having a 60-degree phase angle between the voltage and the current?

Select	Answer
A	1.73
B	0.866
C	1.414
D	0.5

25. - E6A12

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

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

26. - E6B01

What is the most useful characteristic of a Zener diode?

Select	Answer
A	A constant voltage drop under conditions of varying current
B	A negative resistance region
C	A constant current drop under conditions of varying voltage
D	An internal capacitance that varies with the applied voltage

27. - E6C04

Which of the following is an advantage of BiCMOS logic?

Select	Answer
A	Its simplicity results in much less expensive devices than standard CMOS
B	All these choices are correct
C	It is immune to electrostatic damage
D	It has the high input impedance of CMOS and the low output impedance of bipolar transistors

28. - E6D02

What is the equivalent circuit of a quartz crystal?

Select	Answer
A	Motional capacitance, motional inductance, and loss resistance in series, all in parallel with a shunt capacitor representing electrode and stray capacitance
B	Motional capacitance, motional inductance, loss resistance, and a capacitor representing electrode and stray capacitance all in series
C	Motional capacitance, motional inductance, loss resistance, and a capacitor representing electrode and stray capacitance all in parallel
D	Motional inductance and loss resistance in series, paralleled with motional capacitance and a capacitor representing electrode and stray capacitance

29. - E6E10

What advantage does surface-mount technology offer at RF compared to using through-hole components?

Select	Answer
A	Shorter circuit-board traces
B	Components have less parasitic inductance and capacitance
C	Smaller circuit area
D	All these choices are correct

30. - E6F05

Which describes an optical shaft encoder?

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

31. - 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 only when all inputs are logic 1
C	It produces logic 0 at its output only when all inputs are logic 0
D	It produces logic 0 at its output if some but not all inputs are logic 1

32. - E7B10

In Figure E7-1, what is the purpose of R1 and R2?

Select	Answer
A	Load resistors
B	Self bias
C	Feedback
D	Voltage divider bias

33. - E7C11

Which of the following describes a receiving filter's ability to reject signals occupying an adjacent channel?

Select	Answer
A	Phase response
B	Noise factor
C	Shape factor
D	Passband ripple

34. - E7D13

What is the equation for calculating power dissipated by a series linear voltage regulator?

Select	Answer
A	Input voltage multiplied by input current
B	Input voltage divided by output current
C	Output voltage multiplied by output current
D	Voltage difference from input to output multiplied by output current

35. - E7E10

How does a diode envelope detector function?

Select	Answer
A	By breakdown of the Zener voltage
B	By rectification and filtering of RF signals
C	By mixing signals with noise in the transition region of the diode
D	By sensing the change of reactance in the diode with respect to frequency

36. - E7F14

Which of the following would allow a digital signal processing filter to create a sharper filter response?

Select	Answer
A	Higher data rate
B	Complex phasor representations
C	More taps
D	Double-precision math routines

37. - E7G02

What is ringing in a filter?

Select	Answer
A	A reduction in high frequency response
B	Undesired oscillations added to the desired signal
C	Partial cancellation of the signal over a range of frequencies
D	An echo caused by a long time delay

38. - E7H04

How is positive feedback supplied in a Colpitts oscillator?

Select	Answer
A	Through a capacitive divider
B	Through a neutralizing capacitor
C	Through a tapped coil
D	Through link coupling

39. - 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	All these choices are correct
C	Remove harmonics from the output caused by the discrete analog levels generated
D	Improve accuracy by removing out-of-sequence codes from the input

40. - E8B05

What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus-or-minus 5 kHz when the maximum modulation frequency is 3 kHz?

Select	Answer
A	0.167
B	1.67
C	0.6
D	60

41. - 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 varying the frequency shift of the transmitted signal according to a predefined algorithm
C	By transmitting a special algorithm to the receiving station along with the data characters
D	By the receiving station repeating each block of three data characters

42. - E8D01

Why are received spread spectrum signals resistant to interference?

Select	Answer
A	Signals not using the spread spectrum algorithm are suppressed in the receiver
B	The high power used by a spread spectrum transmitter keeps its signal from being easily overpowered
C	If interference is detected by the receiver it will signal the transmitter to change frequencies
D	The receiver is always equipped with a digital blanker

43. - E9A08

What is antenna bandwidth?

Select	Answer
A	The angle between the half-power radiation points
B	The angle formed between two imaginary lines drawn through the element ends
C	Antenna length divided by the number of elements
D	The frequency range over which an antenna satisfies a performance requirement

44. - E9B08

What is the far field of an antenna?

Select	Answer
A	The region where radiated power dissipates over a specified time period
B	The region where the shape of the antenna pattern is independent of distance
C	The region where radiated field strengths are constant
D	The region of the ionosphere where radiated power is not refracted

45. - E9C07

What is the approximate feed point impedance at the center of a two-wire folded dipole antenna?

Select	Answer
A	300 ohms
B	72 ohms
C	50 ohms
D	450 ohms

46. - E9D02

How can linearly polarized Yagi antennas be used to produce circular polarization?

Select	Answer
A	Stack two Yagis fed 90 degrees out of phase to form an array with the respective elements in parallel planes
B	Arrange two Yagis perpendicular to each other with the driven elements at the same point on the boom fed 90 degrees out of phase
C	Stack two Yagis fed in phase to form an array with the respective elements in parallel planes
D	Arrange two Yagis collinear to each other with the driven elements fed 180 degrees out of phase

47. - E9E04

What is the purpose of the series capacitor in a gamma-type antenna matching network?

Select	Answer
A	To provide a rejection notch that prevents the radiation of harmonics
B	To provide DC isolation between the feed line and the antenna
C	To transform the antenna impedance to a higher value
D	To cancel the inductive reactance of the matching network

48. - E9F05

What is the approximate physical length of a solid polyethylene dielectric coaxial transmission line that is electrically 1/4 wavelength long at 14.1 MHz?

Select	Answer
A	10.6 meters
B	4.3 meters
C	3.5 meters
D	5.3 meters

49. - E9G03

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

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

50. - E9H10

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

Select	Answer
A	By reducing the permeability of the loop shield
B	By winding adjacent turns in opposing directions
C	By utilizing high impedance wire for the coupling loop
D	By increasing the number of turns and/or the area

Figure E7-1