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

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1. - 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 in areas where the total MPE limit is exceeded.
B	Only the most powerful transmitter
C	Each transmitter operating with a duty cycle greater than 50 percent
D	Only commercial transmitters

2. - E1A01

Which of the following carrier frequencies is illegal for LSB AFSK emissions on the 17 meter band RTTY and data segment of 18.068 to 18.110 MHz?

Select	Answer
A	18.068 MHz
B	18.110 MHz
C	18.107 MHz
D	18.100 MHz

3. - E1B10

What frequencies are authorized to an amateur station operating under RACES rules?

Select	Answer
A	Specific local government channels
B	Military Auxiliary Radio System (MARS) channels
C	All amateur service frequencies authorized to the control operator
D	Specific segments in the amateur service MF, HF, VHF and UHF bands

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 may operate after 30 days, providing they have not been told that their station is within 1 km of PLC systems using those frequencies
B	Operators must not operate until approval is received
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. - E1D04

Which of the following is required in the identification transmissions from a balloon-borne telemetry station?

Select	Answer
A	The station's six-character Maidenhead grid locator
B	Call sign
C	The output power of the balloon transmitter
D	All these choices are correct

6. - 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	Send the application form to the FCC and inform the FCC of the grade
C	Destroy the application form
D	Maintain the application form with the VEC's records

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

8. - E2A03

How is the signal inverted by an inverting linear transponder?

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

9. - E2B06

What is vestigial sideband modulation?

Select	Answer
A	Amplitude modulation in which one complete sideband and a portion of the other are transmitted
B	Spread spectrum modulation achieved by applying FM modulation following single sideband amplitude modulation
C	Narrow-band FM modulation achieved by filtering one sideband from the audio before frequency modulating the carrier
D	A type of modulation in which one sideband is inverted

10. - E2C04

Which of the following frequencies are sometimes used for amateur radio mesh networks?

Select	Answer
A	HF frequencies where digital communications are permitted
B	Cable TV channels 41 through 43
C	The 60 meter band channel centered on 5373 kHz
D	Frequencies shared with various unlicensed wireless data services

11. - E2D11

Which of the following data are used by the APRS network to communicate station location?

Select	Answer
A	Radio direction finding spectrum analysis
B	Polar coordinates
C	Time and frequency
D	Latitude and longitude

12. - E2E07

Which of the following is a possible reason that attempts to initiate contact with a digital station on a clear frequency are unsuccessful?

Select	Answer
A	Your transmit frequency is incorrect
B	Another station you are unable to hear is using the frequency
C	The protocol version you are using is not supported by the digital station
D	All these choices are correct

13. - E3A06

What might help to restore contact when DX signals become too weak to copy across an entire HF band a few hours after sunset?

Select	Answer
A	Switch to a higher frequency HF band
B	Switch to a lower frequency HF band
C	Wait 24 hours before attempting another communication on the band
D	Wait 90 minutes or so for the signal degradation to pass

14. - E3B12

What is the primary characteristic of chordal hop propagation?

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

15. - E3C01

What does the radio communication term "ray tracing" describe?

Select	Answer
A	The process in which an electronic display presents a pattern
B	Determining the radiation pattern from an array of antennas
C	Modeling a radio wave's path through the ionosphere
D	Evaluating high voltage sources for x-rays

16. - E4A05

What is the purpose of the prescaler function on a frequency counter?

Select	Answer
A	It amplifies low-level signals for more accurate counting
B	It prevents oscillation in a low-frequency counter circuit
C	It divides a higher frequency signal so a low-frequency counter can display the input frequency
D	It multiplies a higher frequency signal so a low-frequency counter can display the operating frequency

17. - E4B11

Which of the following can be measured with a vector network analyzer?

Select	Answer
A	Input impedance
B	All these choices are correct
C	Output impedance
D	Reflection coefficient

18. - E4C14

What transmit frequency might generate an image response signal in a receiver tuned to 14.300 MHz and that uses a 455 kHz IF frequency?

Select	Answer
A	13.845 MHz
B	15.210 MHz
C	14.445 MHz
D	14.755 MHz

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

20. - E4E06

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

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

21. - E5A11

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

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

22. - E5B01

What is the term for the time required for the capacitor in an RC circuit to be charged to 63.2% of the applied voltage or to discharge to 36.8% of its initial voltage?

Select	Answer
A	One time constant
B	A time factor of one
C	An exponential rate of one
D	One exponential period

23. - E5C04

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

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

24. - E5D13

How many watts are consumed in a circuit consisting of a 100-ohm resistor in series with a 100-ohm inductive reactance drawing 1 ampere?

Select	Answer
A	200 watts
B	100 watts
C	141.4 watts
D	70.7 watts

25. - E6A10

In Figure E6-1, what is the schematic symbol for an N-channel dual-gate MOSFET?

Select	Answer
A	2
B	6
C	5
D	4

26. - E6B04

What type of semiconductor device is designed for use as a voltage-controlled capacitor?

Select	Answer
A	Varactor diode
B	Tunnel diode
C	Zener diode
D	Silicon-controlled rectifier

27. - E6C06

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

Select	Answer
A	Bandwidth is very limited
B	Large bypass capacitance is inherent
C	The input switching threshold is about one-half the power supply voltage
D	The input switching threshold is about two times the power supply voltage

28. - E6D11

Which type of core material decreases inductance when inserted into a coil?

Select	Answer
A	Brass
B	Ferrite
C	Ceramic
D	Powdered iron

29. - E6E03

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

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

30. - E6F09

What is the efficiency of a photovoltaic cell?

Select	Answer
A	Cost per kilowatt-hour generated
B	The output RF power divided by the input DC power
C	The open-circuit voltage divided by the short-circuit current under full illumination
D	The relative fraction of light that is converted to current

31. - E7A09

What logical operation is performed by an exclusive NOR gate?

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

32. - E7B13

Which of the following describes an emitter follower (or common collector) amplifier?

Select	Answer
A	An OR circuit with only one emitter used for output
B	A differential amplifier with both inputs fed to the emitter of the input transistor
C	A two-transistor amplifier with the emitters sharing a common bias resistor
D	An amplifier with a low impedance output that follows the base input voltage

33. - 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 low-pass filter
B	It is a high-pass filter
C	It is a notch filter
D	It is a band-pass filter

34. - E7D06

What is the purpose of Q1 in the circuit shown in Figure E7-2?

Select	Answer
A	It provides a constant load for the voltage source
B	It controls the current supplied to the load
C	It provides D1 with current
D	It provides negative feedback to improve regulation

35. - E7E10

How does a diode envelope detector function?

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

36. - 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	8 bits
C	4 bits
D	10 bits

37. - E7G03

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

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

38. - E7H04

How is positive feedback supplied in a Colpitts oscillator?

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

39. - E8A04

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

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

40. - E8B07

Orthogonal Frequency Division Multiplexing is a technique used for which type of amateur communication?

Select	Answer
A	OFDM signals are not allowed on amateur bands
B	EME
C	High-speed digital modes
D	Extremely low-power contacts

41. - E8C02

What is the definition of symbol rate in a digital transmission?

Select	Answer
A	The number of characters carried per second by the station-to-station link
B	The number of control characters in a message packet
C	The rate at which the waveform changes to convey information
D	The duration of each bit in a message sent over the air

42. - E8D05

What is the most common method of reducing key clicks?

Select	Answer
A	High-pass filters at the transmitter output
B	Low-pass filters at the transmitter output
C	Reduce keying waveform rise and fall times
D	Increase keying waveform rise and fall times

43. - E9A12

How much gain does an antenna have compared to a 1/2-wavelength dipole when it has 6 dB gain over an isotropic antenna?

Select	Answer
A	8.15 dB
B	6.0 dB
C	2.79 dB
D	3.85 dB

44. - E9B04

What is the front-to-back ratio of the radiation pattern shown in Figure E92?

Select	Answer
A	28 dB
B	38 dB
C	3 dB
D	15 dB

45. - E9C10

Which of the following describes a Zepp antenna?

Select	Answer
A	An omni-directional antenna commonly used for satellite communications
B	A vertical array capable of quickly changing the direction of maximum radiation by changing phasing lines
C	A dipole constructed from zip cord
D	An end-fed dipole antenna

46. - E9D04

Why should an HF mobile antenna loading coil have a high ratio of reactance to resistance?

Select	Answer
A	To swamp out harmonics
B	To minimize losses
C	To lower the radiation angle
D	To minimize the Q

47. - E9E11

What is the primary purpose of phasing lines when used with an antenna having multiple driven elements?

Select	Answer
A	It prevents reflected power from traveling back down the feed line and causing harmonic radiation from the transmitter
B	It creates a low-angle radiation pattern
C	It ensures that each driven element operates in concert with the others to create the desired antenna pattern
D	It allows single-band antennas to operate on other bands

48. - E9F12

What impedance does a 1/4-wavelength transmission line present to a generator when the line is open at the far end?

Select	Answer
A	Very high impedance
B	Very low impedance
C	The same as the input impedance to the generator
D	The same as the characteristic impedance of the line

49. - E9G05

Which of the following is a common use for a Smith chart?

Select	Answer
A	Determine the length and position of an impedance matching stub
B	Determine the impedance of a transmission line, given the physical dimensions
C	Determine the loss/100 feet of a transmission line, given the velocity factor and conductor materials
D	Determine the gain of an antenna given the physical and electrical parameters

50. - E9H09

What is a Pennant antenna?

Select	Answer
A	A stealth antenna built to look like a flagpole
B	A four-element, high-gain vertical array invented by George Pennant
C	A small, vertically oriented receiving antenna consisting of a triangular loop terminated in approximately 900 ohms
D	A form of rhombic antenna terminated in a variable capacitor to provide frequency diversity

Figure E6-1

Figure E7-2