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

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1. - E0A03

Over what range of frequencies are the FCC human body RF exposure limits most restrictive?

Select	Answer
A	300 to 3000 MHz
B	300 kHz to 3 MHz
C	30 to 300 MHz
D	3 to 30 MHz

2. - E1A06

Where must the carrier frequency of a CW signal be set to comply with FCC rules for 60 meter operation?

Select	Answer
A	At the lowest frequency of the channel
B	At the center frequency of the channel
C	At the highest frequency of the channel
D	On any frequency where the signal's sidebands are within the channel

3. - E1B03

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

Select	Answer
A	30 miles
B	1 mile
C	3 miles
D	10 miles

4. - E1C05

When may an automatically controlled station originate third party communications?

Select	Answer
A	Only when transmitting RTTY or data emissions
B	When approved by the National Telecommunication and Information Administration
C	Never
D	When agreed upon by the sending or receiving station

5. - E1D12

Which of the following amateur stations may transmit one-way communications?

Select	Answer
A	A local repeater or linked repeater station
B	A space station, beacon station, or telecommand station
C	All these choices are correct
D	A message forwarding station or automatically controlled digital station

6. - E1E07

What should a VE do if a candidate fails to comply with the examiner's instructions during an amateur operator license examination?

Select	Answer
A	Immediately terminate everyone's examination and close the session
B	Immediately terminate the candidate's examination
C	Warn the candidate that continued failure to comply will result in termination of the examination
D	Allow the candidate to complete the examination, but invalidate the results

7. - E1F04

Which of the following geographic descriptions approximately describes "Line A"?

Select	Answer
A	A line roughly parallel to and south of the border between the U.S. and Canada
B	A line roughly parallel to and north of the border between the U.S. and Mexico
C	A line roughly parallel to and west of the U.S. Atlantic coastline
D	A line roughly parallel to and east of the U.S. Pacific coastline

8. - E2A09

What do the terms L band and S band specify regarding satellite communications?

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

9. - E2B11

What is the function of the Vertical Interval Signaling (VIS) code sent as part of an SSTV transmission?

Select	Answer
A	To provide vertical synchronization
B	To lock the color burst oscillator in color SSTV images
C	To identify the call sign of the station transmitting
D	To identify the SSTV mode being used

10. - E2C02

Which of the following best describes the term self-spotting? in connection with HF contest operating?

Select	Answer
A	The often-prohibited practice of posting one's own call sign and frequency on a spotting network
B	A manual technique for rapidly zero beating or tuning to a station's frequency before calling that station
C	The acceptable practice of manually posting the call signs of stations on a spotting network
D	An automatic method for rapidly zero beating or tuning to a station's frequency before calling that station

11. - E2D10

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

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

12. - E2E01

Which of the following types of modulation is common for data emissions below 30 MHz?

Select	Answer
A	Pulse modulation
B	Spread spectrum
C	DTMF tones modulating an FM signal
D	FSK

13. - E3A14

What is meant by circularly polarized electromagnetic waves?

Select	Answer
A	Waves that circle the Earth
B	Waves with a rotating electric field
C	Waves with an electric field bent into a circular shape
D	Waves produced by a loop antenna

14. - E3B01

What is transequatorial propagation?

Select	Answer
A	Propagation between a point on the equator and its antipodal point
B	Propagation between two mid-latitude points at approximately the same distance north and south of the magnetic equator
C	Propagation between points located on the magnetic equator
D	Propagation between points at the same latitude

15. - E3C01

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

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

16. - E4A08

Which of the following measures SWR?

Select	Answer
A	An ohmmeter
B	An antenna analyzer
C	A spectrum analyzer
D	A Q meter

17. - E4B04

Which S parameter represents input port return loss or reflection coefficient (equivalent to VSWR)?

Select	Answer
A	S12
B	S21
C	S22
D	S11

18. - E4C03

What is the term for the suppression in an FM receiver of one signal by another stronger signal on the same frequency?

Select	Answer
A	Cross-modulation interference
B	Frequency discrimination
C	Capture effect
D	Desensitization

19. - E4D11

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

Select	Answer
A	Odd-order products of two signals in the band of interest are also likely to be within the band
B	Odd-order products overload the IF filters
C	Odd-order intermodulation produces three products for every input signal within the band of interest
D	Odd-order products are an indication of poor image rejection

20. - E4E01

What problem can occur when using an automatic notch filter (ANF) to remove interfering carriers while receiving CW signals?

Select	Answer
A	Received CW signals will appear to be modulated at the DSP clock frequency
B	Removal of the CW signal as well as the interfering carrier
C	Any nearby signal passing through the DSP system will overwhelm the desired signal
D	Ringing in the DSP filter will completely remove the spaces between the CW characters

21. - E5A08

What is the phase relationship between the current through and the voltage across a series resonant circuit at resonance?

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

22. - E5B11

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 25 ohms, R is 100 ohms, and XL is 50 ohms?

Select	Answer
A	76 degrees with the voltage leading 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 lagging the current

23. - E5C02

How are impedances described in polar coordinates?

Select	Answer
A	By X and R values
B	By phase angle and magnitude
C	By real and imaginary parts
D	By Y and G values

24. - E5D07

How many watts are consumed in a circuit having a power factor of 0.71 if the apparent power is 500VA?

Select	Answer
A	355 W
B	252 W
C	704 W
D	1.42 mW

25. - E6A06

What is the beta of a bipolar junction transistor?

Select	Answer
A	The change in collector current with respect to base current
B	The frequency at which the current gain is reduced to 0.707
C	The switching speed
D	The breakdown voltage of the base to collector junction

26. - E6B03

What type of bias is required for an LED to emit light?

Select	Answer
A	Inductive bias
B	Reverse bias
C	Forward bias
D	Zero bias

27. - E6C09

What is a Programmable Logic Device (PLD)?

Select	Answer
A	Programmable equipment used for testing digital logic integrated circuits
B	A logic circuit that can be modified during use
C	A programmable collection of logic gates and circuits in a single integrated circuit
D	A type of transistor whose gain can be changed by digital logic circuits

28. - E6D02

What is the equivalent circuit of a quartz crystal?

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

29. - E6E04

Which is the most common input and output impedance of circuits that use MMICs?

Select	Answer
A	50 ohms
B	10 ohms
C	450 ohms
D	300 ohms

30. - E6F11

What is the approximate open-circuit voltage produced by a fully illuminated silicon photovoltaic cell?

Select	Answer
A	0.1 V
B	12 V
C	0.5 V
D	1.5 V

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. - E7B18

What is a characteristic of a grounded-grid amplifier?

Select	Answer
A	Low input impedance
B	High power gain
C	High filament voltage
D	Low bandwidth

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

34. - E7D05

Which of the following types of linear voltage regulator places a constant load on the unregulated voltage source?

Select	Answer
A	A shunt regulator
B	A series regulator
C	A shunt current source
D	A constant current source

35. - E7E11

Which type of detector circuit is used for demodulating SSB signals?

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

36. - E7F07

What function is performed by a Fast Fourier Transform?

Select	Answer
A	Converting 8-bit data to 16-bit data
B	Converting analog signals to digital form
C	Converting digital signals to analog form
D	Converting digital signals from the time domain to the frequency domain

37. - E7G04

What is meant by the "op-amp input offset voltage"?

Select	Answer
A	The potential between the amplifier input terminals of the op-amp in an open loop condition
B	The differential input voltage needed to bring the open loop output voltage to zero
C	The difference between the output voltage of the op-amp and the input voltage required in the immediately following stage
D	The output voltage of the op-amp minus its input voltage

38. - E7H15

Which of these functions can be performed by a phase-locked loop?

Select	Answer
A	Photovoltaic conversion, optical coupling
B	Frequency synthesis, FM demodulation
C	Wide-band AF and RF power amplification
D	Comparison of two digital input signals, digital pulse counter

39. - 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	An abnormal condition where the converter cannot settle on a value to represent the signal
D	A small amount of noise added to the input signal to allow more precise representation of a signal over time

40. - E8B09

What is deviation ratio?

Select	Answer
A	The ratio of the carrier center frequency to the audio modulating frequency
B	The ratio of the highest audio modulating frequency to the average audio modulating frequency
C	The ratio of the audio modulating frequency to the center carrier frequency
D	The ratio of the maximum carrier frequency deviation to the highest audio modulating frequency

41. - E8C08

How does ARQ accomplish error correction?

Select	Answer
A	If errors are detected, a retransmission is requested
B	Special polynomial codes provide automatic correction
C	Special binary codes provide automatic correction
D	If errors are detected, redundant data is substituted

42. - E8D08

What parameter evaluates distortion of an AFSK signal caused by excessive input audio levels?

Select	Answer
A	Intermodulation Distortion (IMD)
B	Repeat Request Rate (RRR)
C	Signal-to-noise ratio
D	Baud rate

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	2.79 dB
B	8.15 dB
C	3.85 dB
D	6.0 dB

44. - E9B05

What type of antenna pattern is shown in Figure E9-2?

Select	Answer
A	Elevation
B	Radiation resistance
C	Azimuth
D	Polarization

45. - E9C10

Which of the following describes a Zepp antenna?

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

46. - E9D11

Which of the following conductors would be best for minimizing losses in a station's RF ground system?

Select	Answer
A	Wide flat copper strap
B	Stranded wire
C	Resistive wire, such as spark plug wire
D	Solid wire

47. - E9E02

What is the name of an antenna matching system that matches an unbalanced feed line to an antenna by feeding the driven element both at the center of the element and at a fraction of a wavelength to one side of center?

Select	Answer
A	The epsilon match
B	The stub match
C	The gamma match
D	The delta match

48. - E9F01

What is the velocity factor of a transmission line?

Select	Answer
A	The velocity of the wave in the transmission line divided by the velocity of light in a vacuum
B	The velocity of the wave in the transmission line multiplied by the velocity of light in a vacuum
C	The index of shielding for coaxial cable
D	The ratio of the characteristic impedance of the line to the terminating impedance

49. - 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	Standing wave ratio circles
C	Coaxial-length circles
D	Antenna-length circles

50. - E9H03

What is Receiving Directivity Factor (RDF)?

Select	Answer
A	Forward gain compared to average gain over the entire hemisphere
B	Relative directivity compared to isotropic
C	Forward gain compared to the gain in the reverse direction
D	Relative directivity compared to a dipole

Figure E9-2