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

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1. - E0A08

What does SAR measure?

Select	Answer
A	Synthetic Aperture Ratio of the human body
B	The rate at which RF energy is absorbed by the body
C	Signal Amplification Rating
D	The rate of RF energy reflected from stationary terrain

2. - E1A02

When using a transceiver that displays the carrier frequency of phone signals, which of the following displayed frequencies represents the lowest frequency at which a properly adjusted LSB emission will be totally within the band?

Select	Answer
A	1 kHz above the lower band edge
B	3 kHz above the lower band edge
C	300 Hz above the lower band edge
D	The exact lower band edge

3. - E1B11

What does PRB-1 require of regulations affecting amateur radio?

Select	Answer
A	Amateur radio operations must be permitted in any private residence
B	Use of wireless devices in a vehicle is exempt from regulation
C	No limitations may be placed on antenna size or placement
D	Reasonable accommodations of amateur radio must be made

4. - E1C06

Which of the following is required in order to operate in accordance with CEPT rules in foreign countries where permitted?

Select	Answer
A	You must bring a copy of FCC Public Notice DA 16-1048
B	You must append "/CEPT" to your call sign
C	You must identify in the official language of the country in which you are operating
D	The U.S. embassy must approve of your operation

5. - E1D05

What must be posted at the station location of a station being operated by telecommand on or within 50 km of the earth's surface?

Select	Answer
A	All these choices are correct
B	A label with the name, address, and telephone number of the control operator
C	A label with the name, address, and telephone number of the station licensee
D	A photocopy of the station license

6. - E1E09

What may be the penalty for a VE who fraudulently administers or certifies an examination?

Select	Answer
A	A fine of up to $1000 per occurrence
B	A sentence of up to one year in prison
C	All these choices are correct
D	Revocation of the VE's amateur station license grant and the suspension of the VE's amateur operator license grant

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

8. - E2A05

What do the letters in a satellite's mode designator specify?

Select	Answer
A	Power limits for uplink and downlink transmissions
B	The polarization of uplink and downlink signals
C	The uplink and downlink frequency ranges
D	The location of the ground control station

9. - E2B02

How many horizontal lines make up a fast-scan (NTSC) television frame?

Select	Answer
A	525
B	60
C	30
D	1080

10. - E2C09

What type of equipment is commonly used to implement an amateur radio mesh network?

Select	Answer
A	A wireless router running custom firmware
B	A 2 meter VHF transceiver with a 1200 baud modem
C	An optical cable connection between the USB ports of 2 separate computers
D	A 440 MHz transceiver with a 9600 baud modem

11. - E2D07

What digital protocol is used by APRS?

Select	Answer
A	AMTOR
B	AX.25
C	PACTOR
D	802.11

12. - E2E10

Which of these digital modes has the narrowest bandwidth?

Select	Answer
A	PSK31
B	300-baud packet
C	MFSK16
D	170 Hz shift, 45-baud RTTY

13. - E3A08

When a meteor strikes the Earth's atmosphere, a cylindrical region of free electrons is formed at what layer of the ionosphere?

Select	Answer
A	The F1 layer
B	The E layer
C	The D layer
D	The F2 layer

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	Propagation across the geomagnetic equator
D	Signals reflected back toward the transmitting station

15. - E3C06

By how much does the VHF/UHF radio horizon distance exceed the geometric horizon?

Select	Answer
A	By approximately 15 percent of the distance
B	By approximately 50 percent of the distance
C	By approximately four times the distance
D	By approximately twice the distance

16. - E4A09

Which of the following is good practice when using an oscilloscope probe?

Select	Answer
A	Never use a high-impedance probe to measure a low-impedance circuit
B	Keep the signal ground connection of the probe as short as possible
C	Never use a DC-coupled probe to measure an AC circuit
D	All these choices are correct

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

18. - E4C12

Which of the following has the largest effect on an SDR receiver's dynamic range?

Select	Answer
A	RAM speed used for data storage
B	Analog-to-digital converter sample width in bits
C	CPU register width in bits
D	Anti-aliasing input filter bandwidth

19. - E4D08

What causes intermodulation in an electronic circuit?

Select	Answer
A	Positive feedback
B	Too little gain
C	Lack of neutralization
D	Nonlinear circuits or devices

20. - E4E11

What could cause local AM broadcast band signals to combine to generate spurious signals in the MF or HF bands?

Select	Answer
A	You are receiving skywave signals from a distant station
B	One or more of the broadcast stations is transmitting an over-modulated signal
C	Nearby corroded metal joints are mixing and re-radiating the broadcast signals
D	Your station receiver IF amplifier stage is defective

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

22. - E5B06

What is susceptance?

Select	Answer
A	A measure of the efficiency of a transformer
B	The imaginary part of admittance
C	The ratio of magnetic field to electric field
D	The magnetic impedance of a circuit

23. - E5C08

What coordinate system is often used to display the phase angle of a circuit containing resistance, inductive and/or capacitive reactance?

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

24. - E5D01

What is the result of skin effect?

Select	Answer
A	Thermal effects on the surface of the conductor decrease the impedance
B	Thermal effects on the surface of the conductor increase the impedance
C	As frequency increases, RF current flows in a thinner layer of the conductor, closer to the surface
D	As frequency decreases, RF current flows in a thinner layer of the conductor, closer to the surface

25. - E6A03

Why does a PN-junction diode not conduct current when reverse biased?

Select	Answer
A	Only P-type semiconductor material can conduct current
B	Only N-type semiconductor material can conduct current
C	Holes in P-type material and electrons in the N-type material are separated by the applied voltage, widening the depletion region
D	Excess holes in P-type material combine with the electrons in N-type material, converting the entire diode into an insulator

26. - E6B04

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

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

27. - E6C09

What is a Programmable Logic Device (PLD)?

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

28. - E6D04

Which materials are commonly used as a core in an inductor?

Select	Answer
A	Polystyrene and polyethylene
B	Teflon and Delrin
C	Ferrite and brass
D	Cobalt and aluminum

29. - E6E09

Which of the following component package types would be most suitable for use at frequencies above the HF range?

Select	Answer
A	Surface mount
B	TO-220
C	Axial lead
D	Radial lead

30. - E6F09

What is the efficiency of a photovoltaic cell?

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

31. - E7A06

What is a characteristic of a monostable multivibrator?

Select	Answer
A	It stores one bit of data in either a 0 or 1 state
B	It produces a continuous square wave oscillating between 1 and 0
C	It switches momentarily to the opposite binary state and then returns to its original state after a set time
D	It maintains a constant output voltage, regardless of variations in the input voltage

32. - E7B12

What type of amplifier circuit is shown in Figure E7-1?

Select	Answer
A	Emitter follower
B	Common emitter
C	Common collector
D	Common base

33. - E7C11

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

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

34. - E7D11

What is the function of the pass transistor in a linear voltage regulator circuit?

Select	Answer
A	Maintains nearly constant output impedance over a wide range of load current
B	Maintains nearly constant output voltage over a wide range of load current
C	Provides a stable input impedance over a wide range of source voltage
D	Permits a wide range of output voltage settings

35. - E7E11

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

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

36. - E7F03

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

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

37. - E7G01

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

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

38. - E7H06

Which of the following oscillator circuits are commonly used in VFOs?

Select	Answer
A	Negative feedback and balanced feedback
B	Colpitts and Hartley
C	Armstrong and deForest
D	Pierce and Zener

39. - E8A04

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

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

40. - E8B11

What is digital time division multiplexing?

Select	Answer
A	Two or more data streams share the same channel by transmitting time of transmission as the sub-carrier
B	Two or more signals are arranged to share discrete time slots of a data transmission
C	Two or more data streams are assigned to discrete sub-carriers on an FM transmitter
D	Two or more signals are quadrature modulated to increase bandwidth efficiency

41. - E8C09

Which digital code allows only one bit to change between sequential code values?

Select	Answer
A	Extended Binary Coded Decimal Interchange Code
B	Binary Coded Decimal Code
C	Gray code
D	Excess 3 code

42. - 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	Direct sequence
C	Phase compandored spread spectrum
D	Binary phase-shift keying

43. - E9A01

What is an isotropic antenna?

Select	Answer
A	A spacecraft antenna used to direct signals toward Earth
B	A grounded antenna used to measure Earth conductivity
C	A theoretical, omnidirectional antenna used as a reference for antenna gain
D	A horizontally polarized antenna used to compare Yagi antennas

44. - E9B01

In the antenna radiation pattern shown in Figure E9-1, what is the beamwidth?

Select	Answer
A	75 degrees
B	30 degrees
C	25 degrees
D	50 degrees

45. - E9C02

What is the radiation pattern of two 1/4-wavelength vertical antennas spaced 1/4 wavelength apart and fed 90 degrees out of phase?

Select	Answer
A	Omni-directional
B	A figure-8 end-fire along the axis of the array
C	A figure-8 broadside to the axis of the array
D	Cardioid

46. - E9D11

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

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

47. - E9E08

What is a use for a Wilkinson divider?

Select	Answer
A	It is used to feed high-impedance antennas from a low-impedance source
B	It is used to feed low-impedance loads from a high-impedance source
C	It divides the operating frequency of a transmitter signal so it can be used on a lower frequency band
D	It is used to divide power equally between two 50-ohm loads while maintaining 50-ohm input impedance

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

49. - E9G08

What is the process of normalization with regard to a Smith chart?

Select	Answer
A	Reassigning resistance values with regard to the reactance axis
B	Reassigning reactance values with regard to the resistance axis
C	Reassigning prime center with regard to the reactance axis
D	Reassigning impedance values with regard to the prime center

50. - E9H05

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

Select	Answer
A	It is practical for use only on VHF and higher bands
B	It has a bidirectional pattern
C	It has no clearly defined null
D	All these choices are correct

Figure E7-1

Figure E9-1