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

Logging in (or registering) will help the system to select questions that you need to focus on.

1. - E0A08

What does SAR measure?

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

2. - 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 originating station
B	The control operators of all the stations in the system
C	The control operators of all the stations in the system not authenticating the source from which they accept communications
D	The control operator of the packet bulletin board station

3. - E1B02

Which of the following is an acceptable bandwidth for Digital Radio Mondiale (DRM) based voice or SSTV digital transmissions made on the HF amateur bands?

Select	Answer
A	10 kHz
B	15 kHz
C	3 kHz
D	20 kHz

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 not operate until a test signal has been transmitted in coordination with the local power company
B	Operators must not operate until approval is received
C	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
D	Operations may commence immediately, and may continue unless interference is reported by the UTC

5. - E1D07

Which HF amateur bands have frequencies authorized for space stations?

Select	Answer
A	Only the 40, 20, 17, 15, 12, and 10 meter bands
B	All HF bands
C	Only the 40, 30, 20, 15, 12, and 10 meter bands
D	Only the 40, 20, 17, 15, and 10 meter bands

6. - E1E08

To which of the following examinees may a VE not administer an examination?

Select	Answer
A	Employees of the VE
B	Friends of the VE
C	All these choices are correct
D	Relatives of the VE as listed in the FCC rules

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

8. - E2A04

What is meant by the term mode? as applied to an amateur radio satellite?

Select	Answer
A	Whether the satellite is in a polar or equatorial orbit
B	The satellite's uplink and downlink frequency bands
C	The satellite's orientation with respect to the Earth
D	Whether the satellite is in a low earth or geostationary orbit

9. - E2B09

What hardware, other than a receiver with SSB capability and a suitable computer, is needed to decode SSTV using Digital Radio Mondiale (DRM)?

Select	Answer
A	No other hardware is needed
B	A special notch filter to remove synchronization pulses
C	A special front end limiter
D	A special IF converter

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

11. - E2D09

What type of modulation is used for JT65 contacts?

Select	Answer
A	RTTY
B	IEEE 802.11
C	Multi-tone AFSK
D	PSK

12. - E2E03

How is the timing of FT4 contacts organized?

Select	Answer
A	Stations take turns on alternate days
B	It depends on the lunar phase
C	Alternating transmissions at 7.5 second intervals
D	By exchanging ACK/NAK packets

13. - E3A13

Which of these emission modes is best for auroral propagation?

Select	Answer
A	SSB
B	RTTY
C	FM
D	CW

14. - E3B03

What is the best time of day for transequatorial propagation?

Select	Answer
A	Morning
B	Noon
C	Afternoon or early evening
D	Late at night

15. - E3C08

What does the space weather term G5 mean?

Select	Answer
A	Very low solar activity
B	An extreme geomagnetic storm
C	Moderate solar wind
D	Waning sunspot numbers

16. - E4A07

Which of the following is an advantage of using an antenna analyzer compared to an SWR bridge to measure antenna SWR?

Select	Answer
A	Antenna analyzers automatically tune your antenna for resonance
B	All these choices are correct
C	Antenna analyzers do not need an external RF source
D	Antenna analyzers display a time-varying representation of the modulation envelope

17. - E4B05

What three test loads are used to calibrate an RF vector network analyzer?

Select	Answer
A	Short circuit, open circuit, and 50 ohms
B	Short circuit, open circuit, and resonant circuit
C	50 ohms through 1/8 wavelength, 1/4 wavelength, and 1/2 wavelength of coaxial cable
D	50 ohms, 75 ohms, and 90 ohms

18. - E4C15

What is reciprocal mixing?

Select	Answer
A	Two out-of-band signals mixing to generate an in-band spurious signal
B	In-phase signals cancelling in a mixer resulting in loss of receiver sensitivity
C	Two digital signals combining from alternate time slots
D	Local oscillator phase noise mixing with adjacent strong signals to create interference to desired signals

19. - E4D08

What causes intermodulation in an electronic circuit?

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

20. - E4E06

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

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

21. - E5A10

How is the Q of an RLC series resonant circuit calculated?

Select	Answer
A	Reactance of either the inductance or capacitance divided by the resistance
B	Reactance of either the inductance or capacitance multiplied by the resistance
C	Reactance of the inductance multiplied by the reactance of the capacitance
D	Resistance divided by the reactance of either the inductance or capacitance

22. - E5B02

What letter is commonly used to represent susceptance?

Select	Answer
A	Y
B	B
C	G
D	X

23. - E5C06

What does the impedance 50-j25 represent?

Select	Answer
A	50 ohms resistance in series with 25 ohms inductive reactance
B	50 ohms resistance in series with 25 ohms capacitive reactance
C	25 ohms resistance in series with 50 ohms capacitive reactance
D	25 ohms resistance in series with 50 ohms inductive reactance

24. - E5D02

Why is it important to keep lead lengths short for components used in circuits for VHF and above?

Select	Answer
A	To maintain component lifetime
B	To increase the thermal time constant
C	To avoid unwanted inductive reactance
D	All these choices are correct

25. - E6A07

Which of the following indicates that a silicon NPN junction transistor is biased on?

Select	Answer
A	Base-to-emitter resistance of approximately 6 to 7 ohms
B	Base-to-emitter voltage of approximately 0.6 to 0.7 volts
C	Base-to-emitter voltage of approximately 6 to 7 volts
D	Base-to-emitter resistance of approximately 0.6 to 0.7 ohms

26. - E6B10

In Figure E6-2, what is the schematic symbol for a light-emitting diode?

Select	Answer
A	7
B	5
C	1
D	6

27. - E6C04

Which of the following is an advantage of BiCMOS logic?

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

28. - E6D03

Which of the following is an aspect of the piezoelectric effect?

Select	Answer
A	Mechanical deformation of material by the application of a voltage
B	Increased conductivity in the presence of light
C	Mechanical deformation of material by the application of a magnetic field
D	Generation of electrical energy in the presence of light

29. - E6E03

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

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

30. - E6F01

What absorbs the energy from light falling on a photovoltaic cell?

Select	Answer
A	Electrons
B	Protons
C	Holes
D	Photons

31. - E7A07

What logical operation does a NAND gate perform?

Select	Answer
A	It produces logic 0 at its output if some but not all inputs are logic 1
B	It produces logic 1 at its output only when all inputs are logic 1
C	It produces logic 0 at its output only when all inputs are logic 1
D	It produces logic 0 at its output only when all inputs are logic 0

32. - E7B02

What is a Class D amplifier?

Select	Answer
A	A type of amplifier that uses switching technology to achieve high efficiency
B	A low power amplifier that uses a differential amplifier for improved linearity
C	An amplifier that uses drift-mode FETs for high efficiency
D	A frequency doubling amplifier

33. - E7C01

How are the capacitors and inductors of a low-pass filter Pi-network arranged between the network's input and output?

Select	Answer
A	Two capacitors are in series between the input and output, and an inductor is connected between the two capacitors and ground
B	An inductor is connected between the input and ground, another inductor is connected between the output and ground, and a capacitor is connected between the input and output
C	A capacitor is connected between the input and ground, another capacitor is connected between the output and ground, and an inductor is connected between input and output
D	Two inductors are in series between the input and output, and a capacitor is connected between the two inductors and ground

34. - E7D01

How does a linear electronic voltage regulator work?

Select	Answer
A	The conduction of a control element is varied to maintain a constant output voltage
B	It has a ramp voltage as its output
C	It eliminates the need for a pass transistor
D	The control element duty cycle is proportional to the line or load conditions

35. - E7E06

Why is de-emphasis commonly used in FM communications receivers?

Select	Answer
A	To remove third-order distortion products
B	For higher efficiency
C	For compatibility with transmitters using phase modulation
D	To reduce impulse noise reception

36. - E7F08

What is the function of decimation?

Select	Answer
A	Converting data to binary code decimal form
B	Reducing the effective sample rate by removing samples
C	Attenuating the signal
D	Removing unnecessary significant digits

37. - E7G06

What is the gain-bandwidth of an operational amplifier?

Select	Answer
A	The maximum frequency for a filter circuit using that type of amplifier
B	The frequency at which the open-loop gain of the amplifier equals one
C	The frequency at which the amplifier's offset voltage is zero
D	The gain of the amplifier at a filter's cutoff frequency

38. - E7H12

Which of the following must be done to ensure that a crystal oscillator provides the frequency specified by the crystal manufacturer?

Select	Answer
A	Provide the crystal with a specified parallel capacitance
B	Provide the crystal with a specified parallel inductance
C	Bias the crystal at a specified voltage
D	Bias the crystal at a specified current

39. - E8A04

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

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

40. - E8B10

What is frequency division multiplexing?

Select	Answer
A	Two or more information streams are merged into a digital combiner, which then pulse position modulates the transmitter
B	The transmitted signal jumps from band to band at a predetermined rate
C	Two or more information streams are merged into a baseband, which then modulates the transmitter
D	The transmitted signal is divided into packets of information

41. - E8C01

How is Forward Error Correction implemented?

Select	Answer
A	By the receiving station repeating each block of three data characters
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 transmitting extra data that may be used to detect and correct transmission errors

42. - E8D07

What is a common cause of overmodulation of AFSK signals?

Select	Answer
A	Bit errors in the modem
B	Excessive transmit audio levels
C	Excessive numbers of retries
D	Ground loops

43. - E9A02

What is the effective radiated power relative to a dipole of a repeater station with 150 watts transmitter power output, 2 dB feed line loss, 2.2 dB duplexer loss, and 7 dBd antenna gain?

Select	Answer
A	78.7 watts
B	286 watts
C	1977 watts
D	420 watts

44. - E9B09

What type of computer program technique is commonly used for modeling antennas?

Select	Answer
A	Method of Moments
B	Calculus differentiation with respect to physical properties
C	Mutual impedance analysis
D	Graphical analysis

45. - E9C06

What is the effect of adding a terminating resistor to a rhombic antenna?

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

46. - E9D10

What happens to feed-point impedance at the base of a fixed length HF mobile antenna when operated below its resonant frequency?

Select	Answer
A	The radiation resistance decreases and the capacitive reactance increases
B	The radiation resistance increases and the capacitive reactance decreases
C	The radiation resistance increases and the capacitive reactance increases
D	The radiation resistance decreases and the capacitive reactance decreases

47. - E9E08

What is a use for a Wilkinson divider?

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

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	5.3 meters
D	3.5 meters

49. - E9G04

What are the two families of circles and arcs that make up a Smith chart?

Select	Answer
A	Reactance and voltage
B	Resistance and voltage
C	Resistance and reactance
D	Voltage and impedance

50. - E9H09

What is a Pennant antenna?

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

Figure E6-2