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

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1. - E0A09

Which insulating material commonly used as a thermal conductor for some types of electronic devices is extremely toxic if broken or crushed and the particles are accidentally inhaled?

Select	Answer
A	Uranium Hexafluoride
B	Beryllium Oxide
C	Mica
D	Zinc oxide

2. - E1A09

What action or actions should you take if your digital message forwarding station inadvertently forwards a communication that violates FCC rules?

Select	Answer
A	All these choices are correct
B	Discontinue forwarding the communication as soon as you become aware of it
C	Notify the originating station that the communication does not comply with FCC rules
D	Notify the nearest FCC Field Engineers office

3. - E1B05

What is the National Radio Quiet Zone?

Select	Answer
A	An area in Florida surrounding Cape Canaveral
B	An area in New Mexico surrounding the White Sands Test Area
C	An area in Puerto Rico surrounding the Arecibo Radio Telescope
D	An area surrounding the National Radio Astronomy Observatory

4. - E1C05

When may an automatically controlled station originate third party communications?

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

5. - E1D12

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

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

6. - E1E04

Which of the following best describes the Volunteer Examiner accreditation process?

Select	Answer
A	The procedure by which a VEC confirms that the VE applicant meets FCC requirements to serve as an examiner
B	The amateur operator applying must pass a VE examination administered by the FCC Enforcement Bureau
C	The prospective VE obtains accreditation from the FCC
D	Each General, Advanced and Amateur Extra Class operator is automatically accredited as a VE when the license is granted

7. - E1F07

When may an amateur station send a message to a business?

Select	Answer
A	When the control operator is employed by the FCC or another government agency
B	When transmitting international third-party communications
C	When neither the amateur nor his or her employer has a pecuniary interest in the communications
D	When the total money involved does not exceed $25

8. - E2A12

What is the purpose of digital store-and-forward functions on an amateur radio satellite?

Select	Answer
A	To store digital messages in the satellite for later download by other stations
B	To relay messages between satellites
C	To delay download of telemetry between satellites
D	To upload operational software for the transponder

9. - E2B01

How many times per second is a new frame transmitted in a fast-scan (NTSC) television system?

Select	Answer
A	90
B	60
C	30
D	120

10. - E2C03

From which of the following bands is amateur radio contesting generally excluded?

Select	Answer
A	2 meters
B	30 meters
C	6 meters
D	33 centimeters

11. - E2D03

Which of the following digital modes is especially useful for EME communications?

Select	Answer
A	PACTOR III
B	JT65
C	Olivia
D	MSK144

12. - E2E01

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

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

13. - E3A09

Which of the following frequency ranges is most suited for meteor scatter communications?

Select	Answer
A	220 MHz - 450 MHz
B	10 MHz - 14 MHz
C	28 MHz - 148 MHz
D	1.8 MHz - 1.9 MHz

14. - E3B01

What is transequatorial propagation?

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

15. - E3C14

Why does the radio-path horizon distance exceed the geometric horizon?

Select	Answer
A	Due to the Doppler effect
B	Downward bending due to density variations in the atmosphere
C	E-region skip
D	D-region skip

16. - E4A08

Which of the following measures SWR?

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

17. - E4B06

How much power is being absorbed by the load when a directional power meter connected between a transmitter and a terminating load reads 100 watts forward power and 25 watts reflected power?

Select	Answer
A	75 watts
B	25 watts
C	125 watts
D	100 watts

18. - E4C02

Which of the following receiver circuits can be effective in eliminating interference from strong out-of-band signals?

Select	Answer
A	A notch filter
B	A properly adjusted product detector
C	A narrow IF filter
D	A front-end filter or pre-selector

19. - E4D12

What is the term for the reduction in receiver sensitivity caused by a strong signal near the received frequency?

Select	Answer
A	Cross-modulation interference
B	Quieting
C	Squelch gain rollback
D	Desensitization

20. - E4E09

What undesirable effect can occur when using an IF noise blanker?

Select	Answer
A	The audio frequency bandwidth of the received signal might be compressed
B	FM signals can no longer be demodulated
C	Received audio in the speech range might have an echo effect
D	Nearby signals may appear to be excessively wide even if they meet emission standards

21. - E5A03

What is the magnitude of the impedance of a series RLC circuit at resonance?

Select	Answer
A	Approximately equal to circuit resistance
B	Approximately equal to capacitive reactance
C	High, as compared to the circuit resistance
D	Approximately equal to inductive reactance

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	Maidenhead grid
B	Faraday grid
C	Elliptical coordinates
D	Polar coordinates

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	0.866
B	0.5
C	1.73
D	1.414

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 keep the gate voltage within specifications and prevent the device from overheating
C	To protect the substrate from excessive voltages
D	To reduce the chance of static damage to the gate

26. - E6B06

Which of the following is a common use of a Schottky diode?

Select	Answer
A	As a rectifier in high current power supplies
B	As a variable capacitance in an automatic frequency control circuit
C	As a VHF/UHF mixer or detector
D	As a constant voltage reference in a power supply

27. - E6C03

What is tri-state logic?

Select	Answer
A	Logic devices that utilize ternary math
B	Logic devices with 0, 1, and high-impedance output states
C	Proprietary logic devices manufactured by Tri-State Devices
D	Low-power logic devices designed to operate at 3 volts

28. - E6D10

What is a primary advantage of using a toroidal core instead of a solenoidal core in an inductor?

Select	Answer
A	Toroidal cores confine most of the magnetic field within the core material
B	Toroidal cores make it easier to couple the magnetic energy into other components
C	Toroidal cores exhibit greater hysteresis
D	Toroidal cores have lower Q characteristics

29. - E6E09

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

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

30. - E6F07

What is a solid-state relay?

Select	Answer
A	A semiconductor passive delay line
B	A mechanical relay that latches in the on or off state each time it is pulsed
C	A device that uses semiconductors to implement the functions of an electromechanical relay
D	A relay using transistors to drive the relay coil

31. - E7A10

What is a truth table?

Select	Answer
A	A table of logic symbols that indicate the high logic states of an op-amp
B	A list of inputs and corresponding outputs for a digital device
C	A diagram showing logic states when the digital device output is true
D	A table of logic symbols that indicate the logic states of an op-amp

32. - E7B03

Which of the following components form the output of a class D amplifier circuit?

Select	Answer
A	A low-pass filter to remove switching signal components
B	A high-pass filter to compensate for low gain at low frequencies
C	A temperature compensating load resistor to improve linearity
D	A matched load resistor to prevent damage by switching transients

33. - E7C07

Which describes a Pi-L-network used for matching a vacuum tube final amplifier to a 50-ohm unbalanced output?

Select	Answer
A	A Pi-network with an additional series inductor on the output
B	A Phase Inverter Load network
C	A matching network in which all components are isolated from ground
D	A network with only three discrete parts

34. - E7D06

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

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

35. - E7E04

What is one way a single-sideband phone signal can be generated?

Select	Answer
A	By using a reactance modulator followed by a mixer
B	By using a balanced modulator followed by a filter
C	By using a loop modulator followed by a mixer
D	By driving a product detector with a DSB signal

36. - E7F14

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

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

37. - E7G01

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

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

38. - E7H11

What are the major spectral impurity components of direct digital synthesizers?

Select	Answer
A	Broadband noise
B	Nyquist limit noise
C	Spurious signals at discrete frequencies
D	Digital conversion noise

39. - E8A08

Why would a direct or flash conversion analog-to-digital converter be useful for a software defined radio?

Select	Answer
A	All these choices are correct
B	Immunity to out-of-sequence coding reduces spurious responses
C	Very low power consumption decreases frequency drift
D	Very high speed allows digitizing high frequencies

40. - E8B07

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

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

41. - E8C06

What is the bandwidth of a 170-hertz shift, 300-baud ASCII transmission?

Select	Answer
A	0.3 kHz
B	1.0 kHz
C	0.5 kHz
D	0.1 Hz

42. - E8D04

What is the primary effect of extremely short rise or fall time on a CW signal?

Select	Answer
A	The generation of RF harmonics
B	The generation of key clicks
C	More difficult to copy
D	Limits data speed

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	420 watts
C	1977 watts
D	286 watts

44. - E9B09

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

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

45. - E9C07

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

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

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

47. - E9E05

How must an antenna's driven element be tuned to use a hairpin matching system?

Select	Answer
A	The driven element resonance must be lower than the operating frequency
B	The driven element reactance must be inductive
C	The driven element radiation resistance must be higher than the characteristic impedance of the transmission line
D	The driven element reactance must be capacitive

48. - E9F13

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

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

49. - E9G11

How are the wavelength scales on a Smith chart calibrated?

Select	Answer
A	In fractions of antenna electrical frequency
B	In fractions of antenna electrical wavelength
C	In fractions of transmission line electrical wavelength
D	In fractions of transmission line electrical frequency

50. - E9H11

What feature of a cardioid pattern antenna makes it useful for direction finding?

Select	Answer
A	High radiation angle
B	A very sharp single null
C	Broadband response
D	A very sharp peak

Figure E7-2