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	Beryllium Oxide
B	Uranium Hexafluoride
C	Mica
D	Zinc oxide

2. - E1A05

What is the maximum power output permitted on the 60 meter band?

Select	Answer
A	100 watts PEP effective radiated power relative to the gain of a half-wave dipole
B	50 watts PEP effective radiated power relative to an isotropic radiator
C	50 watts PEP effective radiated power relative to a dipole
D	100 watts PEP effective radiated power relative to an isotropic radiator

3. - E1B07

To what type of regulations does PRB-1 apply?

Select	Answer
A	State and local zoning
B	Homeowners associations
C	FAA tower height limits
D	Use of wireless devices in vehicles

4. - E1C08

What is the maximum permissible duration of a remotely controlled station's transmissions if its control link malfunctions?

Select	Answer
A	10 minutes
B	30 seconds
C	3 minutes
D	5 minutes

5. - E1D04

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

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

6. - E1E05

What is the minimum passing score on all amateur operator license examinations?

Select	Answer
A	Minimum passing score of 77%
B	Minimum passing score of 74%
C	Minimum passing score of 70%
D	Minimum passing score of 80%

7. - E1F02

What privileges are authorized in the U.S. to persons holding an amateur service license granted by the government of Canada?

Select	Answer
A	None, they must obtain a U.S. license
B	All privileges of the Amateur Extra Class license
C	The operating terms and conditions of the Canadian amateur service license, not to exceed U.S. Amateur Extra Class license privileges
D	Full privileges, up to and including those of the Amateur Extra Class license, on the 80, 40, 20, 15, and 10 meter bands

8. - E2A04

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

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

9. - E2B05

Which of the following describes the use of vestigial sideband in analog fast-scan TV transmissions?

Select	Answer
A	The vestigial sideband contains chroma information
B	The vestigial sideband carries the audio information
C	Vestigial sideband reduces bandwidth while allowing for simple video detector circuitry
D	Vestigial sideband provides high frequency emphasis to sharpen the picture

10. - E2C06

During a VHF/UHF contest, in which band segment would you expect to find the highest level of SSB or CW activity?

Select	Answer
A	At the top of each band, usually in a segment reserved for contests
B	In the weak signal segment of the band, with most of the activity near the calling frequency
C	In the middle of the band, usually 25 kHz above the national calling frequency
D	In the middle of each band, usually on the national calling frequency

11. - E2D10

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

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

12. - E2E12

How do ALE stations establish contact?

Select	Answer
A	ALE radios send a constant tone code to establish a frequency for future use
B	ALE constantly scans a list of frequencies, activating the radio when the designated call sign is received
C	ALE radios activate when they hear their signal echoed by back scatter
D	ALE radios monitor an internet site for the frequency they are being paged on

13. - E3A03

When scheduling EME contacts, which of these conditions will generally result in the least path loss?

Select	Answer
A	When the moon is at perigee
B	When the MUF is above 30 MHz
C	When the moon is full
D	When the moon is at apogee

14. - E3B09

At what time of year is sporadic E propagation most likely to occur?

Select	Answer
A	Around the solstices, especially the summer solstice
B	Around the solstices, especially the winter solstice
C	Around the equinoxes, especially the spring equinox
D	Around the equinoxes, especially the fall equinox

15. - E3C09

How does the intensity of an X3 flare compare to that of an X2 flare?

Select	Answer
A	10 percent greater
B	50 percent greater
C	Four times as great
D	Twice as great

16. - E4A02

Which of the following parameters does a spectrum analyzer display on the vertical and horizontal axes?

Select	Answer
A	SWR and frequency
B	RF amplitude and frequency
C	SWR and time
D	RF amplitude and time

17. - E4B11

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

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

18. - E4C01

What is an effect of excessive phase noise in a receiver's local oscillator?

Select	Answer
A	It limits the receiver's ability to receive strong signals
B	It can combine with strong signals on nearby frequencies to generate interference
C	It can affect the receiver's frequency calibration
D	It decreases receiver third-order intercept point

19. - E4D10

What does a third-order intercept level of 40 dBm mean with respect to receiver performance?

Select	Answer
A	Signals less than 40 dBm will not generate audible third-order intermodulation products
B	A pair of 40 dBm input signals will theoretically generate a third-order intermodulation product that has the same output amplitude as either of the input signals
C	A pair of 1 mW input signals will produce a third-order intermodulation product that is 40 dB stronger than the input signal
D	The receiver can tolerate signals up to 40 dB above the noise floor without producing third-order intermodulation products

20. - E4E04

How can conducted and radiated noise caused by an automobile alternator be suppressed?

Select	Answer
A	By installing filter capacitors in series with the DC power lead and a blocking capacitor in the field lead
B	By connecting the radio's power leads directly to the battery and by installing coaxial capacitors in line with the alternator leads
C	By installing a high-pass filter in series with the radio's power lead and a low-pass filter in parallel with the field lead
D	By installing a noise suppression resistor and a blocking capacitor in both leads

21. - E5A03

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

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

22. - E5B10

What is the relationship between the AC current through an inductor and the voltage across an inductor?

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

23. - E5C11

Which point in Figure E5-1 best represents the impedance of a series circuit consisting of a 300-ohm resistor and an 18-microhenry inductor at 3.505 MHz?

Select	Answer
A	Point 8
B	Point 1
C	Point 3
D	Point 7

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	70.7 watts
B	141.4 watts
C	200 watts
D	100 watts

25. - E6A10

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

Select	Answer
A	2
B	5
C	6
D	4

26. - E6B03

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

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

27. - E6C06

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

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

28. - E6D07

What is current in the primary winding of a transformer called if no load is attached to the secondary?

Select	Answer
A	Stabilizing current
B	Magnetizing current
C	Direct current
D	Excitation current

29. - E6E04

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

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

30. - E6F04

What is the photovoltaic effect?

Select	Answer
A	The tendency of a battery to discharge when exposed to light
B	The conversion of electrical energy to mechanical energy
C	The conversion of light to electrical energy
D	The conversion of voltage to current when exposed to light

31. - E7A04

How many flip-flops are required to divide a signal frequency by 4?

Select	Answer
A	2
B	8
C	1
D	4

32. - E7B15

What is one way to prevent thermal runaway in a bipolar transistor amplifier?

Select	Answer
A	Use a resistor in series with the emitter
B	Select transistors with high beta
C	Neutralization
D	All these choices are correct

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

34. - E7D01

How does a linear electronic voltage regulator work?

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

35. - E7E02

What is the function of a reactance modulator?

Select	Answer
A	To produce AM signals by using an electrically variable resistance
B	To produce PM signals by using an electrically variable resistance
C	To produce AM signals by using an electrically variable inductance or capacitance
D	To produce PM or FM signals by using an electrically variable inductance or capacitance

36. - E7F13

What is the function of taps in a digital signal processing filter?

Select	Answer
A	Select the point at which baseband signals are generated
B	To reduce excess signal pressure levels
C	Provide access for debugging software
D	Provide incremental signal delays for filter algorithms

37. - E7G04

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

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

38. - E7H03

How is positive feedback supplied in a Hartley oscillator?

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

39. - E8A04

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

Select	Answer
A	An abnormal condition where the converter cannot settle on a value to represent the signal
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	A method of decimation by randomly skipping samples

40. - E8B04

What is the modulation index of an FM-phone signal having a maximum carrier deviation of plus or minus 6 kHz when modulated with a 2 kHz modulating frequency?

Select	Answer
A	6000
B	3
C	2000
D	1/3

41. - E8C07

What is the bandwidth of a 4800-Hz frequency shift, 9600-baud ASCII FM transmission?

Select	Answer
A	15.36 kHz
B	9.6 kHz
C	4.8 kHz
D	5.76 kHz

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	Direct sequence
B	Binary phase-shift keying
C	Phase compandored spread spectrum
D	Frequency hopping

43. - E9A08

What is antenna bandwidth?

Select	Answer
A	The angle formed between two imaginary lines drawn through the element ends
B	Antenna length divided by the number of elements
C	The frequency range over which an antenna satisfies a performance requirement
D	The angle between the half-power radiation points

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. - E9C07

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

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

46. - E9D01

How much does the gain of an ideal parabolic dish antenna change when the operating frequency is doubled?

Select	Answer
A	6 dB
B	2 dB
C	3 dB
D	4 dB

47. - E9E05

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

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

48. - E9F02

Which of the following has the biggest effect on the velocity factor of a transmission line?

Select	Answer
A	The center conductor resistivity
B	The termination impedance
C	The line length
D	Dielectric materials used in the line

49. - E9G02

What type of coordinate system is used in a Smith chart?

Select	Answer
A	Resistance lines and reactance chords
B	Resistance circles and reactance arcs
C	Voltage lines and current chords
D	Voltage circles and current arcs

50. - E9H03

What is Receiving Directivity Factor (RDF)?

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

Figure E5-1

Figure E6-1

Figure E9-1