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	Mica
C	Uranium Hexafluoride
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 an isotropic radiator
B	100 watts PEP effective radiated power relative to the gain of a half-wave dipole
C	50 watts PEP effective radiated power relative to an isotropic radiator
D	50 watts PEP effective radiated power relative to a dipole

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	20 kHz
B	3 kHz
C	10 kHz
D	15 kHz

4. - E1C09

What is the highest modulation index permitted at the highest modulation frequency for angle modulation below 29.0 MHz?

Select	Answer
A	0.5
B	3.0
C	2.0
D	1.0

5. - E1D01

What is the definition of telemetry?

Select	Answer
A	One-way transmission of measurements at a distance from the measuring instrument
B	One-way transmission that initiates, modifies, or terminates the functions of a device at a distance
C	Two-way transmissions of data
D	Two-way transmissions in excess of 1000 feet

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. - E1F06

Under what circumstances might the FCC issue a Special Temporary Authority (STA) to an amateur station?

Select	Answer
A	To provide temporary operation while awaiting normal licensing
B	To allow regular operation on Land Mobile channels
C	To provide additional spectrum for personal use
D	To provide for experimental amateur communications

8. - E2A01

What is the direction of an ascending pass for an amateur satellite?

Select	Answer
A	From west to east
B	From east to west
C	From north to south
D	From south to north

9. - E2B02

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

Select	Answer
A	525
B	1080
C	30
D	60

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

11. - E2D09

What type of modulation is used for JT65 contacts?

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

12. - E2E12

How do ALE stations establish contact?

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

13. - E3A10

Which type of atmospheric structure can create a path for microwave propagation?

Select	Answer
A	The jet stream
B	Temperature inversion
C	Wind shear
D	Dust devil

14. - E3B02

What is the approximate maximum range for signals using transequatorial propagation?

Select	Answer
A	5000 miles
B	2500 miles
C	7500 miles
D	1000 miles

15. - E3C14

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

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

16. - E4A01

Which of the following limits the highest frequency signal that can be accurately displayed on a digital oscilloscope?

Select	Answer
A	All these choices are correct
B	Q of the circuit
C	Sampling rate of the analog-to-digital converter
D	Amount of memory

17. - E4B02

What is the significance of voltmeter sensitivity expressed in ohms per volt?

Select	Answer
A	When used as an ammeter, the full scale reading in amps divided by ohms per volt rating will determine the size of shunt needed
B	The full scale reading of the voltmeter multiplied by its ohms per volt rating will indicate the input impedance of the voltmeter
C	When used as a galvanometer, the reading in volts multiplied by the ohms per volt rating will determine the power drawn by the device under test
D	When used as an ohmmeter, the reading in ohms divided by the ohms per volt rating will determine the voltage applied to the circuit

18. - E4C05

What does a receiver noise floor of -174 dBm represent?

Select	Answer
A	The minimum detectable signal as a function of receive frequency
B	The theoretical noise in a 1 Hz bandwidth at the input of a perfect receiver at room temperature
C	The noise figure of a 1 Hz bandwidth receiver
D	The galactic noise contribution to minimum detectable signal

19. - E4D10

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

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

20. - E4E03

Which of the following signals might a receiver noise blanker be able to remove from desired signals?

Select	Answer
A	Signals that have a sharply peaked frequency distribution
B	Signals that appear across a wide bandwidth
C	Signals that appear at one IF but not another
D	Signals that are constant at all IF levels

21. - E5A07

What is the magnitude of the current at the input of a parallel RLC circuit at resonance?

Select	Answer
A	L/R
B	Maximum
C	Minimum
D	R/L

22. - E5B10

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

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

23. - E5C02

How are impedances described in polar coordinates?

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

24. - E5D15

What is the power factor of an RL circuit having a 45-degree phase angle between the voltage and the current?

Select	Answer
A	0.866
B	1.0
C	0.5
D	0.707

25. - E6A11

In Figure E6-1, what is the schematic symbol for a P-channel junction FET?

Select	Answer
A	1
B	6
C	2
D	3

26. - E6B10

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

Select	Answer
A	5
B	7
C	6
D	1

27. - E6C08

In Figure E6-3, what is the schematic symbol for a NAND gate?

Select	Answer
A	3
B	4
C	2
D	1

28. - E6D07

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

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

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	Radial lead
D	Axial lead

30. - E6F06

Which of these materials is most commonly used to create photoconductive devices?

Select	Answer
A	A liquid semiconductor
B	A crystalline semiconductor
C	An ordinary metal
D	A heavy metal

31. - E7A02

What is the function of a decade counter?

Select	Answer
A	It decodes a binary number for display on a seven-segment LED display
B	It produces one output pulse for every 10 input pulses
C	It decodes a decimal number for display on a seven-segment LED display
D	It produces 10 output pulses for every input pulse

32. - E7B02

What is a Class D amplifier?

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

33. - E7C08

Which of the following factors has the greatest effect on the bandwidth and response shape of a crystal ladder filter?

Select	Answer
A	The amplitude of the signals passing through the filter
B	The relative frequencies of the individual crystals
C	The gain of the RF stage preceding the filter
D	The DC voltage applied to the quartz crystal

34. - E7D07

What is the purpose of C2 in the circuit shown in Figure E7-2?

Select	Answer
A	To self-resonate at the hum frequency
B	It is a brute force filter for the output
C	It bypasses rectifier output ripple around D1
D	To provide fixed DC bias for Q1

35. - E7E02

What is the function of a reactance modulator?

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

36. - E7F06

What is the minimum number of bits required for an analog-to-digital converter to sample a signal with a range of 1 volt at a resolution of 1 millivolt?

Select	Answer
A	4 bits
B	8 bits
C	10 bits
D	6 bits

37. - E7G04

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

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

38. - E7H15

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

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

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	An error caused by irregular quantization step size
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. - E8B01

What is the modulation index of an FM signal?

Select	Answer
A	The ratio of frequency deviation to modulating signal frequency
B	The type of modulation used by the transmitter
C	The bandwidth of the transmitted signal divided by the modulating signal frequency
D	The ratio of modulating signal amplitude to frequency deviation

41. - E8C06

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

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

42. - E8D03

How does the spread spectrum technique of frequency hopping work?

Select	Answer
A	If interference is detected by the receiver it will signal the transmitter to change frequencies
B	If interference is detected by the receiver it will signal the transmitter to wait until the frequency is clear
C	A binary bit stream is used to shift the phase of an RF carrier very rapidly in a pseudorandom sequence
D	The frequency of the transmitted signal is changed very rapidly according to a pseudorandom sequence also used by the receiving station

43. - E9A01

What is an isotropic antenna?

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

44. - E9B03

In the antenna radiation pattern shown in Figure E9-1, what is the front-to-side ratio?

Select	Answer
A	12 dB
B	14 dB
C	18 dB
D	24 dB

45. - E9C06

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

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

46. - E9D03

Where should a high Q loading coil be placed to minimize losses in a shortened vertical antenna?

Select	Answer
A	At a voltage node
B	As close to the transmitter as possible
C	As low as possible on the vertical radiator
D	Near the center of the vertical radiator

47. - E9E07

What parameter describes the interactions at the load end of a mismatched transmission line?

Select	Answer
A	Reflection coefficient
B	Characteristic impedance
C	Velocity factor
D	Dielectric constant

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	4.3 meters
B	10.6 meters
C	3.5 meters
D	5.3 meters

49. - E9G04

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

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

50. - E9H02

Which is generally true for low band (160 meter and 80 meter) receiving antennas?

Select	Answer
A	Atmospheric noise is so high that gain over a dipole is not important
B	Low loss coax transmission line is essential for good performance
C	All these choices are correct
D	They must be erected at least 1/2 wavelength above the ground to attain good directivity

Figure E6-1

Figure E6-2

Figure E6-3

Figure E7-2

Figure E9-1