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

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1. - E0A11

Which of the following injuries can result from using high-power UHF or microwave transmitters?

Select	Answer
A	Ingestion of ozone gas from the cooling system
B	Blood clotting from the intense magnetic field
C	Hearing loss caused by high voltage corona discharge
D	Localized heating of the body from RF exposure in excess of the MPE limits

2. - E1A04

With your transceiver displaying the carrier frequency of phone signals, you hear a DX station calling CQ on 3.601 MHz LSB. Is it legal to return the call using lower sideband on the same frequency?

Select	Answer
A	No, U.S. stations are not permitted to use phone emissions below 3.610 MHz
B	Yes, because the DX station initiated the contact
C	Yes, because the displayed frequency is within the 75 meter phone band segment
D	No, the sideband will extend beyond the edge of the phone band segment

3. - E1B08

What limitations may the FCC place on an amateur station if its signal causes interference to domestic broadcast reception, assuming that the receivers involved are of good engineering design?

Select	Answer
A	The amateur station must cease operation on all frequencies above 30 MHz
B	The amateur station must avoid transmitting during certain hours on frequencies that cause the interference
C	The amateur station must cease operation on all frequencies below 30 MHz
D	The amateur station must cease operation

4. - E1C12

On what portion of the 630 meter band are phone emissions permitted?

Select	Answer
A	Only the top 3 kHz
B	Only the bottom 3 kHz
C	The entire band
D	None

5. - E1D06

What is the maximum permitted transmitter output power when operating a model craft by telecommand?

Select	Answer
A	1 watt
B	5 watts
C	2 watts
D	100 watts

6. - E1E09

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

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

7. - E1F07

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

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

8. - E2A07

Which of the following types of signals can be relayed through a linear transponder?

Select	Answer
A	SSB and SSTV
B	FM and CW
C	All these choices are correct
D	PSK and packet

9. - E2B05

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

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

10. - E2C12

What technique do individual nodes use to form a mesh network?

Select	Answer
A	Forward error correction and Viterbi codes
B	Custom code plugs for the local trunking systems
C	Acting as store-and-forward digipeaters
D	Discovery and link establishment protocols

11. - E2D01

Which of the following digital modes is designed for meteor scatter communications?

Select	Answer
A	APRS
B	WSPR
C	MSK144
D	Hellschreiber

12. - E2E10

Which of these digital modes has the narrowest bandwidth?

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

13. - E3A06

What might help to restore contact when DX signals become too weak to copy across an entire HF band a few hours after sunset?

Select	Answer
A	Wait 90 minutes or so for the signal degradation to pass
B	Switch to a lower frequency HF band
C	Switch to a higher frequency HF band
D	Wait 24 hours before attempting another communication on the band

14. - E3B11

At what time of day can sporadic E propagation occur?

Select	Answer
A	Only around sunset
B	Only in hours of darkness
C	Only around sunset and sunrise
D	Any time

15. - E3C08

What does the space weather term G5 mean?

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

16. - E4A10

Which of the following displays multiple digital signal states simultaneously?

Select	Answer
A	Modulation monitor
B	Bit error rate tester
C	Network analyzer
D	Logic analyzer

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	When used as an ohmmeter, the reading in ohms divided by the ohms per volt rating will determine the voltage applied to the circuit
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	The full scale reading of the voltmeter multiplied by its ohms per volt rating will indicate the input impedance of the voltmeter

18. - E4C05

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

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

19. - E4D09

What is the purpose of the preselector in a communications receiver?

Select	Answer
A	To store often-used frequencies
B	To increase rejection of signals outside the desired band
C	To provide a range of AGC time constants
D	To allow selection of the optimum RF amplifier device

20. - E4E01

What problem can occur when using an automatic notch filter (ANF) to remove interfering carriers while receiving CW signals?

Select	Answer
A	Received CW signals will appear to be modulated at the DSP clock frequency
B	Any nearby signal passing through the DSP system will overwhelm the desired signal
C	Removal of the CW signal as well as the interfering carrier
D	Ringing in the DSP filter will completely remove the spaces between the CW characters

21. - E5A11

What is the half-power bandwidth of a resonant circuit that has a resonant frequency of 7.1 MHz and a Q of 150?

Select	Answer
A	47.3 kHz
B	157.8 Hz
C	315.6 Hz
D	23.67 kHz

22. - E5B02

What letter is commonly used to represent susceptance?

Select	Answer
A	B
B	X
C	G
D	Y

23. - E5C10

Which point on Figure E5-1 best represents the impedance of a series circuit consisting of a 400-ohm resistor and a 38-picofarad capacitor at 14 MHz?

Select	Answer
A	Point 6
B	Point 4
C	Point 2
D	Point 5

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	141.4 watts
B	100 watts
C	200 watts
D	70.7 watts

25. - E6A01

In what application is gallium arsenide used as a semiconductor material?

Select	Answer
A	In microwave circuits
B	In high-current rectifier circuits
C	In very low-frequency RF circuits
D	In high-power audio circuits

26. - E6B05

What characteristic of a PIN diode makes it useful as an RF switch?

Select	Answer
A	Extremely high reverse breakdown voltage
B	Ability to dissipate large amounts of power
C	Low junction capacitance
D	Reverse bias controls its forward voltage drop

27. - E6C05

What is an advantage of CMOS logic devices over TTL devices?

Select	Answer
A	Differential output capability
B	Immune to damage from static discharge
C	Lower distortion
D	Lower power consumption

28. - E6D11

Which type of core material decreases inductance when inserted into a coil?

Select	Answer
A	Ferrite
B	Ceramic
C	Brass
D	Powdered iron

29. - E6E04

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

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

30. - E6F10

What is the most common type of photovoltaic cell used for electrical power generation?

Select	Answer
A	Selenium
B	Cadmium Sulfide
C	Copper oxide
D	Silicon

31. - E7A08

What logical operation does an OR gate perform?

Select	Answer
A	It produces logic 0 at its output if all inputs are logic 1
B	It produces logic 1 at its output if any or all inputs are logic 1
C	It only produces logic 0 at its output when all inputs are logic 1
D	It produces logic 1 at its output if all inputs are logic 0

32. - E7B01

For what portion of the signal cycle does each active element in a push-pull Class AB amplifier conduct?

Select	Answer
A	Exactly 180 degrees
B	Less than 180 degrees
C	More than 180 degrees but less than 360 degrees
D	The entire cycle

33. - E7C11

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

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

34. - E7D14

What is the purpose of connecting equal-value resistors across power supply filter capacitors connected in series?

Select	Answer
A	Equalize the voltage across each capacitor
B	Discharge the capacitors when voltage is removed
C	Provide a minimum load on the supply
D	All these choices are correct

35. - E7E02

What is the function of a reactance modulator?

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

36. - E7F10

What aspect of receiver analog-to-digital conversion determines the maximum receive bandwidth of a Direct Digital Conversion SDR?

Select	Answer
A	Sample clock phase noise
B	Sample rate
C	Processor latency
D	Sample width in bits

37. - E7G11

What absolute voltage gain can be expected from the circuit in Figure E7-3 when R1 is 3300 ohms and RF is 47 kilohms?

Select	Answer
A	14
B	7
C	0.07
D	28

38. - E7H09

What type of frequency synthesizer circuit uses a phase accumulator, lookup table, digital to analog converter, and a low-pass anti-alias filter?

Select	Answer
A	A phase-locked loop synthesizer
B	A hybrid synthesizer
C	A direct digital synthesizer
D	A diode-switching matrix synthesizer

39. - E8A06

What is the approximate ratio of PEP-to-average power in a typical single-sideband phone signal?

Select	Answer
A	1 to 1
B	100 to 1
C	2.5 to 1
D	25 to 1

40. - E8B03

What is the modulation index of an FM-phone signal having a maximum frequency deviation of 3000 Hz either side of the carrier frequency when the modulating frequency is 1000 Hz?

Select	Answer
A	1000
B	0.3
C	3
D	3000

41. - E8C05

What is the approximate bandwidth of a 13-WPM International Morse Code transmission?

Select	Answer
A	104 Hz
B	52 Hz
C	26 Hz
D	13 Hz

42. - E8D09

What is considered an acceptable maximum IMD level for an idling PSK signal?

Select	Answer
A	+15 dB
B	+10 dB
C	-30 dB
D	-20 dB

43. - E9A11

Which of the following factors determines ground losses for a ground-mounted vertical antenna operating in the 3 MHz to 30 MHz range?

Select	Answer
A	Soil conductivity
B	Take-off angle
C	The standing wave ratio
D	Distance from the transmitter

44. - E9B03

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

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

45. - E9C07

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

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

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	Wide flat copper strap
C	Solid wire
D	Resistive wire, such as spark plug wire

47. - E9E10

Which of these choices is an effective way to match an antenna with a 100-ohm feed point impedance to a 50-ohm coaxial cable feed line?

Select	Answer
A	Insert a 1/4-wavelength piece of 75-ohm coaxial cable transmission line in series between the antenna terminals and the 50-ohm feed cable
B	Connect a 1/2 wavelength shorted stub of 75-ohm cable in parallel with the 50-ohm cable where it attaches to the antenna
C	Connect a 1/4-wavelength open stub of 300-ohm twinlead in parallel with the coaxial feed line where it connects to the antenna
D	Insert a 1/2 wavelength piece of 300-ohm twinlead in series between the antenna terminals and the 50-ohm feed cable

48. - E9F12

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

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

49. - E9G10

What do the arcs on a Smith chart represent?

Select	Answer
A	Points with constant resistance
B	Frequency
C	SWR
D	Points with constant reactance

50. - E9H11

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

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

Figure E5-1

Figure E7-3

Figure E9-1