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

2. - E1A03

What is the maximum legal carrier frequency on the 20 meter band for transmitting USB AFSK digital signals having a 1 kHz bandwidth?

Select	Answer
A	14.100 MHz
B	14.149 MHz
C	14.349 MHz
D	14.070 MHz

3. - E1B03

Within what distance must an amateur station protect an FCC monitoring facility from harmful interference?

Select	Answer
A	30 miles
B	10 miles
C	1 mile
D	3 miles

4. - E1C13

What notifications must be given before transmitting on the 630 meter or 2200 meter bands?

Select	Answer
A	Operators must inform the FAA of their intent to operate, giving their call sign and distance to the nearest runway
B	Operators must inform the Utilities Technology Council (UTC) of their call sign and coordinates of the station
C	A special endorsement must be requested from the FCC
D	An environmental impact statement must be filed with the Department of the Interior

5. - E1D05

What must be posted at the station location of a station being operated by telecommand on or within 50 km of the earth's surface?

Select	Answer
A	A label with the name, address, and telephone number of the control operator
B	All these choices are correct
C	A label with the name, address, and telephone number of the station licensee
D	A photocopy of the station license

6. - E1E06

Who is responsible for the proper conduct and necessary supervision during an amateur operator license examination session?

Select	Answer
A	Each administering VE
B	The VEC coordinating the session
C	The FCC
D	The VE session manager

7. - E1F09

Which of the following conditions apply when transmitting spread spectrum emissions?

Select	Answer
A	The transmitting station must be in an area regulated by the FCC or in a country that permits SS emissions
B	All these choices are correct
C	The transmission must not be used to obscure the meaning of any communication
D	A station transmitting SS emission must not cause harmful interference to other stations employing other authorized emissions

8. - E2A12

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

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

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 provides high frequency emphasis to sharpen the picture
D	Vestigial sideband reduces bandwidth while allowing for simple video detector circuitry

10. - E2C04

Which of the following frequencies are sometimes used for amateur radio mesh networks?

Select	Answer
A	Cable TV channels 41 through 43
B	The 60 meter band channel centered on 5373 kHz
C	Frequencies shared with various unlicensed wireless data services
D	HF frequencies where digital communications are permitted

11. - E2D08

What type of packet frame is used to transmit APRS beacon data?

Select	Answer
A	Acknowledgement
B	Connect
C	Disconnect
D	Unnumbered Information

12. - E2E11

What is the difference between direct FSK and audio FSK?

Select	Answer
A	Direct FSK can transmit faster baud rates
B	Direct FSK occupies less bandwidth
C	Only direct FSK can be decoded by computer
D	Direct FSK applies the data signal to the transmitter VFO, while AFSK transmits tones via phone

13. - E3A14

What is meant by circularly polarized electromagnetic waves?

Select	Answer
A	Waves with a rotating electric field
B	Waves produced by a loop antenna
C	Waves that circle the Earth
D	Waves with an electric field bent into a circular shape

14. - E3B02

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

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

15. - E3C04

What does the value of Bz (B sub Z) represent?

Select	Answer
A	Critical frequency for vertical transmissions
B	Geomagnetic field stability
C	Direction and strength of the interplanetary magnetic field
D	Duration of long-delayed echoes

16. - E4A11

How should an antenna analyzer be connected when measuring antenna resonance and feed point impedance?

Select	Answer
A	Connect the antenna feed line directly to the analyzer's connector
B	Loosely couple the antenna and a dummy load to the analyzer
C	Connect the analyzer via a high-impedance transformer to the antenna
D	Loosely couple the analyzer near the antenna base

17. - E4B10

Which of the following methods measures intermodulation distortion in an SSB transmitter?

Select	Answer
A	Modulate the transmitter using two RF signals having harmonically related frequencies and observe the RF output with a logic analyzer
B	Modulate the transmitter using two AF signals having harmonically related frequencies and observe the RF output with a peak reading wattmeter
C	Modulate the transmitter using two AF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer
D	Modulate the transmitter using two RF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer

18. - E4C06

A CW receiver with the AGC off has an equivalent input noise power density of -174 dBm/Hz. What would be the level of an unmodulated carrier input to this receiver that would yield an audio output SNR of 0 dB in a 400 Hz noise bandwidth?

Select	Answer
A	-155 dBm
B	-148 dBm
C	-174 dBm
D	-164 dBm

19. - E4D11

Why are odd-order intermodulation products, created within a receiver, of particular interest compared to other products?

Select	Answer
A	Odd-order intermodulation produces three products for every input signal within the band of interest
B	Odd-order products are an indication of poor image rejection
C	Odd-order products overload the IF filters
D	Odd-order products of two signals in the band of interest are also likely to be within the band

20. - E4E09

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

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

21. - E5A03

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

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

22. - E5B06

What is susceptance?

Select	Answer
A	The magnetic impedance of a circuit
B	A measure of the efficiency of a transformer
C	The ratio of magnetic field to electric field
D	The imaginary part of admittance

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 4
B	Point 6
C	Point 2
D	Point 5

24. - E5D12

How many watts are consumed in a circuit having a power factor of 0.2 if the input is 100 VAC at 4 amperes?

Select	Answer
A	80 watts
B	50 watts
C	2000 watts
D	400 watts

25. - E6A01

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

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

26. - E6B04

What type of semiconductor device is designed for use as a voltage-controlled capacitor?

Select	Answer
A	Zener diode
B	Tunnel diode
C	Silicon-controlled rectifier
D	Varactor diode

27. - E6C03

What is tri-state logic?

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

28. - E6D05

What is one reason for using ferrite cores rather than powdered iron in an inductor?

Select	Answer
A	Ferrite toroids are easier to use with surface mount technology
B	Ferrite toroids generally have lower initial permeability
C	Ferrite toroids generally require fewer turns to produce a given inductance value
D	Ferrite toroids generally have better temperature stability

29. - E6E06

What characteristics of the MMIC make it a popular choice for VHF through microwave circuits?

Select	Answer
A	Plate current that is controlled by a control grid
B	The ability to retrieve information from a single signal even in the presence of other strong signals
C	Nearly infinite gain, very high input impedance, and very low output impedance
D	Controlled gain, low noise figure, and constant input and output impedance over the specified frequency range

30. - E6F11

What is the approximate open-circuit voltage produced by a fully illuminated silicon photovoltaic cell?

Select	Answer
A	12 V
B	1.5 V
C	0.5 V
D	0.1 V

31. - E7A04

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

Select	Answer
A	4
B	1
C	2
D	8

32. - E7B10

In Figure E7-1, what is the purpose of R1 and R2?

Select	Answer
A	Voltage divider bias
B	Self bias
C	Feedback
D	Load resistors

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 inductors are in series between the input and output, and a capacitor is connected between the two inductors and ground
B	Two capacitors are in series between the input and output, and an inductor is connected between the two capacitors and ground
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	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

34. - E7D08

What type of circuit is shown in Figure E7-2?

Select	Answer
A	Linear voltage regulator
B	Grounded emitter amplifier
C	Monostable multivibrator
D	Switching voltage regulator

35. - E7E01

Which of the following can be used to generate FM phone emissions?

Select	Answer
A	A balanced modulator on the audio amplifier
B	A reactance modulator on the final amplifier
C	A balanced modulator on the oscillator
D	A reactance modulator on the oscillator

36. - E7F13

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

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

37. - E7G06

What is the gain-bandwidth of an operational amplifier?

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

38. - E7H14

What is a phase-locked loop circuit?

Select	Answer
A	An electronic circuit also known as a monostable multivibrator
B	An electronic servo loop consisting of a ratio detector, reactance modulator, and voltage-controlled oscillator
C	An electronic circuit consisting of a precision push-pull amplifier with a differential input
D	An electronic servo loop consisting of a phase detector, a low-pass filter, a voltage-controlled oscillator, and a stable reference oscillator

39. - E8A04

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

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

40. - E8B11

What is digital time division multiplexing?

Select	Answer
A	Two or more signals are quadrature modulated to increase bandwidth efficiency
B	Two or more data streams are assigned to discrete sub-carriers on an FM transmitter
C	Two or more data streams share the same channel by transmitting time of transmission as the sub-carrier
D	Two or more signals are arranged to share discrete time slots of a data transmission

41. - E8C07

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

Select	Answer
A	5.76 kHz
B	9.6 kHz
C	4.8 kHz
D	15.36 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	Phase compandored spread spectrum
B	Direct sequence
C	Binary phase-shift keying
D	Frequency hopping

43. - E9A12

How much gain does an antenna have compared to a 1/2-wavelength dipole when it has 6 dB gain over an isotropic antenna?

Select	Answer
A	8.15 dB
B	3.85 dB
C	2.79 dB
D	6.0 dB

44. - E9B04

What is the front-to-back ratio of the radiation pattern shown in Figure E92?

Select	Answer
A	3 dB
B	28 dB
C	38 dB
D	15 dB

45. - E9C09

Which of the following describes a G5RV antenna?

Select	Answer
A	A phased array antenna consisting of multiple loops
B	A multi-band dipole antenna fed with coax and a balun through a selected length of open wire transmission line
C	A multi-band trap antenna
D	A wide band dipole using shorted coaxial cable for the radiating elements and fed with a�4:1 balun

46. - E9D07

What is an advantage of using top loading in a shortened HF vertical antenna?

Select	Answer
A	Higher losses
B	Improved radiation efficiency
C	Lower Q
D	Greater structural strength

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

48. - E9F08

Which of the following is a significant difference between foam dielectric coaxial cable and solid dielectric cable, assuming all other parameters are the same?

Select	Answer
A	Foam dielectric has higher velocity factor
B	Foam dielectric has lower loss per unit of length
C	Foam dielectric has lower safe operating voltage limits
D	All these choices are correct

49. - E9G06

On the Smith chart shown in Figure E9-3, what is the name for the large outer circle on which the reactance arcs terminate?

Select	Answer
A	Reactance axis
B	Impedance axis
C	Polar axis
D	Prime axis

50. - E9H11

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

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

Figure E5-1

Figure E7-1

Figure E7-2

Figure E9-3