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

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1. - E0A07

How may dangerous levels of carbon monoxide from an emergency generator be detected?

Select	Answer
A	By the yellowish appearance of the gas
B	Any ordinary smoke detector can be used
C	By the odor
D	Only with a carbon monoxide detector

2. - E1A05

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

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

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	15 kHz
C	3 kHz
D	10 kHz

4. - E1C05

When may an automatically controlled station originate third party communications?

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

5. - E1D10

Which amateur stations are eligible to be telecommand stations of space stations (subject to the privileges of the class of operator license held by the control operator of the station)?

Select	Answer
A	All these choices are correct
B	Any amateur station so designated by the space station licensee
C	Any amateur station designated by NASA
D	Any amateur station so designated by the ITU

6. - E1E08

To which of the following examinees may a VE not administer an examination?

Select	Answer
A	Relatives of the VE as listed in the FCC rules
B	Employees of the VE
C	Friends of the VE
D	All these choices are correct

7. - E1F11

Which of the following best describes one of the standards that must be met by an external RF power amplifier if it is to qualify for a grant of FCC certification?

Select	Answer
A	It must produce full legal output when driven by not more than 5 watts of mean RF input power
B	It must satisfy the FCC's spurious emission standards when operated at the lesser of 1500 watts or its full output power
C	It must be capable of external RF switching between its input and output networks
D	It must exhibit a gain of 0 dB or less over its full output range

8. - E2A06

What are Keplerian elements?

Select	Answer
A	Parameters that define the orbit of a satellite
B	Encrypting codes used for spread spectrum modulation
C	Phase reversing elements in a Yagi antenna
D	High-emission heater filaments used in magnetron tubes

9. - E2B06

What is vestigial sideband modulation?

Select	Answer
A	Narrow-band FM modulation achieved by filtering one sideband from the audio before frequency modulating the carrier
B	Amplitude modulation in which one complete sideband and a portion of the other are transmitted
C	A type of modulation in which one sideband is inverted
D	Spread spectrum modulation achieved by applying FM modulation following single sideband amplitude modulation

10. - E2C07

What is the Cabrillo format?

Select	Answer
A	A standard for submission of electronic contest logs
B	The rules of order for meetings between contest sponsors
C	The most common set of contest rules
D	A method of exchanging information during a contest QSO

11. - E2D08

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

Select	Answer
A	Unnumbered Information
B	Acknowledgement
C	Disconnect
D	Connect

12. - E2E06

What is the most common data rate used for HF packet?

Select	Answer
A	48 baud
B	300 baud
C	1200 baud
D	110 baud

13. - E3A01

What is the approximate maximum separation measured along the surface of the Earth between two stations communicating by EME?

Select	Answer
A	5000 miles, if the moon is at perigee
B	500 miles, if the moon is at perigee
C	2000 miles, if the moon is at apogee
D	12,000 miles, if the moon is visible by both stations

14. - E3B06

Which of the following amateur bands most frequently provides long-path propagation?

Select	Answer
A	6 meters
B	20 meters
C	10 meters
D	80 meters

15. - E3C05

What orientation of Bz (B sub z) increases the likelihood that incoming particles from the sun will cause disturbed conditions?

Select	Answer
A	Eastward
B	Southward
C	Westward
D	Northward

16. - E4A05

What is the purpose of the prescaler function on a frequency counter?

Select	Answer
A	It amplifies low-level signals for more accurate counting
B	It prevents oscillation in a low-frequency counter circuit
C	It divides a higher frequency signal so a low-frequency counter can display the input frequency
D	It multiplies a higher frequency signal so a low-frequency counter can display the operating frequency

17. - E4B04

Which S parameter represents input port return loss or reflection coefficient (equivalent to VSWR)?

Select	Answer
A	S22
B	S11
C	S12
D	S21

18. - E4C11

Why can an attenuator be used to reduce receiver overload on the lower frequency HF bands with little or no impact on signal-to-noise ratio?

Select	Answer
A	Signals are attenuated separately from the noise
B	Atmospheric noise is generally greater than internally generated noise even after attenuation
C	The attenuator has a low-pass filter to increase the strength of lower frequency signals
D	The attenuator has a noise filter to suppress interference

19. - E4D01

What is meant by the blocking dynamic range of a receiver?

Select	Answer
A	The difference in dB between the noise floor and the level of an incoming signal that will cause 1 dB of gain compression
B	The minimum difference in dB between two signals which produce third-order intermodulation products greater than the noise floor
C	The difference in dB between the noise floor and the third-order intercept point
D	The minimum difference in dB between the levels of two FM signals that will cause one signal to block the other

20. - E4E02

Which of the following types of noise can often be reduced with a digital signal processing noise filter?

Select	Answer
A	Broadband white noise
B	Ignition noise
C	All these choices are correct
D	Power line noise

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	23.67 kHz
B	47.3 kHz
C	157.8 Hz
D	315.6 Hz

22. - E5B07

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 500 ohms, R is 1 kilohm, and XL is 250 ohms?

Select	Answer
A	68.2 degrees with the voltage lagging the current
B	68.2 degrees with the voltage leading the current
C	14.0 degrees with the voltage leading the current
D	14.0 degrees with the voltage lagging the current

23. - E5C06

What does the impedance 50-j25 represent?

Select	Answer
A	25 ohms resistance in series with 50 ohms capacitive reactance
B	25 ohms resistance in series with 50 ohms inductive reactance
C	50 ohms resistance in series with 25 ohms inductive reactance
D	50 ohms resistance in series with 25 ohms capacitive reactance

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	1.414
D	1.73

25. - E6A04

What is the name given to an impurity atom that adds holes to a semiconductor crystal structure?

Select	Answer
A	N-type impurity
B	Donor impurity
C	Insulator impurity
D	Acceptor impurity

26. - E6B09

What is a common use for point-contact diodes?

Select	Answer
A	As an RF detector
B	As a constant current source
C	As a high-voltage rectifier
D	As a constant voltage source

27. - E6C10

In Figure E6-3, what is the schematic symbol for a NOR gate?

Select	Answer
A	4
B	2
C	3
D	1

28. - E6D06

What core material property determines the inductance of an inductor?

Select	Answer
A	Thermal impedance
B	Reactivity
C	Resistance
D	Permeability

29. - E6E05

Which of the following noise figure values is typical of a low-noise UHF preamplifier?

Select	Answer
A	-20 dBm
B	-10 dB
C	2 dB
D	44 dBm

30. - E6F10

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

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

31. - E7A06

What is a characteristic of a monostable multivibrator?

Select	Answer
A	It stores one bit of data in either a 0 or 1 state
B	It switches momentarily to the opposite binary state and then returns to its original state after a set time
C	It produces a continuous square wave oscillating between 1 and 0
D	It maintains a constant output voltage, regardless of variations in the input voltage

32. - E7B18

What is a characteristic of a grounded-grid amplifier?

Select	Answer
A	Low bandwidth
B	High filament voltage
C	Low input impedance
D	High power gain

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

34. - E7D08

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

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

35. - E7E03

What is a frequency discriminator stage in a FM receiver?

Select	Answer
A	An automatic band-switching circuit
B	A circuit for filtering two closely adjacent signals
C	A circuit for detecting FM signals
D	An FM generator circuit

36. - E7F03

What type of digital signal processing filter is used to generate an SSB signal?

Select	Answer
A	An elliptical filter
B	A notch filter
C	An adaptive filter
D	A Hilbert-transform filter

37. - E7G08

How does the gain of an ideal operational amplifier vary with frequency?

Select	Answer
A	It decreases linearly with increasing frequency
B	It increases linearly with increasing frequency
C	It decreases logarithmically with increasing frequency
D	It does not vary with frequency

38. - E7H13

Which of the following is a technique for providing highly accurate and stable oscillators needed for microwave transmission and reception?

Select	Answer
A	Use a temperature-controlled high Q dielectric resonator
B	Use a rubidium stabilized reference oscillator
C	All these choices are correct
D	Use a GPS signal reference

39. - E8A05

What of the following instruments would be the most accurate for measuring the RMS voltage of a complex waveform?

Select	Answer
A	A grid dip meter
B	A true-RMS calculating meter
C	A D'Arsonval meter
D	An absorption wave meter

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 signals are arranged to share discrete time slots of a data transmission
D	Two or more data streams share the same channel by transmitting time of transmission as the sub-carrier

41. - E8C01

How is Forward Error Correction implemented?

Select	Answer
A	By transmitting extra data that may be used to detect and correct transmission errors
B	By transmitting a special algorithm to the receiving station along with the data characters
C	By the receiving station repeating each block of three data characters
D	By varying the frequency shift of the transmitted signal according to a predefined algorithm

42. - E8D06

What is the advantage of including parity bits in ASCII characters?

Select	Answer
A	The signal can overpower interfering signals
B	Some types of errors can be detected
C	Foreign language characters can be sent
D	Faster transmission rate

43. - E9A09

What is antenna efficiency?

Select	Answer
A	Radiation resistance divided by transmission resistance
B	Effective radiated power divided by transmitter output
C	Total resistance divided by radiation resistance
D	Radiation resistance divided by total resistance

44. - E9B08

What is the far field of an antenna?

Select	Answer
A	The region where radiated field strengths are constant
B	The region of the ionosphere where radiated power is not refracted
C	The region where the shape of the antenna pattern is independent of distance
D	The region where radiated power dissipates over a specified time period

45. - E9C12

Which of the following describes an Extended Double Zepp antenna?

Select	Answer
A	A center-fed 1.25-wavelength antenna (two 5/8-wave elements in phase)
B	A portable antenna erected using two push support poles
C	A wideband vertical antenna constructed from precisely tapered aluminum tubing
D	An end-fed folded dipole antenna

46. - E9D04

Why should an HF mobile antenna loading coil have a high ratio of reactance to resistance?

Select	Answer
A	To lower the radiation angle
B	To swamp out harmonics
C	To minimize losses
D	To minimize the Q

47. - E9E07

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

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

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	10.6 meters
B	3.5 meters
C	5.3 meters
D	4.3 meters

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	Polar axis
B	Impedance axis
C	Reactance axis
D	Prime axis

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 E6-3

Figure E7-2

Figure E9-3