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

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1. - E0A08

What does SAR measure?

Select	Answer
A	Signal Amplification Rating
B	The rate of RF energy reflected from stationary terrain
C	Synthetic Aperture Ratio of the human body
D	The rate at which RF energy is absorbed by the body

2. - E1A12

What special operating frequency restrictions are imposed on slow scan TV transmissions?

Select	Answer
A	They are not permitted above 54 MHz
B	They are restricted to phone band segments
C	They are restricted to 7.245 MHz, 14.245 MHz, 21.345 MHz, and 28.945 MHz
D	None; they are allowed on all amateur frequencies

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

4. - E1C06

Which of the following is required in order to operate in accordance with CEPT rules in foreign countries where permitted?

Select	Answer
A	You must append "/CEPT" to your call sign
B	The U.S. embassy must approve of your operation
C	You must bring a copy of FCC Public Notice DA 16-1048
D	You must identify in the official language of the country in which you are operating

5. - E1D12

Which of the following amateur stations may transmit one-way communications?

Select	Answer
A	All these choices are correct
B	A local repeater or linked repeater station
C	A space station, beacon station, or telecommand station
D	A message forwarding station or automatically controlled digital station

6. - E1E09

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

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

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 neither the amateur nor his or her employer has a pecuniary interest in the communications
D	When transmitting international third-party communications

8. - E2A01

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

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

9. - E2B01

How many times per second is a new frame transmitted in a fast-scan (NTSC) television system?

Select	Answer
A	90
B	60
C	30
D	120

10. - E2C02

Which of the following best describes the term self-spotting? in connection with HF contest operating?

Select	Answer
A	A manual technique for rapidly zero beating or tuning to a station's frequency before calling that station
B	The often-prohibited practice of posting one's own call sign and frequency on a spotting network
C	An automatic method for rapidly zero beating or tuning to a station's frequency before calling that station
D	The acceptable practice of manually posting the call signs of stations on a spotting network

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. - E2E04

What is indicated when one of the ellipses in an FSK crossed-ellipse display suddenly disappears?

Select	Answer
A	The receiver has drifted 5 kHz from the desired receive frequency
B	The mark and space signal have been inverted
C	One of the signal filters is saturated
D	Selective fading has occurred

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

14. - E3B04

What is meant by the terms "extraordinary" and "ordinary" waves?

Select	Answer
A	Long-path and short-path waves
B	Refracted rays and reflected waves
C	Independent waves created in the ionosphere that are elliptically polarized
D	Extraordinary waves describe rare long-skip propagation compared to ordinary waves, which travel shorter distances

15. - E3C14

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

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

16. - E4A01

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

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

17. - E4B07

What do the subscripts of S parameters represent?

Select	Answer
A	The port or ports at which measurements are made
B	Frequency order of the measurements
C	Relative quality of the data
D	The relative time between measurements

18. - E4C07

What does the MDS of a receiver represent?

Select	Answer
A	The multiplex distortion stability
B	The minimum discernible signal
C	The maximum detectable spectrum
D	The meter display sensitivity

19. - E4D06

What is the term for spurious signals generated by the combination of two or more signals in a non-linear device or circuit?

Select	Answer
A	Amplifier desensitization
B	Intermodulation
C	Adjacent channel interference
D	Neutralization

20. - E4E01

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

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

21. - E5A07

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

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

22. - E5B03

How is impedance in polar form converted to an equivalent admittance?

Select	Answer
A	Take the reciprocal of the magnitude and change the sign of the angle
B	Take the reciprocal of the angle and change the sign of the magnitude
C	Take the square root of the magnitude and add 180 degrees to the angle
D	Square the magnitude and subtract 90 degrees from the angle

23. - E5C05

What is the name of the diagram used to show the phase relationship between impedances at a given frequency?

Select	Answer
A	Near field diagram
B	Phasor diagram
C	Far field diagram
D	Venn diagram

24. - E5D10

How can the true power be determined in an AC circuit where the voltage and current are out of phase?

Select	Answer
A	By dividing the reactive power by the power factor
B	By multiplying the reactive power by the power factor
C	By dividing the apparent power by the power factor
D	By multiplying the apparent power by the power factor

25. - E6A03

Why does a PN-junction diode not conduct current when reverse biased?

Select	Answer
A	Only P-type semiconductor material can conduct current
B	Excess holes in P-type material combine with the electrons in N-type material, converting the entire diode into an insulator
C	Holes in P-type material and electrons in the N-type material are separated by the applied voltage, widening the depletion region
D	Only N-type semiconductor material can conduct current

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. - E6C10

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

Select	Answer
A	3
B	2
C	4
D	1

28. - E6D05

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

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

29. - E6E06

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

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

30. - E6F07

What is a solid-state relay?

Select	Answer
A	A semiconductor passive delay line
B	A mechanical relay that latches in the on or off state each time it is pulsed
C	A device that uses semiconductors to implement the functions of an electromechanical relay
D	A relay using transistors to drive the relay coil

31. - E7A04

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

Select	Answer
A	2
B	8
C	4
D	1

32. - E7B10

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

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

33. - E7C06

What are the distinguishing features of an elliptical filter?

Select	Answer
A	Extremely flat response over its pass band with gradually rounded stop band corners
B	Extremely sharp cutoff with one or more notches in the stop band
C	Gradual passband rolloff with extreme stop band ripple
D	Gradual passband rolloff with minimal stop band ripple

34. - E7D01

How does a linear electronic voltage regulator work?

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

35. - E7E09

What occurs when an excessive amount of signal energy reaches a mixer circuit?

Select	Answer
A	A beat frequency is generated
B	Mixer blanking occurs
C	Spurious mixer products are generated
D	Automatic limiting occurs

36. - E7F02

What kind of digital signal processing audio filter is used to remove unwanted noise from a received SSB signal?

Select	Answer
A	An adaptive filter
B	A Hilbert-transform filter
C	A crystal-lattice filter
D	A phase-inverting filter

37. - E7G02

What is ringing in a filter?

Select	Answer
A	Undesired oscillations added to the desired signal
B	An echo caused by a long time delay
C	Partial cancellation of the signal over a range of frequencies
D	A reduction in high frequency response

38. - E7H11

What are the major spectral impurity components of direct digital synthesizers?

Select	Answer
A	Spurious signals at discrete frequencies
B	Digital conversion noise
C	Broadband noise
D	Nyquist limit noise

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

40. - E8B09

What is deviation ratio?

Select	Answer
A	The ratio of the audio modulating frequency to the center carrier frequency
B	The ratio of the highest audio modulating frequency to the average audio modulating frequency
C	The ratio of the carrier center frequency to the audio modulating frequency
D	The ratio of the maximum carrier frequency deviation to the highest audio modulating frequency

41. - E8C10

How may data rate be increased without increasing bandwidth?

Select	Answer
A	Using a more efficient digital code
B	Increasing analog-to-digital conversion resolution
C	It is impossible
D	Using forward error correction

42. - E8D07

What is a common cause of overmodulation of AFSK signals?

Select	Answer
A	Ground loops
B	Bit errors in the modem
C	Excessive transmit audio levels
D	Excessive numbers of retries

43. - E9A03

What is the radiation resistance of an antenna?

Select	Answer
A	The specific impedance of the antenna
B	The combined losses of the antenna elements and feed line
C	The value of a resistance that would dissipate the same amount of power as that radiated from an antenna
D	The resistance in the atmosphere that an antenna must overcome to be able to radiate a signal

44. - E9B06

What is the elevation angle of peak response in the antenna radiation pattern shown in Figure E9-2?

Select	Answer
A	25 degrees
B	7.5 degrees
C	75 degrees
D	45 degrees

45. - E9C09

Which of the following describes a G5RV antenna?

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

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	Greater structural strength
D	Lower Q

47. - E9E01

What system matches a higher-impedance transmission line to a lower-impedance antenna by connecting the line to the driven element in two places spaced a fraction of a wavelength each side of element center?

Select	Answer
A	The stub matching system
B	The gamma matching system
C	The omega matching system
D	The delta matching system

48. - E9F04

What impedance does a 1/2-wavelength transmission line present to a generator when the line is shorted at the far end?

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

49. - E9G07

On the Smith chart shown in Figure E9-3, what is the only straight line shown?

Select	Answer
A	The resistance axis
B	The voltage axis
C	The reactance axis
D	The current axis

50. - E9H11

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

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

Figure E6-2

Figure E6-3

Figure E7-1

Figure E9-2

Figure E9-3