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

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1. - E0A10

What toxic material may be present in some electronic components such as high voltage capacitors and transformers?

Select	Answer
A	Polytetrafluoroethylene
B	Polyethylene
C	Polychlorinated biphenyls
D	Polymorphic silicon

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

3. - E1B05

What is the National Radio Quiet Zone?

Select	Answer
A	An area in Florida surrounding Cape Canaveral
B	An area in New Mexico surrounding the White Sands Test Area
C	An area in Puerto Rico surrounding the Arecibo Radio Telescope
D	An area surrounding the National Radio Astronomy Observatory

4. - E1C05

When may an automatically controlled station originate third party communications?

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

5. - E1D08

Which VHF amateur bands have frequencies authorized for space stations?

Select	Answer
A	6 meters and 2 meters
B	2 meters and 1.25 meters
C	2 meters
D	6 meters, 2 meters, and 1.25 meters

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 VE session manager
D	The FCC

7. - E1F05

Amateur stations may not transmit in which of the following frequency segments if they are located in the contiguous 48 states and north of Line A?

Select	Answer
A	53 MHz - 54 MHz
B	222 MHz - 223 MHz
C	440 MHz - 450 MHz
D	420 MHz - 430 MHz

8. - E2A05

What do the letters in a satellite's mode designator specify?

Select	Answer
A	The uplink and downlink frequency ranges
B	The location of the ground control station
C	The polarization of uplink and downlink signals
D	Power limits for uplink and downlink transmissions

9. - E2B02

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

Select	Answer
A	1080
B	525
C	60
D	30

10. - E2C06

During a VHF/UHF contest, in which band segment would you expect to find the highest level of SSB or CW activity?

Select	Answer
A	In the middle of each band, usually on the national calling frequency
B	In the weak signal segment of the band, with most of the activity near the calling frequency
C	At the top of each band, usually in a segment reserved for contests
D	In the middle of the band, usually 25 kHz above the national calling frequency

11. - E2D06

Which of the following describes a method of establishing EME contacts?

Select	Answer
A	Time synchronous transmissions alternately from each station
B	High-speed CW identification to avoid fading
C	Judging optimum transmission times by monitoring beacons reflected from the moon
D	Storing and forwarding digital messages

12. - E2E11

What is the difference between direct FSK and audio FSK?

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

13. - E3A01

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

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

14. - E3B07

What happens to linearly polarized radio waves that split into ordinary and extraordinary waves in the ionosphere?

Select	Answer
A	They become depolarized
B	They become elliptically polarized
C	They become phase locked
D	They are bent toward the magnetic poles

15. - E3C08

What does the space weather term G5 mean?

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

16. - E4A02

Which of the following parameters does a spectrum analyzer display on the vertical and horizontal axes?

Select	Answer
A	SWR and frequency
B	RF amplitude and frequency
C	SWR and time
D	RF amplitude and time

17. - E4B11

Which of the following can be measured with a vector network analyzer?

Select	Answer
A	Reflection coefficient
B	All these choices are correct
C	Output impedance
D	Input impedance

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	-148 dBm
B	-174 dBm
C	-164 dBm
D	-155 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 products are an indication of poor image rejection
B	Odd-order products of two signals in the band of interest are also likely to be within the band
C	Odd-order products overload the IF filters
D	Odd-order intermodulation produces three products for every input signal within the band of interest

20. - E4E07

Which of the following can cause shielded cables to radiate or receive interference?

Select	Answer
A	Tying all ground connections to a common point resulting in differential-mode currents in the shield
B	Use of braided shielding material
C	Common-mode currents on the shield and conductors
D	Low inductance ground connections at both ends of the shield

21. - E5A10

How is the Q of an RLC series resonant circuit calculated?

Select	Answer
A	Reactance of either the inductance or capacitance multiplied by the resistance
B	Resistance divided by the reactance of either the inductance or capacitance
C	Reactance of the inductance multiplied by the reactance of the capacitance
D	Reactance of either the inductance or capacitance divided by the resistance

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	14.0 degrees with the voltage lagging the current
C	68.2 degrees with the voltage leading the current
D	14.0 degrees with the voltage leading the current

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 2
C	Point 4
D	Point 5

24. - E5D09

What happens to reactive power in an AC circuit that has both ideal inductors and ideal capacitors?

Select	Answer
A	It is dissipated in the formation of inductive and capacitive fields
B	It is repeatedly exchanged between the associated magnetic and electric fields, but is not dissipated
C	It is dissipated as kinetic energy in the circuit
D	It is dissipated as heat in the circuit

25. - E6A04

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

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

26. - E6B05

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

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

27. - E6C04

Which of the following is an advantage of BiCMOS logic?

Select	Answer
A	Its simplicity results in much less expensive devices than standard CMOS
B	All these choices are correct
C	It is immune to electrostatic damage
D	It has the high input impedance of CMOS and the low output impedance of bipolar transistors

28. - E6D07

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

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

29. - E6E10

What advantage does surface-mount technology offer at RF compared to using through-hole components?

Select	Answer
A	All these choices are correct
B	Components have less parasitic inductance and capacitance
C	Smaller circuit area
D	Shorter circuit-board traces

30. - E6F03

What is the most common configuration of an optoisolator or optocoupler?

Select	Answer
A	A frequency modulated helium-neon laser
B	A lens and a photomultiplier
C	An LED and a phototransistor
D	An amplitude modulated helium-neon laser

31. - E7A02

What is the function of a decade counter?

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

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

34. - E7D11

What is the function of the pass transistor in a linear voltage regulator circuit?

Select	Answer
A	Maintains nearly constant output impedance over a wide range of load current
B	Provides a stable input impedance over a wide range of source voltage
C	Permits a wide range of output voltage settings
D	Maintains nearly constant output voltage over a wide range of load current

35. - E7E10

How does a diode envelope detector function?

Select	Answer
A	By mixing signals with noise in the transition region of the diode
B	By breakdown of the Zener voltage
C	By sensing the change of reactance in the diode with respect to frequency
D	By rectification and filtering of RF signals

36. - E7F09

Why is an anti-aliasing digital filter required in a digital decimator?

Select	Answer
A	It removes low-frequency signal components to eliminate the need for DC restoration
B	It removes high-frequency signal components that would otherwise be reproduced as lower frequency components
C	It notches out the sampling frequency to avoid sampling errors
D	It peaks the response of the decimator, improving bandwidth

37. - E7G05

How can unwanted ringing and audio instability be prevented in an op-amp RC audio filter circuit?

Select	Answer
A	Increase both gain and Q
B	Restrict gain but increase Q
C	Restrict both gain and Q
D	Restrict Q but increase gain

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 GPS signal reference
C	All these choices are correct
D	Use a rubidium stabilized reference oscillator

39. - E8A08

Why would a direct or flash conversion analog-to-digital converter be useful for a software defined radio?

Select	Answer
A	All these choices are correct
B	Very high speed allows digitizing high frequencies
C	Very low power consumption decreases frequency drift
D	Immunity to out-of-sequence coding reduces spurious responses

40. - E8B10

What is frequency division multiplexing?

Select	Answer
A	Two or more information streams are merged into a baseband, which then modulates the transmitter
B	Two or more information streams are merged into a digital combiner, which then pulse position modulates the transmitter
C	The transmitted signal is divided into packets of information
D	The transmitted signal jumps from band to band at a predetermined rate

41. - E8C11

What is the relationship between symbol rate and baud?

Select	Answer
A	They are the same
B	Baud is only used for RTTY
C	Symbol rate is only used for packet-based modes
D	Baud is twice the symbol rate

42. - E8D06

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

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

43. - E9A06

What is the effective radiated power relative to a dipole of a repeater station with 200 watts transmitter power output, 4 dB feed line loss, 3.2 dB duplexer loss, 0.8 dB circulator loss, and 10 dBd antenna gain?

Select	Answer
A	300 watts
B	2000 watts
C	317 watts
D	126 watts

44. - E9B05

What type of antenna pattern is shown in Figure E9-2?

Select	Answer
A	Azimuth
B	Radiation resistance
C	Polarization
D	Elevation

45. - E9C09

Which of the following describes a G5RV antenna?

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

46. - E9D06

What happens to the SWR bandwidth when one or more loading coils are used to resonate an electrically short antenna?

Select	Answer
A	It is unchanged if the loading coil is located at a voltage maximum point
B	It is decreased
C	It is unchanged if the loading coil is located at the feed point
D	It is increased

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. - E9F02

Which of the following has the biggest effect on the velocity factor of a transmission line?

Select	Answer
A	The center conductor resistivity
B	The termination impedance
C	The line length
D	Dielectric materials used in the line

49. - E9G11

How are the wavelength scales on a Smith chart calibrated?

Select	Answer
A	In fractions of transmission line electrical wavelength
B	In fractions of antenna electrical frequency
C	In fractions of transmission line electrical frequency
D	In fractions of antenna electrical wavelength

50. - E9H04

What is an advantage of placing a grounded electrostatic shield around a small loop direction-finding antenna?

Select	Answer
A	It increases signal strength by providing a better match to the feed line
B	It adds capacitive loading, increasing the bandwidth of the antenna
C	It eliminates unbalanced capacitive coupling to the surroundings, improving the nulls
D	It eliminates tracking errors caused by strong out-of-band signals

Figure E5-1

Figure E9-2