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

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1. - E0A06

Why are there separate electric (E) and magnetic (H) field MPE limits?

Select	Answer
A	Ground reflections and scattering make the field strength vary with location
B	All these choices are correct
C	The body reacts to electromagnetic radiation from both the E and H fields
D	E field and H field radiation intensity peaks can occur at different locations

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	14.149 MHz
B	14.100 MHz
C	14.349 MHz
D	14.070 MHz

3. - E1B10

What frequencies are authorized to an amateur station operating under RACES rules?

Select	Answer
A	Military Auxiliary Radio System (MARS) channels
B	Specific segments in the amateur service MF, HF, VHF and UHF bands
C	All amateur service frequencies authorized to the control operator
D	Specific local government channels

4. - E1C12

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

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

5. - E1D03

What is a space telecommand station?

Select	Answer
A	An amateur station located on the surface of the Earth for communication with other Earth stations by means of Earth satellites
B	An amateur station located in a satellite or a balloon more than 50 kilometers above the surface of the Earth
C	An amateur station that transmits communications to initiate, modify or terminate functions of a space station
D	An amateur station that receives telemetry from a satellite or balloon more than 50 kilometers above the surface of the Earth

6. - E1E02

Who does Part 97 task with maintaining the pools of questions for all U.S. amateur license examinations?

Select	Answer
A	The ARRL
B	The VECs
C	The VEs
D	The FCC

7. - E1F10

Who may be the control operator of an auxiliary station?

Select	Answer
A	Only Amateur Extra Class operators
B	Any licensed amateur operator
C	Only Technician, General, Advanced or Amateur Extra Class operators
D	Only General, Advanced or Amateur Extra Class operators

8. - E2A13

Which of the following techniques is normally used by low Earth orbiting digital satellites to relay messages around the world?

Select	Answer
A	Store-and-forward
B	Digipeating
C	Node hopping
D	Multi-satellite relaying

9. - E2B03

How is an interlaced scanning pattern generated in a fast-scan (NTSC) television system?

Select	Answer
A	By scanning each field from bottom to top
B	By scanning lines from left to right in one field and right to left in the next
C	By scanning two fields simultaneously
D	By scanning odd numbered lines in one field and even numbered lines in the next

10. - E2C10

Why might a DX station state that they are listening on another frequency?

Select	Answer
A	To improve operating efficiency by reducing interference
B	All these choices are correct
C	Because the DX station may be transmitting on a frequency that is prohibited to some responding stations
D	To separate the calling stations from the DX station

11. - E2D01

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

Select	Answer
A	WSPR
B	MSK144
C	APRS
D	Hellschreiber

12. - E2E09

Which of the following HF digital modes uses variable-length coding for bandwidth efficiency?

Select	Answer
A	MT63
B	PSK31
C	RTTY
D	PACTOR

13. - E3A03

When scheduling EME contacts, which of these conditions will generally result in the least path loss?

Select	Answer
A	When the moon is at apogee
B	When the moon is at perigee
C	When the MUF is above 30 MHz
D	When the moon is full

14. - E3B02

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

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

15. - E3C13

What type of polarization is best for ground-wave propagation?

Select	Answer
A	Circular
B	Horizontal
C	Elliptical
D	Vertical

16. - E4A02

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

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

17. - E4B01

Which of the following factors most affects the accuracy of a frequency counter?

Select	Answer
A	Time base accuracy
B	Temperature coefficient of the logic
C	Input attenuator accuracy
D	Decade divider accuracy

18. - E4C03

What is the term for the suppression in an FM receiver of one signal by another stronger signal on the same frequency?

Select	Answer
A	Frequency discrimination
B	Desensitization
C	Capture effect
D	Cross-modulation interference

19. - E4D10

What does a third-order intercept level of 40 dBm mean with respect to receiver performance?

Select	Answer
A	The receiver can tolerate signals up to 40 dB above the noise floor without producing third-order intermodulation products
B	A pair of 1 mW input signals will produce a third-order intermodulation product that is 40 dB stronger than the input signal
C	Signals less than 40 dBm will not generate audible third-order intermodulation products
D	A pair of 40 dBm input signals will theoretically generate a third-order intermodulation product that has the same output amplitude as either of the input signals

20. - E4E03

Which of the following signals might a receiver noise blanker be able to remove from desired signals?

Select	Answer
A	Signals that appear across a wide bandwidth
B	Signals that have a sharply peaked frequency distribution
C	Signals that are constant at all IF levels
D	Signals that appear at one IF but not another

21. - E5A07

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

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

22. - E5B01

What is the term for the time required for the capacitor in an RC circuit to be charged to 63.2% of the applied voltage or to discharge to 36.8% of its initial voltage?

Select	Answer
A	One time constant
B	One exponential period
C	An exponential rate of one
D	A time factor of one

23. - E5C02

How are impedances described in polar coordinates?

Select	Answer
A	By real and imaginary parts
B	By phase angle and magnitude
C	By X and R values
D	By Y and G values

24. - E5D03

What is microstrip?

Select	Answer
A	Short lengths of coax mounted on printed circuit boards to minimize time delay between microwave circuits
B	Precision printed circuit conductors above a ground plane that provide constant impedance interconnects at microwave frequencies
C	Lightweight transmission line made of common zip cord
D	Miniature coax used for low power applications

25. - E6A12

Why do many MOSFET devices have internally connected Zener diodes on the gates?

Select	Answer
A	To keep the gate voltage within specifications and prevent the device from overheating
B	To provide a voltage reference for the correct amount of reverse-bias gate voltage
C	To reduce the chance of static damage to the gate
D	To protect the substrate from excessive voltages

26. - E6B02

What is an important characteristic of a Schottky diode as compared to an ordinary silicon diode when used as a power supply rectifier?

Select	Answer
A	Less forward voltage drop
B	More constant reverse avalanche voltage
C	Much higher reverse voltage breakdown
D	Longer carrier retention time

27. - E6C06

Why do CMOS digital integrated circuits have high immunity to noise on the input signal or power supply?

Select	Answer
A	The input switching threshold is about two times the power supply voltage
B	Large bypass capacitance is inherent
C	The input switching threshold is about one-half the power supply voltage
D	Bandwidth is very limited

28. - E6D11

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

Select	Answer
A	Powdered iron
B	Ferrite
C	Brass
D	Ceramic

29. - E6E02

Which of the following device packages is a through-hole type?

Select	Answer
A	Ball grid array
B	SOT
C	DIP
D	PLCC

30. - E6F10

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

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

31. - E7A03

Which of the following can divide the frequency of a pulse train by 2?

Select	Answer
A	An OR gate
B	An XOR gate
C	A flip-flop
D	A multiplexer

32. - E7B12

What type of amplifier circuit is shown in Figure E7-1?

Select	Answer
A	Common collector
B	Common base
C	Common emitter
D	Emitter follower

33. - E7C08

Which of the following factors has the greatest effect on the bandwidth and response shape of a crystal ladder filter?

Select	Answer
A	The relative frequencies of the individual crystals
B	The DC voltage applied to the quartz crystal
C	The amplitude of the signals passing through the filter
D	The gain of the RF stage preceding the filter

34. - E7D08

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

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

35. - E7E04

What is one way a single-sideband phone signal can be generated?

Select	Answer
A	By driving a product detector with a DSB signal
B	By using a balanced modulator followed by a filter
C	By using a reactance modulator followed by a mixer
D	By using a loop modulator followed by a mixer

36. - E7F13

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

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

37. - E7G04

What is meant by the "op-amp input offset voltage"?

Select	Answer
A	The output voltage of the op-amp minus its input voltage
B	The potential between the amplifier input terminals of the op-amp in an open loop condition
C	The difference between the output voltage of the op-amp and the input voltage required in the immediately following stage
D	The differential input voltage needed to bring the open loop output voltage to zero

38. - E7H12

Which of the following must be done to ensure that a crystal oscillator provides the frequency specified by the crystal manufacturer?

Select	Answer
A	Provide the crystal with a specified parallel inductance
B	Bias the crystal at a specified current
C	Bias the crystal at a specified voltage
D	Provide the crystal with a specified parallel capacitance

39. - E8A11

Which of the following is a measure of the quality of an analog-to-digital converter?

Select	Answer
A	Reciprocal mixing
B	Power factor
C	Peak envelope power
D	Total harmonic distortion

40. - E8B01

What is the modulation index of an FM signal?

Select	Answer
A	The type of modulation used by the transmitter
B	The bandwidth of the transmitted signal divided by the modulating signal frequency
C	The ratio of frequency deviation to modulating signal frequency
D	The ratio of modulating signal amplitude to frequency deviation

41. - E8C04

What technique minimizes the bandwidth of a PSK31 signal?

Select	Answer
A	Use of trapezoidal data pulses
B	Reed-Solomon character encoding
C	Use of sinusoidal data pulses
D	Zero-sum character encoding

42. - E8D06

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

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

43. - E9A13

What term describes station output, taking into account all gains and losses?

Select	Answer
A	Half-power bandwidth
B	Apparent power
C	Power factor
D	Effective radiated power

44. - E9B06

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

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

45. - E9C12

Which of the following describes an Extended Double Zepp antenna?

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

46. - E9D12

Which of the following would provide the best RF ground for your station?

Select	Answer
A	A 50-ohm resistor connected to ground
B	An electrically short connection to 3 or 4 interconnected ground rods driven into the Earth
C	An electrically short connection to 3 or 4 interconnected ground rods via a series RF choke
D	An electrically short connection to a metal water pipe

47. - E9E06

Which of these feed line impedances would be suitable for constructing a quarter-wave Q-section for matching a 100-ohm loop to 50-ohm feed line?

Select	Answer
A	62 ohms
B	50 ohms
C	450 ohms
D	75 ohms

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	All these choices are correct
C	Foam dielectric has lower safe operating voltage limits
D	Foam dielectric has lower loss per unit of length

49. - E9G04

What are the two families of circles and arcs that make up a Smith chart?

Select	Answer
A	Voltage and impedance
B	Resistance and voltage
C	Reactance and voltage
D	Resistance and 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	High radiation angle
D	A very sharp peak

Figure E7-1

Figure E7-2

Figure E9-2