US Amateur Radio - Amateur Extra (Element 4, 2016-2020) Practice Test

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1. - E1A06

Where must the carrier frequency of a CW signal be set to comply with FCC rules for 60 meter operation?

Select	Answer
A	At the highest frequency of the channel
B	At the center frequency of the channel
C	On any frequency where the signal's sidebands are within the channel
D	At the lowest frequency of the channel

2. - E1B06

Which of the following additional rules apply if you are installing an amateur station antenna at a site at or near a public use airport?

Select	Answer
A	You may have to notify the Federal Aviation Administration and register it with the FCC as required by Part 17 of FCC rules
B	No special rules apply if your antenna structure will be less than 300 feet in height
C	You must obtain a construction permit from the airport zoning authority
D	You must file an Environmental Impact Statement with the EPA before construction begins

3. - E1C10

What types of amateur stations may automatically retransmit the radio signals of other amateur stations?

Select	Answer
A	Only auxiliary, repeater or space stations
B	Only auxiliary, beacon or space stations
C	Only beacon, repeater or space stations
D	Only earth stations, repeater stations or model craft

4. - E1D08

Which VHF amateur service bands have frequencies available for space stations?

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

5. - E1E02

Where are the questions for all written U.S. amateur license examinations listed?

Select	Answer
A	In FCC Part 97
B	In the appropriate FCC Report and Order
C	In a question pool maintained by the FCC
D	In a question pool maintained by all the VECs

6. - E1F09

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

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

7. - E2A02

What is the direction of a descending pass for an amateur satellite?

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

8. - E2B17

What is the approximate bandwidth of a slow-scan TV signal?

Select	Answer
A	6 MHz
B	3 kHz
C	600 Hz
D	2 MHz

9. - E2C12

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

10. - E2D07

What digital protocol is used by APRS?

Select	Answer
A	802.11
B	PACTOR
C	AMTOR
D	AX.25

11. - E2E12

Which type of control is used by stations using the Automatic Link Enable (ALE) protocol?

Select	Answer
A	ALE can use any type of control
B	Automatic
C	Local
D	Remote

12. - E3A07

Atmospheric ducts capable of propagating microwave signals often form over what geographic feature?

Select	Answer
A	Urban areas
B	Mountain ranges
C	Forests
D	Bodies of water

13. - E3B05

Which amateur bands typically support long-path propagation?

Select	Answer
A	160 meters to 40 meters
B	6 meters to 2 meters
C	160 meters to 10 meters
D	30 meters to 10 meters

14. - E3C13

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

Select	Answer
A	Vertical
B	Horizontal
C	Circular
D	Elliptical

15. - E4A01

Which of the following parameter determines the bandwidth of a digital or computer-based oscilloscope?

Select	Answer
A	Sample resolution
B	Input impedance
C	Sampling rate
D	Input capacitance

16. - E4B05

If a frequency counter with a specified accuracy of +/- 10 ppm reads 146,520,000 Hz, what is the most the actual frequency being measured could differ from the reading?

Select	Answer
A	146.52 Hz
B	146.52 kHz
C	1465.20 Hz
D	10 Hz

17. - E4C05

What does a value of -174 dBm/Hz represent with regard to the noise floor of a receiver?

Select	Answer
A	The minimum detectable signal as a function of receive frequency
B	The galactic noise contribution to minimum detectable signal
C	The theoretical noise at the input of a perfect receiver at room temperature
D	The noise figure of a 1 Hz bandwidth receiver

18. - E4D06

What is the term for unwanted signals generated by the mixing of two or more signals?

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

19. - E4E09

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

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

20. - E5A01

What can cause the voltage across reactances in series to be larger than the voltage applied to them?

Select	Answer
A	Resonance
B	Conductance
C	Resistance
D	Capacitance

21. - 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?

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

22. - E5C02

How are impedances described in polar coordinates?

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

23. - E5D18

How many watts are consumed in a circuit having a power factor of 0.71 if the apparent power is 500VA?

Select	Answer
A	252 W
B	1.42 mW
C	704 W
D	355 W

24. - E6A06

What is the beta of a bipolar junction transistor?

Select	Answer
A	The switching speed of the transistor
B	The change in collector current with respect to base current
C	The frequency at which the current gain is reduced to 1
D	The breakdown voltage of the base to collector junction

25. - E6B04

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

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

26. - E6C03

What is tri-state logic?

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

27. - E6D10

What is a primary advantage of using a toroidal core instead of a solenoidal core in an inductor?

Select	Answer
A	Toroidal cores confine most of the magnetic field within the core material
B	Toroidal cores make it easier to couple the magnetic energy into other components
C	Toroidal cores have lower Q characteristics
D	Toroidal cores exhibit greater hysteresis

28. - E6E02

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

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

29. - E6F08

Why are optoisolators often used in conjunction with solid state circuits when switching 120VAC?

Select	Answer
A	Optoisolators provide a very high degree of electrical isolation between a control circuit and the circuit being switched
B	Optoisolators eliminate the effects of reflected light in the control circuit
C	Optoisolators provide a low impedance link between a control circuit and a power circuit
D	Optoisolators provide impedance matching between the control circuit and power circuit

30. - E7A05

Which of the following is a circuit that continuously alternates between two states without an external clock?

Select	Answer
A	Astable multivibrator
B	J-K flip-flop
C	T flip-flop
D	Monostable multivibrator

31. - E7B04

Where on the load line of a Class A common emitter amplifier would bias normally be set?

Select	Answer
A	Where the load line intersects the voltage axis
B	At a point where the load line intersects the zero bias current curve
C	Approximately half-way between saturation and cutoff
D	At a point where the bias resistor equals the load resistor

32. - E7C13

What is one advantage of a Pi-matching network over an L-matching network consisting of a single inductor and a single capacitor?

Select	Answer
A	The Q of Pi-networks can be varied depending on the component values chosen
B	L-networks cannot perform impedance transformation
C	Pi-networks are designed for balanced input and output
D	Pi-networks have fewer components

33. - E7D02

What is one characteristic of a switching electronic voltage regulator?

Select	Answer
A	It is generally less efficient than a linear regulator
B	The resistance of a control element is varied in direct proportion to the line voltage or load current
C	The controlled device's duty cycle is changed to produce a constant average output voltage
D	It gives a ramp voltage at its output

34. - E7E05

What circuit is added to an FM transmitter to boost the higher audio frequencies?

Select	Answer
A	An audio prescaler
B	A pre-emphasis network
C	A de-emphasis network
D	A heterodyne suppressor

35. - E7F13

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

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

36. - E7G10

What absolute voltage gain can be expected from the circuit in Figure E7-4 when R1 is 1800 ohms and RF is 68 kilohms?

Select	Answer
A	0.03
B	38
C	1
D	76

37. - E7H03

How is positive feedback supplied in a Hartley oscillator?

Select	Answer
A	Through a capacitive divider
B	Through a neutralizing capacitor
C	Through a tapped coil
D	Through link coupling

38. - E8A08

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

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

39. - E8B07

Orthogonal Frequency Division Multiplexing is a technique used for which type of amateur communication?

Select	Answer
A	Extremely low-power contacts
B	EME
C	High speed digital modes
D	OFDM signals are not allowed on amateur bands

40. - E8C03

When performing phase shift keying, why is it advantageous to shift phase precisely at the zero crossing of the RF carrier?

Select	Answer
A	It improves carrier suppression
B	It is easier to demodulate with a conventional, non-synchronous detector
C	This results in the least possible transmitted bandwidth for the particular mode
D	All of these choices are correct

41. - E8D01

Why are received spread spectrum signals resistant to interference?

Select	Answer
A	The high power used by a spread spectrum transmitter keeps its signal from being easily overpowered
B	The receiver is always equipped with a digital blanker
C	Signals not using the spread spectrum algorithm are suppressed in the receiver
D	If interference is detected by the receiver it will signal the transmitter to change frequencies

42. - E9A14

What is meant by the radiation resistance of an antenna?

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

43. - E9B16

How many elevation lobes appear in the forward direction of the antenna radiation pattern shown in Figure E9-2?

Select	Answer
A	7
B	3
C	4
D	1

44. - E9C06

What is the effect of a terminating resistor on a rhombic antenna?

Select	Answer
A	It reflects the standing waves on the antenna elements back to the transmitter
B	It changes the radiation pattern from horizontal to vertical polarization
C	It changes the radiation pattern from bidirectional to unidirectional
D	It decreases the ground loss

45. - E9D13

What usually occurs if a Yagi antenna is designed solely for maximum forward gain?

Select	Answer
A	The frequency response is widened over the whole frequency band
B	The SWR is reduced
C	The front-to-back ratio decreases
D	The front-to-back ratio increases

46. - E9E08

Which of the following measurements is characteristic of a mismatched transmission line?

Select	Answer
A	A reflection coefficient greater than 1
B	An SWR less than 1:1
C	A dielectric constant greater than 1
D	An SWR greater than 1:1

47. - E9F16

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

48. - E9G08

What is the process of normalization with regard to a Smith chart?

Select	Answer
A	Reassigning prime center with regard to the reactance axis
B	Reassigning reactance values with regard to the resistance axis
C	Reassigning impedance values with regard to the prime center
D	Reassigning resistance values with regard to the reactance axis

49. - E9H04

What is an advantage of using a shielded loop antenna for direction finding?

Select	Answer
A	It is electro statically balanced against ground, giving better nulls
B	It eliminates tracking errors caused by strong out-of-band signals
C	It automatically cancels ignition noise in mobile installations
D	It allows stations to communicate without giving away their position

50. - E0A08

What does SAR measure?

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

Figure E7-4

Figure E9-2