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

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

2. - E1B05

What is the National Radio Quiet Zone?

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

3. - E1C03

How do the control operator responsibilities of a station under automatic control differ from one under local control?

Select	Answer
A	Under local control there is no control operator
B	Under automatic control the control operator is not required to be present at the control point
C	Under local control a control operator is not required to be present at a control point
D	Under automatic control there is no control operator

4. - E1D04

What is an Earth station in the amateur satellite service?

Select	Answer
A	An amateur station within 50 km of the Earth's surface intended for communications with amateur stations by means of objects in space
B	Any amateur station on the surface of the Earth
C	An amateur station that transmits telemetry consisting of measurement of upper atmosphere
D	An amateur station that is not able to communicate using amateur satellites

5. - E1E14

For which types of out-of-pocket expenses do the Part 97 rules state that VEs and VECs may be reimbursed?

Select	Answer
A	Providing amateur operator license examination preparation training materials
B	Teaching an amateur operator license examination preparation course
C	No expenses are authorized for reimbursement
D	Preparing, processing, administering and coordinating an examination for an amateur radio license

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

7. - E2A01

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

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

8. - E2B02

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

Select	Answer
A	30
B	1080
C	60
D	525

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

10. - E2D06

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

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

11. - E2E08

Which of the following HF digital modes can be used to transfer binary files?

Select	Answer
A	Hellschreiber
B	AMTOR
C	RTTY
D	PACTOR

12. - E3A14

From the contiguous 48 states, in which approximate direction should an antenna be pointed to take maximum advantage of aurora propagation?

Select	Answer
A	East
B	West
C	North
D	South

13. - E3B10

What is the cause of gray-line propagation?

Select	Answer
A	At mid-afternoon, the Sun heats the ionosphere decreasing radio wave refraction and the MUF
B	At midday, the Sun super heats the ionosphere causing increased refraction of radio waves
C	In darkness, solar absorption drops greatly while atmospheric ionization remains steady
D	At twilight and sunrise, D-layer absorption is low while E-layer and F-layer propagation remains high

14. - E3C10

What does the 304A solar parameter measure?

Select	Answer
A	UV emissions at 304 angstroms, correlated to solar flux index
B	The solar wind velocity at 304 degrees from the solar equator, correlated to solar activity
C	The solar emission at 304 GHz, correlated to X-Ray flare levels
D	The ratio of X-Ray flux to radio flux, correlated to sunspot number

15. - E4A15

What is an advantage of a period-measuring frequency counter over a direct-count type?

Select	Answer
A	It provides improved resolution of low-frequency signals within a comparable time period
B	It can directly measure the modulation index of an FM transmitter
C	It can run on battery power for remote measurements
D	It does not require an expensive high-precision time base

16. - E4B11

How should an antenna analyzer be connected when measuring antenna resonance and feed point impedance?

Select	Answer
A	Connect the analyzer via a high-impedance transformer to the antenna
B	Loosely couple the analyzer near the antenna base
C	Connect the antenna feed line directly to the analyzer's connector
D	Loosely couple the antenna and a dummy load to the analyzer

17. - E4C15

What is usually the primary source of noise that is heard from an HF receiver with an antenna connected?

Select	Answer
A	Atmospheric noise
B	Induction motor noise
C	Detector noise
D	Receiver front-end noise

18. - E4D02

Which of the following describes two problems caused by poor dynamic range in a communications receiver?

Select	Answer
A	Oscillator instability requiring frequent retuning and loss of ability to recover the opposite sideband
B	Oscillator instability and severe audio distortion of all but the strongest received signals
C	Cross-modulation of the desired signal and insufficient audio power to operate the speaker
D	Cross-modulation of the desired signal and desensitization from strong adjacent signals

19. - E4E09

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

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

20. - E5A15

Which of the following can increase Q for inductors and capacitors?

Select	Answer
A	Lower self-resonant frequency
B	Lower reactance
C	Lower losses
D	Higher self-resonant frequency

21. - E5B05

What happens to the magnitude of a reactance when it is converted to a susceptance?

Select	Answer
A	It is unchanged
B	It is shifted by 90 degrees
C	The sign is reversed
D	The magnitude of the susceptance is the reciprocal of the magnitude of the reactance

22. - E5C04

Which of the following represents a capacitive reactance in polar coordinates?

Select	Answer
A	A negative phase angle
B	A positive phase angle
C	A positive real part
D	A negative real part

23. - E5D12

How many watts are consumed in a circuit having a power factor of 0.2 if the input is 100-VAC at 4 amperes?

Select	Answer
A	50 watts
B	2000 watts
C	80 watts
D	400 watts

24. - E6A08

What term indicates the frequency at which the grounded-base current gain of a transistor has decreased to 0.7 of the gain obtainable at 1 kHz?

Select	Answer
A	Beta cutoff frequency
B	Alpha rejection frequency
C	Alpha cutoff frequency
D	Corner frequency

25. - E6B10

In Figure E6-3, what is the schematic symbol for a light-emitting diode?

Select	Answer
A	1
B	7
C	6
D	5

26. - E6C09

What is a Programmable Logic Device (PLD)?

Select	Answer
A	A programmable collection of logic gates and circuits in a single integrated circuit
B	Programmable equipment used for testing digital logic integrated circuits
C	A device to control industrial equipment
D	An algorithm for simulating logic functions during circuit design

27. - E6D04

Which materials are commonly used as a slug core in a variable inductor?

Select	Answer
A	Ferrite and brass
B	Polystyrene and polyethylene
C	Cobalt and aluminum
D	Teflon and Delrin

28. - E6E05

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

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

29. - E6F04

What is the photovoltaic effect?

Select	Answer
A	The tendency of a battery to discharge when used outside
B	The conversion of light to electrical energy
C	The conversion of voltage to current when exposed to light
D	The conversion of electrical energy to mechanical energy

30. - E7A09

What logical operation is performed by an exclusive NOR gate?

Select	Answer
A	It produces logic "1" at its output only if all inputs are logic "1"
B	It produces logic "1" at its output if any single input is logic "1"
C	It produces logic "0" at its output if any single input is logic "1"
D	It produces logic "0" at its output only if all inputs are logic "0"

31. - E7B16

What is the effect of intermodulation products in a linear power amplifier?

Select	Answer
A	Low efficiency
B	Creation of parasitic oscillations
C	All of these choices are correct
D	Transmission of spurious signals

32. - E7C04

How does an impedance-matching circuit transform a complex impedance to a resistive impedance?

Select	Answer
A	It cancels the reactive part of the impedance and changes the resistive part to a desired value
B	Network resistances are substituted for load resistances and reactances are matched to the resistances
C	It introduces transconductance to cancel the reactive part of impedance
D	It introduces negative resistance to cancel the resistive part of impedance

33. - E7D06

What is the purpose of Q1 in the circuit shown in Figure E7-3?

Select	Answer
A	It provides a constant load for the voltage source
B	It provides negative feedback to improve regulation
C	It provides D1 with current
D	It increases the current-handling capability of the regulator

34. - E7E03

How does an analog phase modulator function?

Select	Answer
A	By varying the tuning of a microphone preamplifier to produce AM signals
B	By varying the tuning of an amplifier tank circuit to produce PM signals
C	By varying the tuning of a microphone preamplifier to produce PM signals
D	By varying the tuning of an amplifier tank circuit to produce AM signals

35. - E7F11

What sets the minimum detectable signal level for an SDR in the absence of atmospheric or thermal noise?

Select	Answer
A	Reference voltage level and sample width in bits
B	Missing codes and jitter
C	Data storage transfer rate
D	Sample clock phase noise

36. - E7G01

What is the typical output impedance of an integrated circuit op-amp?

Select	Answer
A	Very low
B	100 ohms
C	Very high
D	1000 ohms

37. - E7H14

What is a phase-locked loop circuit?

Select	Answer
A	An electronic servo loop consisting of a ratio detector, reactance modulator, and voltage-controlled oscillator
B	An electronic circuit consisting of a precision push-pull amplifier with a differential input
C	An electronic circuit also known as a monostable multivibrator
D	An electronic servo loop consisting of a phase detector, a low-pass filter, a voltage-controlled oscillator, and a stable reference oscillator

38. - E8A02

What type of wave has a rise time significantly faster than its fall time (or vice versa)?

Select	Answer
A	A sine wave
B	A cosine wave
C	A sawtooth wave
D	A square wave

39. - E8B10

What describes frequency division multiplexing?

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

40. - E8C04

What technique is used to minimize the bandwidth requirements of a PSK31 signal?

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

41. - E8D03

How does the spread spectrum technique of frequency hopping work?

Select	Answer
A	The frequency of the transmitted signal is changed very rapidly according to a particular sequence also used by the receiving station
B	If interference is detected by the receiver it will signal the transmitter to change frequencies
C	If interference is detected by the receiver it will signal the transmitter to wait until the frequency is clear
D	A pseudo-random binary bit stream is used to shift the phase of an RF carrier very rapidly in a particular sequence

42. - E9A10

Which of the following choices is a way to improve the efficiency of a ground-mounted quarter-wave vertical antenna?

Select	Answer
A	Reduce the diameter of the radiating element
B	Shorten the radiating element
C	Install a good radial system
D	Isolate the coax shield from ground

43. - E9B04

What may occur when a directional antenna is operated at different frequencies within the band for which it was designed?

Select	Answer
A	The E-field and H-field patterns may reverse
B	The gain may change depending on frequency
C	Element spacing limits could be exceeded
D	Feed point impedance may become negative

44. - E9C03

What is the radiation pattern of two 1/4 wavelength vertical antennas spaced a 1/2 wavelength apart and fed in phase?

Select	Answer
A	A Figure-8 end-fire along the axis of the array
B	Omni-directional
C	A Figure-8 broadside to the axis of the array
D	Cardioid

45. - E9D08

What happens as the Q of an antenna increases?

Select	Answer
A	SWR bandwidth increases
B	Gain is reduced
C	SWR bandwidth decreases
D	More common-mode current is present on the feed line

46. - E9E06

What is the equivalent lumped-constant network for a hairpin matching system of a 3-element Yagi?

Select	Answer
A	A shunt inductor
B	A series capacitor
C	Pi-network
D	Pi-L-network

47. - E9F11

What impedance does a 1/8 wavelength transmission line present to a generator when the line is open at the far end?

Select	Answer
A	The same as the input impedance of the final generator stage
B	The same as the characteristic impedance of the line
C	A capacitive reactance
D	An inductive reactance

48. - E9G10

What do the arcs on a Smith chart represent?

Select	Answer
A	Points with constant resistance
B	Frequency
C	Points with constant reactance
D	SWR

49. - E9H05

What is the main drawback of a wire-loop antenna for direction finding?

Select	Answer
A	It receives equally well in all directions
B	It is practical for use only on VHF bands
C	It is non-rotatable
D	It has a bidirectional pattern

50. - E0A07

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

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

Figure E6-3

Figure E7-3