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

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1. - E1A03

With your transceiver displaying the carrier frequency of phone signals, you hear a station calling CQ on 14.349 MHz USB. Is it legal to return the call using upper sideband on the same frequency?

Select	Answer
A	No, U.S. stations are not permitted to use phone emissions above 14.340 MHz
B	Yes, because the displayed frequency is within the 20 meter band
C	Yes, because you were not the station calling CQ
D	No, the sideband will extend beyond the band edge

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

3. - E1C05

When may an automatically controlled station originate third party communications?

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

4. - E1D07

Which amateur service HF bands have frequencies authorized for space stations?

Select	Answer
A	Only the 40 m, 20 m, 17 m, 15 m, 12 m and 10 m bands
B	All HF bands
C	Only the 40 m, 30 m, 20 m, 15 m, 12 m and 10 m bands
D	Only the 40 m, 20 m, 17 m, 15 m and 10 m bands

5. - E1E05

What is the minimum passing score on amateur operator license examinations?

Select	Answer
A	Minimum passing score of 70%
B	Minimum passing score of 77%
C	Minimum passing score of 80%
D	Minimum passing score of 74%

6. - E1F01

On what frequencies are spread spectrum transmissions permitted?

Select	Answer
A	Only on amateur frequencies above 50 MHz
B	Only on amateur frequencies above 420 MHz
C	Only on amateur frequencies above 222 MHz
D	Only on amateur frequencies above 144 MHz

7. - E2A13

What type of satellite appears to stay in one position in the sky?

Select	Answer
A	HEO
B	Geostationary
C	Geomagnetic
D	LEO

8. - E2B13

How many lines are commonly used in each frame of an amateur slow-scan color television picture?

Select	Answer
A	180 or 360
B	30 or 60
C	60 or 100
D	128 or 256

9. - E2C08

Which of the following contacts may be confirmed through the U.S. QSL bureau system?

Select	Answer
A	Special event contacts between stations in the U.S.
B	Repeater contacts between U.S. club members
C	Contacts between a U.S. station and a non-U.S. station
D	Contacts using tactical call signs

10. - E2D06

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

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

11. - E2E06

What is the most common data rate used for HF packet?

Select	Answer
A	48 baud
B	110 baud
C	300 baud
D	1200 baud

12. - E3A10

Which type of atmospheric structure can create a path for microwave propagation?

Select	Answer
A	Dust devil
B	Wind shear
C	Temperature inversion
D	The jet stream

13. - E3B07

Which of the following could account for hearing an echo on the received signal of a distant station?

Select	Answer
A	Transmit frequency is higher than the MUF
B	High D layer absorption
C	Meteor scatter
D	Receipt of a signal by more than one path

14. - 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	Downward bending due to aurora refraction
D	E-region skip

15. - E4A13

How is the compensation of an oscilloscope probe typically adjusted?

Select	Answer
A	A DC voltage standard is displayed and the probe is adjusted until the displayed voltage is accurate
B	A frequency standard is displayed and the probe is adjusted until the deflection time is accurate
C	A square wave is displayed and the probe is adjusted until the horizontal portions of the displayed wave are as nearly flat as possible
D	A high frequency sine wave is displayed and the probe is adjusted for maximum amplitude

16. - E4B08

Which of the following is a characteristic of a good DC voltmeter?

Select	Answer
A	High reluctance input
B	Low reluctance input
C	Low impedance input
D	High impedance input

17. - E4C09

Which of the following choices is a good reason for selecting a high frequency for the design of the IF in a conventional HF or VHF communications receiver?

Select	Answer
A	Improved receiver noise figure
B	Easier for front-end circuitry to eliminate image responses
C	Reduced drift
D	Fewer components in the receiver

18. - E4D14

Which of the following is a way to reduce the likelihood of receiver desensitization?

Select	Answer
A	Increase the receiver front end gain
B	Decrease the RF bandwidth of the receiver
C	Switch from fast AGC to slow AGC
D	Raise the receiver IF frequency

19. - E4E06

What is a major cause of atmospheric static?

Select	Answer
A	Solar radio frequency emissions
B	Meteor showers
C	Thunderstorms
D	Geomagnetic storms

20. - E5A16

What is the resonant frequency of a parallel RLC circuit if R is 33 ohms, L is 50 microhenrys and C is 10 picofarads?

Select	Answer
A	7.12 MHz
B	23.5 MHz
C	7.12 kHz
D	23.5 kHz

21. - E5B02

What is the term for the time it takes for a charged capacitor in an RC circuit to discharge to 36.8% of its initial voltage?

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

22. - E5C03

Which of the following represents an inductive reactance in polar coordinates?

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

23. - E5D08

What type of energy is stored in an electromagnetic or electrostatic field?

Select	Answer
A	Potential energy
B	Thermodynamic energy
C	Kinetic energy
D	Electromechanical energy

24. - E6A10

In Figure E6-2, what is the schematic symbol for an N-channel dual-gate MOSFET?

Select	Answer
A	4
B	6
C	5
D	2

25. - E6B13

What type of bias is required for an LED to emit light?

Select	Answer
A	Inductive bias
B	Reverse bias
C	Forward bias
D	Zero bias

26. - E6C12

What is BiCMOS logic?

Select	Answer
A	A FET logic family based on bimetallic semiconductors
B	A logic device with two CMOS circuits per package
C	An integrated circuit logic family using both bipolar and CMOS transistors
D	A logic family based on bismuth CMOS devices

27. - E6D16

What is the common name for a capacitor connected across a transformer secondary that is used to absorb transient voltage spikes?

Select	Answer
A	Feedback capacitor
B	Trimmer capacitor
C	Clipper capacitor
D	Snubber capacitor

28. - E6E05

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

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

29. - E6F02

What happens to the conductivity of a photoconductive material when light shines on it?

Select	Answer
A	It stays the same
B	It increases
C	It becomes unstable
D	It decreases

30. - E7A09

What logical operation is performed by an exclusive NOR gate?

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

31. - E7B14

Why are switching amplifiers more efficient than linear amplifiers?

Select	Answer
A	Linear amplifiers have high gain resulting in higher harmonic content
B	Switching amplifiers use push-pull circuits
C	The power transistor is at saturation or cut off most of the time, resulting in low power dissipation
D	Switching amplifiers operate at higher voltages

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

33. - E7D15

What is the purpose of a "step-start" circuit in a high voltage power supply?

Select	Answer
A	To provide a dual-voltage output for reduced power applications
B	To allow the filter capacitors to charge gradually
C	To compensate for variations of the incoming line voltage
D	To allow for remote control of the power supply

34. - E7E01

Which of the following can be used to generate FM phone emissions?

Select	Answer
A	A balanced modulator on the audio amplifier
B	A reactance modulator on the oscillator
C	A balanced modulator on the oscillator
D	A reactance modulator on the final amplifier

35. - E7F12

What digital process is applied to I and Q signals in order to recover the baseband modulation information?

Select	Answer
A	Quadrature mixing
B	Signal conditioning
C	Fast Fourier Transform
D	Decimation

36. - E7G09

What will be the output voltage of the circuit shown in Figure E7-4 if R1 is 1000 ohms, RF is 10,000 ohms, and 0.23 volts DC is applied to the input?

Select	Answer
A	2.3 volts
B	-0.23 volts
C	0.23 volts
D	-2.3 volts

37. - E7H11

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

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

38. - E8A05

What would be the most accurate way of measuring the RMS voltage of a complex waveform?

Select	Answer
A	By using a grid dip meter
B	By using an absorption wave meter
C	By measuring the voltage with a D'Arsonval meter
D	By measuring the heating effect in a known resistor

39. - E8B06

What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus or minus 7.5 kHz when the maximum modulation frequency is 3.5 kHz?

Select	Answer
A	0.214
B	2.14
C	47
D	0.47

40. - E8C01

How is Forward Error Correction implemented?

Select	Answer
A	By transmitting extra data that may be used to detect and correct transmission errors
B	By the receiving station repeating each block of three data characters
C	By transmitting a special algorithm to the receiving station along with the data characters
D	By varying the frequency shift of the transmitted signal according to a predefined algorithm

41. - E8D03

How does the spread spectrum technique of frequency hopping work?

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

42. - E9A03

Why would one need to know the feed point impedance of an antenna?

Select	Answer
A	To calculate the front-to-back ratio of the antenna
B	To calculate the front-to-side ratio of the antenna
C	To match impedances in order to minimize standing wave ratio on the transmission line
D	To measure the near-field radiation density from a transmitting antenna

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

44. - E9C05

What is an OCFD antenna?

Select	Answer
A	An eight band dipole antenna using octophase filters
B	A remotely tunable dipole antenna using orthogonally controlled frequency diversity
C	A multiband dipole antenna using one-way circular polarization for frequency diversity
D	A dipole feed approximately 1/3 the way from one end with a 4:1 balun to provide multiband operation

45. - E9D10

What happens to feed point impedance at the base of a fixed length HF mobile antenna as the frequency of operation is lowered?

Select	Answer
A	The radiation resistance increases and the capacitive reactance increases
B	The radiation resistance decreases and the capacitive reactance decreases
C	The radiation resistance decreases and the capacitive reactance increases
D	The radiation resistance increases and the capacitive reactance decreases

46. - E9E05

How must the driven element in a 3-element Yagi be tuned to use a hairpin matching system?

Select	Answer
A	The driven element reactance must be inductive
B	The driven element reactance must be capacitive
C	The driven element resonance must be lower than the operating frequency
D	The driven element radiation resistance must be higher than the characteristic impedance of the transmission line

47. - E9F03

Why is the physical length of a coaxial cable transmission line shorter than its electrical length?

Select	Answer
A	Skin effect is less pronounced in the coaxial cable
B	The characteristic impedance is higher in a parallel feed line
C	Electrical signals move more slowly in a coaxial cable than in air
D	The surge impedance is higher in a parallel feed line

48. - E9G01

Which of the following can be calculated using a Smith chart?

Select	Answer
A	Impedance along transmission lines
B	Radio propagation
C	Radiation resistance
D	Antenna radiation pattern

49. - E9H08

What is the function of a sense antenna?

Select	Answer
A	It provides diversity reception that cancels multipath signals
B	It modifies the pattern of a DF antenna array to provide a null in one direction
C	It increases the sensitivity of a DF antenna array
D	It allows DF antennas to receive signals at different vertical angles

50. - E0A09

Which insulating material commonly used as a thermal conductor for some types of electronic devices is extremely toxic if broken or crushed and the particles are accidentally inhaled?

Select	Answer
A	Mica
B	Zinc oxide
C	Uranium Hexafluoride
D	Beryllium Oxide

Figure E6-2

Figure E7-4