Amateur Extra Class Practice Test

Select the most correct answer for each question, then submit your practice test to check your score. This practice test randomly pulls one question from each topic in the Amateur Extra pool.

Good Luck!


Which of the following injuries can result from using high-power UHF or microwave transmitters?

Hearing loss caused by high voltage corona discharge
Blood clotting from the intense magnetic field
Localized heating of the body from RF exposure in excess of the MPE limits
Ingestion of ozone gas from the cooling system


What type of coordinate system is used in a Smith chart?

Voltage circles and current arcs
Resistance circles and reactance arcs
Voltage lines and current chords
Resistance lines and reactance chords


What is the primary reason that a high-frequency switching type high voltage power supply can be both less expensive and lighter in weight than a conventional power supply?

The inverter design does not require any output filtering
It uses a diode bridge rectifier for increased output
The high frequency inverter design uses much smaller transformers and filter components for an equivalent power output
It uses a large power factor compensation capacitor to create free power from the unused portion of the AC cycle


Which of the following oscillator circuits are commonly used in VFOs?

Pierce and Zener
Colpitts and Hartley
Armstrong and deForest
Negative feedback and balanced feedback


What is the approximate ratio of PEP-to-average power in a typical single-sideband phone signal?

2.5 to 1
25 to 1
1 to 1
100 to 1


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

Sample clock phase noise
Reference voltage level and sample width in bits
Data storage transfer rate
Missing codes and jitter


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

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


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

Larger bypass capacitors are used in CMOS circuit design
The input switching threshold is about two times the power supply voltage
The input switching threshold is about one-half the power supply voltage
Input signals are stronger


Which of the following is a common use of a hot-carrier diode?

As balanced mixers in FM generation
As a variable capacitance in an automatic frequency control circuit
As a constant voltage reference in a power supply
As a VHF/UHF mixer or detector


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

It increases
It decreases
It stays the same
It becomes unstable


Why are high-power RF amplifier ICs and transistors sometimes mounted in ceramic packages?

High-voltage insulating ability
Better dissipation of heat
Enhanced sensitivity to light
To provide a low-pass frequency response


What happens if a dip meter is too tightly coupled to a tuned circuit being checked?

Harmonics are generated
A less accurate reading results
Cross modulation occurs
Intermodulation distortion occurs


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

Polystyrene and polyethylene
Ferrite and brass
Teflon and Delrin
Cobalt and aluminum


When constructing a Beverage antenna, which of the following factors should be included in the design to achieve good performance at the desired frequency?

Its overall length must not exceed 1/4 wavelength
It must be mounted more than 1 wavelength above ground
It should be configured as a four-sided loop
It should be one or more wavelengths long


Which amateur band requires transmission on specific channels rather than on a range of frequencies?

12 meter band
17 meter band
30 meter band
60 meter band


How does ARQ accomplish error correction?

Special binary codes provide automatic correction
Special polynomial codes provide automatic correction
If errors are detected, redundant data is substituted
If errors are detected, a retransmission is requested


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

Monostable multivibrator
J-K flip-flop
T flip-flop
Astable multivibrator


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

Reactance of either the inductance or capacitance divided by the resistance
Reactance of either the inductance or capacitance multiplied by the resistance
Resistance divided by the reactance of either the inductance or capacitance
Reactance of the inductance multiplied by the reactance of the capacitance


What is the maximum permitted transmitter peak envelope power for an amateur station transmitting spread spectrum communications?

1 W
1.5 W
10 W
1.5 kW


How does JT65 improve EME communications?

It can decode signals many dB below the noise floor using FEC
It controls the receiver to track Doppler shift
It supplies signals to guide the antenna to track the Moon
All of these choices are correct


What is meant by automatic control of a station?

The use of devices and procedures for control so that the control operator does not have to be present at a control point
A station operating with its output power controlled automatically
Remotely controlling a station's antenna pattern through a directional control link
The use of a control link between a control point and a locally controlled station


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

A capacitive reactance
The same as the characteristic impedance of the line
An inductive reactance
The same as the input impedance to the final generator stage


Which type of digital mode does not support keyboard-to-keyboard operation?



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

Restrict both gain and Q
Restrict gain but increase Q
Restrict Q but increase gain
Increase both gain and Q


How does a diode detector function?

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


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?

Fewer components in the receiver
Reduced drift
Easier for front-end circuitry to eliminate image responses
Improved receiver noise figure


Which of the following describes how the loading and tuning capacitors are to be adjusted when tuning a vacuum tube RF power amplifier that employs a Pi-network output circuit?

The loading capacitor is set to maximum capacitance and the tuning capacitor is adjusted for minimum allowable plate current
The tuning capacitor is set to maximum capacitance and the loading capacitor is adjusted for minimum plate permissible current
The loading capacitor is adjusted to minimum plate current while alternately adjusting the tuning capacitor for maximum allowable plate current
The tuning capacitor is adjusted for minimum plate current, and the loading capacitor is adjusted for maximum permissible plate current


Which of the following is a requirement of a space station?

The space station must be capable of terminating transmissions by telecommand when directed by the FCC
The space station must cease all transmissions after 5 years
The space station must be capable of changing its orbit whenever such a change is ordered by NASA
All of these choices are correct


What is a crystal lattice filter?

A power supply filter made with interlaced quartz crystals
An audio filter made with four quartz crystals that resonate at 1kHz intervals
A filter with wide bandwidth and shallow skirts made using quartz crystals
A filter with narrow bandwidth and steep skirts made using quartz crystals


What is the National Radio Quiet Zone?

An area in Puerto Rico surrounding the Arecibo Radio Telescope
An area in New Mexico surrounding the White Sands Test Area
An area surrounding the National Radio Astronomy Observatory
An area in Florida surrounding Cape Canaveral


On which of the following frequencies is one likely to find FM ATV transmissions?

14.230 MHz
29.6 MHz
52.525 MHz
1255 MHz


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

They are bent toward the magnetic poles
Their polarization is randomly modified
They become elliptically polarized
They become phase-locked


What is meant by deviation ratio?

The ratio of the audio modulating frequency to the center carrier frequency
The ratio of the maximum carrier frequency deviation to the highest audio modulating frequency
The ratio of the carrier center frequency to the audio modulating frequency
The ratio of the highest audio modulating frequency to the average audio modulating frequency


What is the name of the diagram used to show the phase relationship between impedances at a given frequency?

Venn diagram
Near field diagram
Phasor diagram
Far field diagram


What is the primary purpose of a phasing line when used with an antenna having multiple driven elements?

It ensures that each driven element operates in concert with the others to create the desired antenna pattern
It prevents reflected power from traveling back down the feed line and causing harmonic radiation from the transmitter
It allows single-band antennas to operate on other bands
It makes sure the antenna has a low-angle radiation pattern


What is one advantage of using ASCII code for data communications?

It includes built in error correction features
It contains fewer information bits per character than any other code
It is possible to transmit both upper and lower case text
It uses one character as a shift code to send numeric and special characters


What is the purpose of the preselector in a communications receiver?

To store often-used frequencies
To provide a range of AGC time constants
To increase rejection of unwanted signals
To allow selection of the optimum RF amplifier device


What is the effect of aliasing in a digital or computer-based oscilloscope?

False signals are displayed
All signals will have a DC offset
Calibration of the vertical scale is no longer valid
False triggering occurs


Which of these choices is an acceptable method for monitoring the applicants if a VEC opts to conduct an exam session remotely?

Record the exam session on video tape for later review by the VE team
Use a real-time video link and the Internet to connect the exam session to the observing VEs
The exam proctor observes the applicants and reports any violations
Have each applicant sign an affidavit stating that all session rules were followed


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



What might be the cause of a loud roaring or buzzing AC line interference that comes and goes at intervals?

Arcing contacts in a thermostatically controlled device
A defective doorbell or doorbell transformer inside a nearby residence
A malfunctioning illuminated advertising display
All of these choices are correct


What might a sudden rise in radio background noise indicate?

A meteor ping
A solar flare has occurred
Increased transequatorial propagation likely
Long-path propagation is occurring


What is a depletion-mode FET?

An FET that exhibits a current flow between source and drain when no gate voltage is applied
An FET that has no current flow between source and drain when no gate voltage is applied
Any FET without a channel
Any FET for which holes are the majority carriers


In the antenna radiation pattern shown in Figure E9-1, what is the front-to-side ratio?

12 dB
14 dB
18 dB
24 dB
Circuit Diagram


What is meant by antenna bandwidth?

Antenna length divided by the number of elements
The frequency range over which an antenna satisfies a performance requirement
The angle between the half-power radiation points
The angle formed between two imaginary lines drawn through the element ends


What is reactive power?

Wattless, nonproductive power
Power consumed in wire resistance in an inductor
Power lost because of capacitor leakage
Power consumed in circuit Q


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?

An exponential rate of one
One time constant
One exponential period
A time factor of one


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

A Figure-8 broadside to the axis of the array
A Figure-8 end-fire along the axis of the array


What happens as the Q of an antenna increases?

SWR bandwidth increases
SWR bandwidth decreases
Gain is reduced
More common-mode current is present on the feed line


Which of the following is required for microwave propagation via rain scatter?

Rain droplets must be electrically charged
Rain droplets must be within the E layer
The rain must be within radio range of both stations
All of these choices are correct