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!


What is the most common method of reducing key clicks?

Increase keying waveform rise and fall times
Low-pass filters at the transmitter output
Reduce keying waveform rise and fall times
High-pass filters at the transmitter output


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 is the function of hysteresis in a comparator?

To prevent input noise from causing unstable output signals
To allow the comparator to be used with AC input signals
To cause the output to change states continually
To increase the sensitivity


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

30 or 60
60 or 100
128 or 256
180 or 360


What is the typical bandwidth of a properly modulated MFSK16 signal?

31 Hz
316 Hz
550 Hz
2.16 kHz


Which S parameter is equivalent to forward gain?



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

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


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

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


Which of the following test instruments is used to display spurious signals and/or intermodulation distortion products in an SSB transmitter?

A wattmeter
A spectrum analyzer
A logic analyzer
A time-domain reflectometer


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

6 meters and 2 meters
6 meters, 2 meters, and 1.25 meters
2 meters and 1.25 meters
2 meters


What might help to restore contact when DX signals become too weak to copy across an entire HF band a few hours after sunset?

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


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

An XOR gate
A flip-flop
An OR gate
A multiplexer


What is the term for the ratio between the frequency deviation of an RF carrier wave and the modulating frequency of its corresponding FM-phone signal?

FM compressibility
Quieting index
Percentage of modulation
Modulation index


What is meant by the radiation resistance of an antenna?

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


How are the wavelength scales on a Smith chart calibrated?

In fractions of transmission line electrical frequency
In fractions of transmission line electrical wavelength
In fractions of antenna electrical wavelength
In fractions of antenna electrical frequency


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


What does VOACAP software model?

AC voltage and impedance
VHF radio propagation
HF propagation
AC current and impedance


What is the main reason to use a charge controller with a solar power system?

Prevention of battery undercharge
Control of electrolyte levels during battery discharge
Prevention of battery damage due to overcharge
Matching of day and night charge rates


What is the packaging technique in which leadless components are soldered directly to circuit boards?

Direct soldering
Virtual lead mounting
Stripped lead
Surface mount


Which of these materials is affected the most by photoconductivity?

A crystalline semiconductor
An ordinary metal
A heavy metal
A liquid semiconductor


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



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

704 W
355 W
252 W
1.42 mW


Which point on Figure E5-2 best represents the impedance of a series circuit consisting of a 300 ohm resistor and a 19 picofarad capacitor at 21.200 MHz?

Point 1
Point 3
Point 7
Point 8
Circuit Diagram


What is the definition of symbol rate in a digital transmission?

The number of control characters in a message packet
The duration of each bit in a message sent over the air
The rate at which the waveform of a transmitted signal changes to convey information
The number of characters carried per second by the station-to-station link


How can an oscillator's microphonic responses be reduced?

Use of NP0 capacitors
Eliminating noise on the oscillator's power supply
Using the oscillator only for CW and digital signals
Mechanically isolating the oscillator circuitry from its enclosure


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


Who may be the control operator of an auxiliary station?

Any licensed amateur operator
Only Technician, General, Advanced or Amateur Extra Class operators
Only General, Advanced or Amateur Extra Class operators
Only Amateur Extra Class operators


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


For what portion of a signal cycle does a Class AB amplifier operate?

More than 180 degrees but less than 360 degrees
Exactly 180 degrees
The entire cycle
Less than 180 degrees


What is the relationship between the current through an inductor and the voltage across an inductor?

Voltage leads current by 90 degrees
Current leads voltage by 90 degrees
Voltage and current are 180 degrees out of phase
Voltage and current are in phase


Which semiconductor material contains excess holes in the outer shell of electrons?



What does the abbreviation NEC stand for when applied to antenna modeling programs?

Next Element Comparison
Numerical Electromagnetic Code
National Electrical Code
Numeric Electrical Computation


What core material property determines the inductance of a toroidal inductor?

Thermal impedance


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

Decrease the RF bandwidth of the receiver
Raise the receiver IF frequency
Increase the receiver front end gain
Switch from fast AGC to slow AGC


What do the letters I and Q in I/Q Modulation represent?

Inactive and Quiescent
Instantaneous and Quasi-stable
Instantaneous and Quenched
In-phase and Quadrature


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



What is a common use for point contact diodes?

As a constant current source
As a constant voltage source
As an RF detector
As a high voltage rectifier


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?

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


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

An SWR less than 1:1
A reflection coefficient greater than 1
A dielectric constant greater than 1
An SWR greater than 1:1


Which amateur stations may be operated under RACES rules?

Only those club stations licensed to Amateur Extra class operators
Any FCC-licensed amateur station except a Technician class
Any FCC-licensed amateur station certified by the responsible civil defense organization for the area served
Any FCC-licensed amateur station participating in the Military Auxiliary Radio System (MARS)


What happens to the radiation pattern of an unterminated long wire antenna as the wire length is increased?

The lobes become more perpendicular to the wire
The lobes align more in the direction of the wire
The vertical angle increases
The front-to-back ratio decreases


What type of modulation is used for JT65 contacts?

Multi-tone AFSK
IEEE 802.11


What is the primary function of an external earth connection or ground rod?

Reduce received noise
Lightning protection
Reduce RF current flow between pieces of equipment
Reduce RFI to telephones and home entertainment systems


What is transequatorial propagation?

Propagation between two mid-latitude points at approximately the same distance north and south of the magnetic equator
Propagation between any two points located on the magnetic equator
Propagation between two continents by way of ducts along the magnetic equator
Propagation between two stations at the same latitude


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

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


Which of the following statements concerning remotely controlled amateur stations is true?

Only Extra Class operators may be the control operator of a remote station
A control operator need not be present at the control point
A control operator must be present at the control point
Repeater and auxiliary stations may not be remotely controlled


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

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


What is the function of a sense antenna?

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


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


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