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 a folded dipole antenna?

A dipole one-quarter wavelength long
A type of ground-plane antenna
A half-wave dipole with an additional parallel wire connecting its two ends
A dipole configured to provide forward gain


Which of these digital modes has the narrowest bandwidth?

170 Hz shift, 45-baud RTTY
300-baud packet


What are the two families of circles and arcs that make up a Smith chart?

Resistance and voltage
Reactance and voltage
Resistance and reactance
Voltage and impedance


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 one way a single-sideband phone signal can be generated?

By using a balanced modulator followed by a filter
By using a reactance modulator followed by a mixer
By using a loop modulator followed by a mixer
By driving a product detector with a DSB signal


What describes Orthogonal Frequency Division Multiplexing?

A frequency modulation technique that uses non-harmonically related frequencies
A bandwidth compression technique using Fourier transforms
A digital mode for narrow-band, slow-speed transmissions
A digital modulation technique using subcarriers at frequencies chosen to avoid intersymbol interference


How many different input levels can be encoded by an analog-to-digital converter with 8-bit resolution?

8 multiplied by the gain of the input amplifier
256 divided by the gain of the input amplifier


Amateur stations may not transmit in which of the following frequency segments if they are located in the contiguous 48 states and north of Line A?

440 MHz - 450 MHz
53 MHz - 54 MHz
222 MHz - 223 MHz
420 MHz - 430 MHz


What is the definition of telemetry?

One-way transmission of measurements at a distance from the measuring instrument
Two-way transmissions in excess of 1000 feet
Two-way transmissions of data
One-way transmission that initiates, modifies, or terminates the functions of a device at a distance


What information is contained in the lookup table of a direct digital synthesizer (DDS)?

The phase relationship between a reference oscillator and the output waveform
Amplitude values that represent the desired waveform
The phase relationship between a voltage-controlled oscillator and the output waveform
Frequently used receiver and transmitter frequencies


How does the spread spectrum technique of frequency hopping work?

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


Which point in Figure E5-1 best represents the impedance of a series circuit consisting of a 300-ohm resistor and an 18-microhenry inductor at 3.505 MHz?

Point 1
Point 3
Point 7
Point 8
Circuit Diagram


Which of the following is a good technique for making meteor scatter contacts?

15-second timed transmission sequences with stations alternating based on location
Use of special digital modes
Short transmissions with rapidly repeated call signs and signal reports
All these choices are correct


Which of these emission modes is best for auroral propagation?



What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 100 ohms, R is 100 ohms, and XL is 75 ohms?

14 degrees with the voltage lagging the current
14 degrees with the voltage leading the current
76 degrees with the voltage leading the current
76 degrees with the voltage lagging the current


What is the elevation angle of peak response in the antenna radiation pattern shown in Figure E9-2?

45 degrees
75 degrees
7.5 degrees
25 degrees
Circuit Diagram


How much does the gain of an ideal parabolic dish antenna change when the operating frequency is doubled?

2 dB
3 dB
4 dB
6 dB


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

Ball grid array


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

Approximately halfway between saturation and cutoff
Where the load line intersects the voltage axis
At a point where the bias resistor equals the load resistor
At a point where the load line intersects the zero bias current curve


Why are there separate electric (E) and magnetic (H) field MPE limits?

The body reacts to electromagnetic radiation from both the E and H fields
Ground reflections and scattering make the field strength vary with location
E field and H field radiation intensity peaks can occur at different locations
All these choices are correct


Which of the following factors determines ground losses for a ground-mounted vertical antenna operating in the 3 MHz to 30 MHz range?

The standing wave ratio
Distance from the transmitter
Soil conductivity
Take-off angle


How much power is being absorbed by the load when a directional power meter connected between a transmitter and a terminating load reads 100 watts forward power and 25 watts reflected power?

100 watts
125 watts
25 watts
75 watts


How does a narrow-band roofing filter affect receiver performance?

It improves sensitivity by reducing front end noise
It improves intelligibility by using low Q circuitry to reduce ringing
It improves dynamic range by attenuating strong signals near the receive frequency
All these choices are correct


Which of the following limits the highest frequency signal that can be accurately displayed on a digital oscilloscope?

Sampling rate of the analog-to-digital converter
Amount of memory
Q of the circuit
All these choices are correct


What does the 304A solar parameter measure?

The ratio of x-ray flux to radio flux, correlated to sunspot number
UV emissions at 304 angstroms, correlated to the solar flux index
The solar wind velocity at 304 degrees from the solar equator, correlated to solar activity
The solar emission at 304 GHz, correlated to x-ray flare levels


What is a Programmable Logic Device (PLD)?

A logic circuit that can be modified during use
A programmable collection of logic gates and circuits in a single integrated circuit
Programmable equipment used for testing digital logic integrated circuits
A type of transistor whose gain can be changed by digital logic circuits


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


At what time of year is sporadic E propagation most likely to occur?

Around the solstices, especially the summer solstice
Around the solstices, especially the winter solstice
Around the equinoxes, especially the spring equinox
Around the equinoxes, especially the fall equinox


What hardware, other than a receiver with SSB capability and a suitable computer, is needed to decode SSTV using Digital Radio Mondiale (DRM)?

A special IF converter
A special front end limiter
A special notch filter to remove synchronization pulses
No other hardware is needed


What will be the output voltage of the circuit shown in Figure E7-3 if R1 is 1000 ohms, RF is 10,000 ohms, and 0.23 volts DC is applied to the input?

0.23 volts
2.3 volts
-0.23 volts
-2.3 volts
Circuit Diagram


Which of the following carrier frequencies is illegal for LSB AFSK emissions on the 17 meter band RTTY and data segment of 18.068 to 18.110 MHz?

18.068 MHz
18.100 MHz
18.107 MHz
18.110 MHz


What is the maximum permissible duration of a remotely controlled station's transmissions if its control link malfunctions?

30 seconds
3 minutes
5 minutes
10 minutes


Which materials are commonly used as a core in an inductor?

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


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

Reverse bias
Forward bias
Zero bias
Inductive bias


How can radio frequency interference from an AC motor be suppressed?

By installing a high-pass filter in series with the motor's power leads
By installing a brute-force AC-line filter in series with the motor leads
By installing a bypass capacitor in series with the motor leads
By using a ground-fault current interrupter in the circuit used to power the motor


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

23.5 MHz
23.5 kHz
7.12 kHz
7.12 MHz


Why should effective radiated power to a satellite that uses a linear transponder be limited?

To prevent creating errors in the satellite telemetry
To avoid reducing the downlink power to all other users
To prevent the satellite from emitting out-of-band signals
To avoid interfering with terrestrial QSOs


What feature of a cardioid pattern antenna makes it useful for direction finding?

A very sharp peak
A very sharp single null
Broadband response
High radiation angle


Which of these choices is an effective way to match an antenna with a 100-ohm feed point impedance to a 50-ohm coaxial cable feed line?

Connect a 1/4-wavelength open stub of 300-ohm twinlead in parallel with the coaxial feed line where it connects to the antenna
Insert a 1/2 wavelength piece of 300-ohm twinlead in series between the antenna terminals and the 50-ohm feed cable
Insert a 1/4-wavelength piece of 75-ohm coaxial cable transmission line in series between the antenna terminals and the 50-ohm feed cable
Connect a 1/2 wavelength shorted stub of 75-ohm cable in parallel with the 50-ohm cable where it attaches to the antenna


What impedance does a 1/4-wavelength transmission line present to a generator when the line is shorted at the far end?

Very high impedance
Very low impedance
The same as the characteristic impedance of the transmission line
The same as the generator output impedance


Which of the following factors has the greatest effect on the bandwidth and response shape of a crystal ladder filter?

The relative frequencies of the individual crystals
The DC voltage applied to the quartz crystal
The gain of the RF stage preceding the filter
The amplitude of the signals passing through the filter


What is the equation for calculating power dissipated by a series linear voltage regulator?

Input voltage multiplied by input current
Input voltage divided by output current
Voltage difference from input to output multiplied by output current
Output voltage multiplied by output current


Why is an anti-aliasing digital filter required in a digital decimator?

It removes high-frequency signal components that would otherwise be reproduced as lower frequency components
It peaks the response of the decimator, improving bandwidth
It removes low-frequency signal components to eliminate the need for DC restoration
It notches out the sampling frequency to avoid sampling errors


What is the power factor of an RL circuit having a 30-degree phase angle between the voltage and the current?



What is the name given to an impurity atom that adds holes to a semiconductor crystal structure?

Insulator impurity
N-type impurity
Acceptor impurity
Donor impurity


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 signals outside the desired band
To allow selection of the optimum RF amplifier device


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

Minimum passing score of 70%
Minimum passing score of 74%
Minimum passing score of 80%
Minimum passing score of 77%


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 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)


Which of the following frequencies are sometimes used for amateur radio mesh networks?

HF frequencies where digital communications are permitted
Frequencies shared with various unlicensed wireless data services
Cable TV channels 41 through 43
The 60 meter band channel centered on 5373 kHz