
What causes "tropospheric ducting"?
Temperature inversions in the atmosphere

What is generally the best time for longdistance 10 meter band propagation?
During daylight hours

What is the radio horizon?
The distance at which radio signals between two points are effectively blocked by the curvature of the Earth

Why do VHF and UHF radio signals usually travel somewhat farther than the visual line of sight distance between two stations?
The Earth seems less curved to radio waves than to light

Which of the following is true concerning the microphone connectors on amateur transceivers?
Some connectors include pushtotalk and voltages for powering the microphone

What could be used in place of a regular speaker to help you copy signals in a noisy area?
A set of headphones

Which is a good reason to use a regulated power supply for communications equipment?
It prevents voltage fluctuations from reaching sensitive circuits

Where must a filter be installed to reduce harmonic emissions?
Between the transmitter and the antenna

What type of filter should be connected to a TV receiver as the first step in trying to prevent RF overload from a nearby 2 meter transmitter?
Bandreject filter

Which of the following would be connected between a transceiver and computer in a packet radio station?
Terminal node controller

How is the computer’s sound card used when conducting digital communications using a computer?
The sound card provides audio to the microphone input and converts received audio to digital form

Which type of conductor is best to use for RF grounding?
Flat strap

Which would you use to reduce RF current flowing on the shield of an audio cable?
Ferrite choke

What is the source of a highpitched whine that varies with engine speed in a mobile transceiver’s receive audio?
The alternator

Where should a mobile transceiver’s power negative connection be made?
At the battery or engine block ground strap

What may happen if a transmitter is operated with the microphone gain set too high?
The output signal might become distorted

Which of the following can be used to enter the operating frequency on a modern transceiver?
The keypad or VFO knob

What is the purpose of the squelch control on a transceiver?
To mute receiver output noise when no signal is being received

What is a way to enable quick access to a favorite frequency on your transceiver?
Store the frequency in a memory channel

Which of the following would reduce ignition interference to a receiver?
Turn on the noise blanker

Which of the following controls could be used if the voice pitch of a singlesideband signal seems too high or low?
The receiver RIT or clarifier

What does the term "RIT" mean?
Receiver Incremental Tuning

What is the advantage of having multiple receive bandwidth choices on a multimode transceiver?
Permits noise or interference reduction by selecting a bandwidth matching the mode

Which of the following is an appropriate receive filter to select in order to minimize noise and interference for SSB reception?
2400 Hz

Which of the following is an appropriate receive filter to select in order to minimize noise and interference for CW reception?
500 Hz

Which of the following describes the common meaning of the term "repeater offset"?
The difference between the repeater’s transmit and receive frequencies

Electrical current is measured in which of the following units?
Amperes

Electrical power is measured in which of the following units?
Watts

What is the name for the flow of electrons in an electric circuit?
Current

What is the name for a current that flows only in one direction?
Direct current

What is the electrical term for the electromotive force (EMF) that causes electron flow?
Voltage

How much voltage does a mobile transceiver usually require?
About 12 volts

Which of the following is a good electrical conductor?
Copper

Which of the following is a good electrical insulator?
Glass

What is the name for a current that reverses direction on a regular basis?
Alternating current

Which term describes the rate at which electrical energy is used?
Power

What is the basic unit of electromotive force?
The volt

How many milliamperes is 1.5 amperes?
1,500 milliamperes

What is another way to specify a radio signal frequency of 1,500,000 hertz?
1500 kHz

How many volts are equal to one kilovolt?
One thousand volts

How many volts are equal to one microvolt?
One onemillionth of a volt

Which of the following is equivalent to 500 milliwatts?
0.5 watts

If an ammeter calibrated in amperes is used to measure a 3000milliampere current, what reading would it show?
3 amperes

If a frequency readout calibrated in megahertz shows a reading of 3.525 MHz, what would it show if it were calibrated in kilohertz?
3525 kHz

How many microfarads are 1,000,000 picofarads?
1 microfarad

What is the approximate amount of change, measured in decibels (dB), of a power increase from 5 watts to 10 watts?
3 dB

What is the approximate amount of change, measured in decibels (dB), of a power decrease from 12 watts to 3 watts?
6 dB

What is the approximate amount of change, measured in decibels (dB), of a power increase from 20 watts to 200 watts?
10 dB

What is the ability to store energy in an electric field called?
Capacitance

What is the basic unit of capacitance?
The farad

What is the ability to store energy in a magnetic field called?
Inductance

What is the basic unit of inductance?
The henry

What is the unit of frequency?
Hertz

What is the abbreviation that refers to radio frequency signals of all types?
RF

What is the usual name for electromagnetic waves that travel through space?
Radio waves

What is the formula used to calculate electrical power in a DC circuit?
Power (P) equals voltage (E) multiplied by current (I)

How much power is being used in a circuit when the applied voltage is 13.8 volts DC and the current is 10 amperes?
138 watts

How much power is being used in a circuit when the applied voltage is 12 volts DC and the current is 2.5 amperes?
30 watts

How many amperes are flowing in a circuit when the applied voltage is 12 volts DC and the load is 120 watts?
10 amperes

What formula is used to calculate current in a circuit?
Current (I) equals voltage (E) divided by resistance (R)

What formula is used to calculate voltage in a circuit?
Voltage (E) equals current (I) multiplied by resistance (R)

What formula is used to calculate resistance in a circuit?
Resistance (R) equals voltage (E) divided by current (I)

What is the resistance of a circuit in which a current of 3 amperes flows through a resistor connected to 90 volts?
30 ohms

What is the resistance in a circuit for which the applied voltage is 12 volts and the current flow is 1.5 amperes?
8 ohms

What is the resistance of a circuit that draws 4 amperes from a 12volt source?
3 ohms

What is the current flow in a circuit with an applied voltage of 120 volts and a resistance of 80 ohms?
1.5 amperes

What is the current flowing through a 100ohm resistor connected across 200 volts?
2 amperes

What is the current flowing through a 24ohm resistor connected across 240 volts?
10 amperes

What is the voltage across a 2ohm resistor if a current of 0.5 amperes flows through it?
1 volt

What is the voltage across a 10ohm resistor if a current of 1 ampere flows through it?
10 volts

What is the voltage across a 10ohm resistor if a current of 2 amperes flows through it?
20 volts

