SET 1 ECT Flashcards
What is the name for the distance a radio wave travels during one complete cycle?
Wavelength
How fast does a radio wave travel through free space?
At the speed of light
How does the wavelength of a radio wave relate to its frequency?
The wavelength gets shorter as the frequency increases
What is the formula for converting frequency to wavelength in meters?
Wavelength in meters equals 300 divided by frequency in megahertz
What property of radio waves is often used to identify the different frequency bands?
The approximate wavelength
What are the frequency limits of the UHF spectrum?
300 to 3000 MHz
What are the frequency limits of the VHF
30 to 300 MHz
What are the frequency limits of the VHF
30 to 300 MHz
What are the frequency limits of the UHF
300 to 3000 MHz
What frequency range is referred to as HF?
3 to 30 MHz
What is the approximate velocity of a radio wave as it travels through free space?
300,000,000 meters per second
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 one-millionth 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 3000- milliampere current, what reading would it show?
3 amperes
a frequency readout calibrated in megahertz shows a reading of3.525 MHz, what would it show if it were calibrated in kilohertz?
3525 kHz
What happens when the deviation of an FM transmitter is increased?
Its signal occupies more bandwidth
How many microfarads are 1,000,000 picofarads?
1 microfarad
What is the unit of frequency?
Hertz
What is the abbreviation that refers to radio frequency signals of all types?
RF
What determines the amount of deviation of an FM(as opposed to PM) signal?
The amplitude of the modulating signal
Which of the following is a form of amplitude modulation?
Single sideband
What type of modulation is most commonly used for VHF packet radio transmissions?
SSB
Which type of voice modulation is most often used for long- distance or weak signal contacts on the VHF and UHF bands?
SSB
Which type of modulation is most commonly used for VHF and UHF voice repeaters?
FM
Which of the following types of emission has the narrowest bandwidth?
CW()
Which sideband is normally used for 10 meter HF, VHF and UHF single-sideband communications?
Upper sideband
What is the primary advantage of single sideband over FM for voice transmissions?
SSB signals have narrower bandwidth ()
What is the approximate bandwidth of a single sideband voice signal?
3kHz
What is the approximate bandwidth of a VHF repeater FMphone signal?
Between 5 and 15 kHz
What is the typical bandwidth of analog fast-scan TV transmissions on the 70 cm band?
About 6 MHz
What is the approximate maximum bandwidth required to transmit a CW signal?
150Hz
What type of amateur station simultaneously retransmits the signal of another amateur station on a different channel or channels?
Repeater station
What could be used in place of a regular speaker to help you copy signals in a noisy area?
A set of headphones
What term describes the number of times per second that an alternating current reverses direction?
Frequency
Electrical current is measured in which of the following units?
Amperes
Electrical power is measured in which of the following units?
watts
Which term describes the rate at which electrical energy is used?
Power
What is the name for the flow of electrons in an electric circuit?
Current
What is the basic unit of electromotive force?
The volt
What is the name for a current that flows only in one direction?
Direct current
What is the formula used to calculate electrical power in a DC circuit?
Power (P) equals voltage (E) multiplied by current (I)
What is the electrical term for the electromotive force (EMF) that causes electron flow?
Voltage
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
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
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)