Lesson 7 Flashcards
Basic Concepts of Radio Waves
Radio waves travel at the speed of light in free space, which is
300 million meters per second!
The two components of a radio wave are the
electric and magnetic fields
What is the velocity of a radio wave traveling through free space?
At the speed of light
In addition to frequency, which of the following is used to identify amateur radio bands?
The approximate wavelength in meters
What is the approximate velocity of a radio wave in free space?
300,000,000 meters per second
Why is the radio horizon for VHF and UHF signals more distant than the visual horizon?
The atmosphere refracts radio waves slightly
What weather condition might decrease range at microwave frequencies?
Precipitation
What property of a radio wave defines its polarization?
The orientation of the electric field
What happens when antennas at opposite ends of a VHF or UHF line of sight radio link are not using the same polarization?
Received signal strength is reduced
What antenna polarization is normally used for long-distance weak-signal CW and SSB contacts on the VHF and UHF bands?
Horizontal
What are the two components of a radio wave?
Electric and magnetic fields
What frequency range is referred to as UHF?
300 to 3000 MHz
What is the relationship between wavelength and frequency?
The wavelength gets shorter as the frequency increases
What is the formula for converting frequency to approximate wavelength in meters?
Wavelength in meters equals 300 divided by frequency in megahertz
What is the effect of vegetation on UHF and microwave signals?
Absorption
