Saturday, May 31, 2014

Frequency and Wavelength

If you know a radio wave’s frequency, you can figure out the wavelength because the speed of light 300,000,000 ( kilometers per second), is always the same. Here’s how:

Wavelength = Speed of light / Frequency of the wave Wavelength in meters = 300,000,000 / Frequency in hertz

Frequency in hertz = 300,000,000 / Wavelength in meters
Frequency is abbreviated as f, the speed of light as c, and wavelength as the Greek letter lambda, λ, leading to the following simple equations:

f = c / λ and λ = c / f

Examples:   300,000,000 (c) /1800 kHz (f) =166 Meters
                    300,000,000 (c) /148,000 MHz (f) =2 Meters
                    300,000,000 (c) /50.000 MHz (f) =6 Meters

Radio waves oscillate at frequencies between a few hundred kilohertz, or kHz
(kilo is the metric abbreviation meaning 1,000), up to 1,000 gigahertz, or GHz
(giga is the metric abbreviation meaning 1 billion). They have corresponding
wavelengths from hundreds of meters at the low frequencies to a fraction of a
millimeter (mm) at the high frequencies. The most convenient two units to use in thinking of radio wave frequency (RF) and wavelength are megahertz (MHz; mega means 1 million) and meters (m).

f = 300 / λ in m and λ = 300 / f in MHz

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