training course on weather radar systems - RTC, Regional Training ...

MODULE A- INTRODUCTION TO RADAR
3. PROPOGATION OF EM WAVES
Radar signals are emitted in some frequencies within the electromagnetic spectrum located in a
range from a few MHz to 600 GHz. First let us review the electromagnetic spectrum.
3. 1. Electromagnetic Spectrum
All things (which have temperature above absolute zero) emit radiation. Radiation is energy that
travels in the form of waves. Since radiation waves have electrical and magnetic properties, they
are called as “electromagnetic waves”.
Most of the electromagnetic energy on the earth originates from the sun. The sun actually
radiates electromagnetic energy at several different wavelengths and frequencies, ranging from
gamma rays to radio waves. Collectively, these wavelengths and frequencies make up the
electromagnetic spectrum.
Figure -3.1
Frequency and wavelength of electromagnetic waves change with inverse of other. According to
the famous formula about light, then f can be calculated as follows:
λ=c/f " f= c/λ " T = 1 / f [s] " λ = c/f = 299,792,458 / f [m] (f in Hz [s -1 ])
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TURKEY RADAR TRAINING 1.0 / ALANYA 2005