Radio and Electronics (DED Philippinen, 66 p.): 4. RADIOWAVES: (introduction...)

Radio and Electronics (DED Philippinen, 66 p.)

4. RADIOWAVES

		*(introduction...)*
		4.1. ORIGIN OF RADIOWAVES
		4.2. PARAMETERS OF ELECTROMAGNETIC WAVES
		4.3. PROPAGATION OF RADIOWAVES
		4.4. SPECTRUM OF RADIOWAVES AND BANDS OF RADIOWAVES

(introduction...)

While with telephonsystems the medium of “transport” for the signal was an electric current on a wire, you know that radios don't get their signal by a wire. The medium used here are the so called ELECTROMAGNETIC WAVES and from the huge overall range of electromagnetic waves (10-10¹⁵Hz) the SPECTRUM called the RADIOWAVES uses (10⁵-10¹⁰Hz).

Before we can go on to talk about the devices of transmitting and receving these radiowaves, we have to know the basics of them.