Radio

AM radio waves are Amplitude Modulation, these use signal strength of variation. FM radio waves are Frequency Modulation, these encode sound (i.e.: radio broadcast) or pictures (i.e.: TV) through a variation in wavelength of a carrier signal.

Early radio broadcasts were transmitted through what we call today long waves. The more modern radio communication is now using the fact that radio waves vibrate at a certain rate, and there are Very High Frequency (VHF) transmissions as well as Ultra High Frequency (UHF) transmissions. These are both used for television and they are both FM radio waves, whereas the earlier transmissions were AM radio waves.

High frequency radio waves do not travel through water, therefore submarines use Extremely Low Frequency (ELF) and other low frequency transmissions rather than FM radio waves. They used to use AM radio waves communicating to aircraft above them.

 

 

 

 

 

|Title|Introduction|Wave|Light|Heat|Radio|Bibliography|Related Sites|