3. Representation and transmission of information

Media for information transmission
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In this page, we are going to discuss about frequency band, its corresponding name, and usable services. You can see VLF. VLF (Very Low Frequency) is propagating along the earth’s surface, including over air and sea. In transmission, attenuation is small but sensitive to air noise, heat, and/or electricity. It is mainly used for marine communications or long distance radio navigation. LF (Low Frequency) is propagating along the earth’s surface. Attenuation is larger in daytime when the radio wave is absorbed through natural objects. It is mainly used for long distance radio navigation or as locators. MF (Middle Frequency) is propagating through the troposphere and absorbed through the ionosphere. It is mainly used for AM radio or marine radio broadcasting, and emergency frequency bands. HF (High Frequency) is propagating through the ionosphere. It is mainly used for amateur radio, as personal frequency bands, international broadcasting, telephones, telegraphs, etc. VHF (Very High Frequency) is propagating through line of sight (LOS). It is mainly used for VHF TV, FM radio, AM radio or location information in airplanes. UHF (Ultra High Frequency) is propagating through line of sight. It is mainly used for UHF TV, mobile phones, microwave links, etc. SHF (Super High Frequency) is propagating through line of sight or space. It is mainly used for satellite microwave or radar communications. EHF (Extreme High Frequency) is propagating through space. It is mainly used for radar, satellite, and scientific communications. Please click the button. You can see the electromagnetic spectra for communications in radio band.