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1、RF from DC to Light,For science, fun and profit,RF from DC to Light,The RF Spectrum is full of all kinds of things: - The sounds of nature, lighting from thunder storms, meteors entering the earth atmosphere, earth quakes, and the solar wind impacting on the earths ionosphere. - Communications, one
2、on one or one to many. - Sensors liker radar, radiosondes, etc.,RF from DC to Light,Measurement is done by an expression of frequency, we use the unit of Hertz named after German physicist Heinerich Hertz (1857 to 1894). It replaced an older term “cycles per second” in 1960. Hertz, Kilohertz, Megahe
3、rtz, Gigahertz, and Terahertz.,RF from DC to Light,Radio Propagation: - Surface wave or ground wave, follows the surface of the earth, goes through water. -Direct wave or line-of-sight -Ionospheric wave or sky wave reflected by some part of the earths ionosphere many sub modes (Auroral reflection, S
4、poradic-E),RF from DC to Light,FCC Federal Communications Commission The people who control the RF Spectrum in the US. World Radiocommunications Conference (WRC) , meets at 2 to 4 year intervals.,RF from DC to Light,Regulations - FCC Part 15 (low power communications) Wireless Data, Cordless Phones
5、etc. - FRS/GMRS (Family Radio Service/General Mobil Radio Service). - HAM Radio - Broadcast Radio (AM, FM, TV etc.),RF from DC to Light,Bands -ELF 3 - 30 HZ, 100 - 10 Mm, Extremely low frequency -SLF 30 - 300 Hz, 10 - 1 Mm, Super low frequency -ULF 300 3000 Hz, 1000 -100 km, Ultra low frequency -VLF
6、 3 30 kHz, 100 10 km, Very low frequency -LF 30-300 kHz 10-1 km, Low Frequency -MF 300-3000 kHz 1000-100 m Medium Frequency,RF from DC to Light,Bands (continued) -HF 3-30 MHz 100-10 m High Frequency -VHF 30-300 MHz 10-1m Very high frequency -UHF 300-3000 MHz 100-10 cm Ultra high frequency -SHF 3-300
7、 GHz 10-1 cm Super High Frequency -EHF 30-300 GHz 10-1 mm Extremely high frequency Reference: http:/en.wikipedia.org/wiki/Radio_frequency,RF from DC to Light,Letter Band (UHF, SHF & EHF): L band 1-2 GHz30-15 cm S band 2-4 GHz15-7.5 cm C band 4-8 GHz3.8-2.5 cm X band 8-12 GHz2.5-1.7 cm Ku band 12to18 GHz1.7-1.1 cm Ka band 27-40 GHz1.1-0.75 cm V band 40-75 GHz0.75-0.40 cm W band75-110 GHz0.40-0.27 cm(History Note),