n required because operators usually publish "footprint" maps showing the received power contours in dBW, taking into account the path loss and the radiation pattern of the satellite transmitting antenna. Conclusion Radio wave propagation uses frequencies of up to 100 GHz and higher. The following sec- tions subdivide the frequency range into broadbands and summarize their areas of application. VLF and LF: 10 to 300 kHz This range is for long-distance (greater than 1000-km) ground wave transmission and is used for communications and radio navigation. Propagation is unaffected by ionospheric conditions. High-power and large antennas are required, and there is very limited spectrum availability. MF: 300 kHz to 3 MHz This range is for medium- to short-distance (up to 1000-km) ground wave transmission and is used for sound broadcasting and mobile communications. Propagation is little affected by ionospheric conditions, but nighttime interference can be a problem. HF: 3 to 30 MHz Worldwide communications use comparatively low power (1 kw), but they are heavily dependent on ionospheric conditions. There is limited channel availability, and it is Chapter 8 Radio Wave Propagation used for sound broadcasting, point-to-point, and mobile maritime and aeronautical communications. VHF and UHF: 30 MHz to 1 GHz Officially, UHF extends to 3 GHz. Lower frequencies are affected by anomalous propagation conditions. UHF is used for line-of-sight communications, typically 80 km (meteor scatter on 50 MHz can provide services up to 2000 km), and multichannel point-to-point commu- nications, FM sound, and TV broadcasting and mobile communications. Microwave: 1 to 30 GHz Microwaves are unaffected by ionospheric conditions, but there is some attenuation at higher frequencies because of rain. They are used for line-of-sight communications, typically of 50 km (tropospheric scatter can provide services up to 500 km). Satellite services provide worldwide coverage. Wideband multichannel communication is available. Microwaves are extensively us