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ITU Radio Band SymbolsUHF and VHF are the most commonly used frequency bands for transmission of television signals. Modern mobile phones also transmit and receive within the UHF spectrum. UHF is widely used by public service agencies for two-way radio communication, usually using narrowband frequency modulation, but digital services are on the rise. Narrowband radio modems use UHF and VHF frequencies for long range data communications e.g. for supervision and control of power distribution networks and other SCADA and automation applications. There has traditionally been very little radio broadcasting in this band until recently; see digital audio broadcasting for details. The Global Positioning System also uses UHF.
One uncommon use of UHF waves is for the detection of partial discharges. Partial discharges occur because of the sharp geometries created in high voltage insulated equipment. The advantage of UHF detection is that this method can be used to localize the source of the discharge. A drawback to UHF detection is the extreme sensitivity to external noise. UHF detection methods are used in the field, especially for large distribution transformers.
2.45 GHz, now mainly used for WiFi, Bluetooth and US cordless phones has been proposed for Wireless energy transfer. Some pilot experiments have been performed, but it is not used on a large scale.
