Personal radio service

A personal radio service is any system that allows individual to operate radio transmitters and receivers for personal purposes with minimal or no special license or individual authorization. Personal radio services exist around the world and typically use light-weight walkie talkie portable radios. The power output, antenna size, and technical characteristics of the equipment are set by regulations in each country. Many regions (for example, the European Union) have standardized personal radio service rules to allow travelers from one country to use their equipment in another country. Examples of standardized services include PMR446 and FM Citizens Band Radio (CB) in the EU and several other countries/regions. 26–27 MHz CB radio is the oldest personal radio service and is used in nearly every country worldwide, with many countries and regions copying the United States 40-channel frequency plan. In many countries, CB radio is less popular due to the availability of other personal radio services that offer shorter antennas, better protection from noise and interference.

Because radio spectrum allocation varies around the world, a personal radio service device may not be usable outside its original area of purchase. For example, US-specification Family Radio Service radios operate on frequencies that in Europe are allocated to fire and emergency services. Operation of a personal radio device that cause interference to other services may result in prosecution. Some personal radio service frequency plans are regionally accepted, for example, the European PMR446 system is available in many countries, and the American FRS/GMRS system's channel plans have been adopted by Canada, Mexico and some countries in South America.

Specific details vary between the different national services, but many personal radio services operate in the VHF or UHF part of the radio spectrum, using frequency modulation and a maximum power of only a few watts. Operation is on predetermined channels. Unlike commercial business, marine, aviation, or emergency services radio, all users in an area share access to the available channels, requiring cooperation for effective communications. Unlike amateur radio, experimentation with different types of apparatus, and modes of modulation is not permitted, and equipment must be factory-built and approved. Many of these services require non-removable antennas or place restrictions on antenna size, height or gain. The high-VHF band (137–174 MHz) and UHF bands (325, 350, 400–480, 900 MHz) are the most popular aside from the 25–28 MHz "HF CB" bands. There are notable exceptions to this, including the 78 MHz and 245 MHz Thai "CB 78" and "CB 245" VHF-FM bands, the 68–71 MHz Finnish band, the 30–31 MHz Swedish "Hunting Radio" band, and the 43 MHz Italian "VHF CB" bands. The lower frequency allocations (especially the 30/31 and 43 MHz bands) often exhibit propagation and communication range characteristics similar to 27 MHz CB radio. Higher frequencies (especially above 200 MHz) are almost exclusively line-of-sight.

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