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Sources of high frequency fields

Numerous technologies use high frequency (HF) electromagnetic fields: Every day life cannot be imagined without broadcasting and television, cordless phones increase comfort when phoning indoors and in the garden, babies are monitored in their rooms using baby monitors, computers are linked to each other and to peripheral devices by using Wireless LAN (WLAN) and Bluetooth and recently ultrawideband (UWB) technologies, police and fire brigades use their own radio network for communication. Wireless transmission of information and mobile communications are a matter of course nowadays.

Information on mobile communication can be found on Radiation protection in mobile communications.

Woman on Cordless DECT landline telephone

Cordless landline telephones

Cordless telephones transmit conversations between a base station connected to the telephone landline and a portable talk/listen device (handset) via radio. In Germany, now only devices that use the DECT standard (Digital Enhanced Cordless Telecommunications) devices may be operated.

Types of wireless headphones

Wireless in-ear headphones

Wireless in-ear headphones are inserted directly into the ear canal and transmit sound signals by radio through weak high-frequency electromagnetic fields.

woman in the kitchen operatin a microwave oven

Microwave ovens

Microwave ovens use high-frequency electromagnetic fields with a frequency of 2.45 gigahertz to heat food up quickly. These high-frequency fields are produced inside the appliances.

Broadcasting station

Radio and television

Broadcasting stations transmit at frequencies between 150 kilohertz and several hundred megahertz. The number of stations is low compared to mobile telecommunication. Transmitter power, however, can be very high, up to several million watt (MW) depending on the size of the coverage area and on the frequency range.

Radar on a ship

Radar systems

Radar systems are used in a large variety of places and a wide range of applications, for example in civil and military air surveillance, on ships, in weather observations, in road traffic monitoring, in vehicle driver assistance systems, such as adaptive cruise control and emergency brake assist, in level measurement systems for liquid tanks or bulk storage silos. The frequencies used range from 1 to 100 gigahertz.

Router on a desk. Woman in the background sitting on a couch

Bluetooth, Wireless Local Area Networks (WLAN), and Ultrawideband (UWB)

Bluetooth, Wireless Local Area Networks (WLAN), and Ultrawideband (UWB) apply radio frequency radiation for wireless and mobile connection of various devices for telecommunication and data processing.

A baby sleeping. A cordless device monitoring it.

Baby monitors

Baby monitors are electrical devices and produce low-frequency electric and magnetic fields in the 50 Hz range if they are powered by electricity from the socket. Radio-operated devices use high-frequency electromagnetic fields to transmit sounds. They use two different technologies to transfer noise from the nursery to parents and thus give them the opportunity to control their babies or toddlers from the distance: the electrical grid of the house or flat or a radio system. Today most of the baby monitors apply wireless communication.

BOS: Digital Radio of Security Authorities and Organisations

Security authorities and organisations as, for example, police forces, fire brigades and rescue services operate a radio network of their own which is strictly separated from other radio networks. At present a trunked radio system network is set up in many European countries using digital signal transmission according to the standard TETRA.

A man, a woman and a girl with suitcases on their way to the plane

Radiation protection aspects in full-body scanners

Especially at airports full-body scanners are increasingly used for security screening (passenger screening). The devices can detect and locate forbidden objects concealed under a person's clothing. In contrast to metal detectors used extensively at passenger airports, these devices also respond to non-metallic objects such as explosives.

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