FM transmitter (personal device)

Mini transmitter ( also called transmitters ) disseminate any audio signal in the immediate vicinity on an FM frequency. Thus, for example, the music as an MP3 player can be played on any radio without a cable connection to the radio is necessary. This is advantageous, for example if a car radio has no external audio inputs.

Such mini-transmitter found in recent years, first outside Germany, including in the U.S., proliferation. There, the operation is also allowed. In Germany, the transmitters were en masse offered since around 2003 in Internet auctions, although their operation was initially banned. Since the beginning of 2006, the Federal Network Agency allows the operation of devices with a CE marking and an effective transmission power of 50 watts ERP Nano. In other German-speaking countries such as Switzerland, the use is also permitted; in Austria the sale and use is allowed since December 2006. With this performance, just a few meters can be bridged. However, devices are available, the transmit power moves into the range of a few milliwatts. These are outdoor up to about 200 meters with an ordinary radio audibly and can interfere with other radios in the vicinity if an already occupied frequency is selected. There are users who solder a piece of wire as an antenna at the transmitting transistor and thus increase the range of.

The mini transmitter usually cost between 10 and 50 euros and are partly stereo compatible. Some may choose any frequency the entire range from 88 to 108 MHz with PLL technology. Others offer just their fixed frequencies. Among the non-approved devices are also those that can send below the FM threshold of 87.5 MHz. These devices use frequencies in the 4- meter band, which are used in Germany, among others, for the non-public bad radio.

For the operation of such a mini transmitter frequency is needed on the no radio program is broadcast.

The Nokia N8 and Nokia 808 Pure View are smartphones with built-in FM transmitter, with the music, but also, for example, the navigation message can be transmitted to the car radio.

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  • Available 7/2006 the Federal Network Agency (PDF file, 19 kiB )
  • Heise News: Federal Network Agency permits private radio with 50 NW
  • Broadcasting Technology
  • Radio transmitter
Audiosignal Very high frequency Effective radiated power
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