The antenna feeder is mainly used in concern cars (VW, Škoda, Audi, Seat) from 1998 to the present. The original car radios have special phantom power for the antenna built inside, but the new aftermarket car radios do not have this in them. Therefore, if we want the amplifier in the antenna to work, we need to purchase a power supply , which will solve the problem with powering the car antenna. This is a so-called phantom power supply, i.e. via coax. There are several types of antenna feeders, but the most basic ones are ISO-DIN and FAKRA-DIN . The antenna power supply is connected between the new car radio and the antenna connector in the car. The antenna feeder always has a blue switching cable that connects to the switched plus on the opposite side of the ISO connector, usually position No. 5, a blue or blue-white cable.