Automatic tuners of different brands such as ldg, mfj and cg antenna.
An antenna tuner (ATU) is a device that adapts the impecency of an antenna and that of the output of a transmitter or input of a receiver at a certain frequency.
A modern antenna tuner for amateur radios.
Normally the IN/OUT impeance of commercial transceivers is 50 ohm. The tuner would therefore be useless if the resonance frequency of the antenna was the exact one working of the equipment respecting the impecency of 50 ohm. But this is a purely theoretical situation because the environmental situation and the type of installation must also be taken into account. Therefore, there are no unique models, but only reference models that from time to time need to be adapted to the need.