This standard describes the methods of measuring the magnetic characteristics of cylindrical, tubular and threaded cores, depending on the inductance L and the quality factor Q of a certain coil containing said core, also specifying the position of the core. with respect to the coil. For testing purposes, cores are normally controlled by comparative measurements with respect to a standard core. This standard covers cores up to 45 mm in length and 8.5 mm in diameter, for frequencies lower than 100 MHz. The dimensional characteristics of such cores are contained in standards UNE 20-583 parts 1 and 3. The determination of The magnetic properties of ferrite antenna bars constitute the subject of the UNE 20-586 standard.