On the left a lighting choke for the mast obstruction is shown. This coil with three layers for three mains' phases is parallel to the base insulator.
The three phases of a mains' cable for the obstruction light are winded up with many windings (choke) in order to obtain a very high ohmic reactance which nearly does not influence the antenna impedance.
The corona ring protects the windings below. The main's cable lies in the pipe.
The current of the mains can be brought onto the mast across the base insulator by this measure in order to supply the lamps of the obstruction light.
The cover by glass is provided for protection against touching.