English: A "cage line" transmission line to feed radio power to the antenna mast (background) of the Solt transmitter (Hungarian: Solti rádióadó) for Kossuth Rádió near Solt, Hungary which broadcasts on 540 kHz in the medium wave (MW) band. With an output power of 2000 kW (2 MW) it is the most powerful medium wave radio transmitter in Europe and also the most powerful in the world (along with three Saudi transmitters). The line consists of an inner circular bundle of parallel wires carrying the power, surrounded by an outer circle of grounded wires that function as a "shield". The line functions similarly to a large coaxial cable. Cage lines are used to carry low frequency, high power RF currents.