English:
Antenna towers for the long wave (
VLF
) radio transmitter site at Grimeton, Sweden. The
Grimeton station
, built 1922-1924, has the only working
Alexanderson alternator
rotating armature radio transmitter, and has been made a World Heritage site. It transmits at 17.2 kHz (wavelength 17.4 kilometers) with callsign SAQ. The
flattop antenna
consists of eight vertical feeder wires from the transmitter which feed energy to eight horizontal 1900 meter (1.2 mile) parallel topload wires, supported on 46 m crossarms on six 127 m towers, shown here. The vertical wires are the radiating elements, while the horizontal wires serve as a capacitor plate which increases the current in the vertical wires, increasing the output power. There is a buried network of
ground
wires under the antenna which serves as the other plate of the "capacitor". Information from
Radiostation Grimeton, The Alexanderson Society