Alexanderson antenna
The Alexanderson antenna is a transmission antenna previously used for long - wave and long-wave transmitters with similar properties to the T antenna . It was invented by Ernst Alexanderson . It usually consists of earthed towers between which several overhead lines are stretched to form a roof capacity . This is followed by extension coils and vertical wires, the actual radiators. The transmission energy is fed between its base point and the earth network . The coils are tuned so that they form a resonance circuit for the transmission frequency with the wire capacitance and the tower . The advantages of an Alexanderson antenna are that the heavy masts do not require foot insulators and the mast height is relatively low.
The only Alexanderson antenna currently in continuous use is in Kalundborg , Denmark. This antenna has been broadcasting digital programs in DRM since October 2008 .
Executed systems
- Radio station Kalundborg (long wave transmitter 243 kHz)
- Longest wave transmitter Grimeton (17.2 kHz)
- Further, but no longer existing long-wave transmitters, see machine transmitters