Alexanderson Day
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The Alexanderson Day, named after the inventor Ernst Fredrik Werner Alexanderson, is the day of the open house (first Sunday of July each year) at the VLF transmitter Grimeton. On Alexanderson Day the only workable Alexanderson alternator transmitter in the world is used to transmit short Morse messages on 17.2 kHz, which should be easily receivable in all of Europe. A modern and very convenient way for their reception is a PC with a coil connected to the soundcard input and FFT analysis software. The transmitter is preserved as a historical remnant of early radio technology and as an example of VLF (Very Low Frequency) equipment.
