There is something new at the Deutsches Museum in Munich! Since autumn 2018, the world-famous science and technology museum has its own medium wave transmitter: “Radio Eule” is broadcast on 1500 kHz.
In the tradition of the beginnings of radio
By the way, the transmitter with the museum mascot in its name transmits with 1500 kHz on a frequency full of history. It is exactly double the frequency of the first German radio station built in 1923 on the Vox building in Berlin. This special exhibit in the Deutsches Museum thus pays tribute to the technical invention of radio.
It is also interesting to note that the representation of the frequency in Roman numerals (MD) in reverse order corresponds to the initials of the Deutsches Museeum.
Inspiring the young generation
With its simple structure, “Radio Eule” is intended to introduce young museum visitors in particular to a technology that is still the basis for the transmission of digital data today. Under the guidance of museum educators, school classes can design their own radio program and build a medium wave receiver using cardboard, copper wire, capacitor and other materials.
Full reception, also digital!
With its 10 W ERP power, “Radio Eule” can be heard in the area around Munich’s Museum Island. “In exceptional weather conditions and with special antennas, however, reception is even possible from abroad,” explains Max Rößner. He reports about an amateur radio operator who received “Radio Eule” in Salzburg. The record for the most distant reception is currently held by a radio fan from the Italian Liguria. He received the station via WebSDR about 500 kilometers from the museum.
“Technology from the past paired with future technologies – that’s typical Deutsches Museum,” says its general director Wolfgang M. Heckl.
The antenna is a monopole (Marconi antenna) with a length of 50 meters (λ/4). The antenna consists of a dyneema rope with a diameter of 5mm with a bronze strand.
The antenna is tensioned from the mast on the museum tower diagonally downwards towards the north. The base of the antenna is at the top of the museum tower (h = approx. 66 m).
The transmitter was installed by the Rundfunkmuseum Cham, it has an automatic level control, which makes the level control much easier.
The transmitter consists of parts of the former Nautel AM transmitter which was operated on 801 kHz by the Bavarian Radio in Ismaning. The transmitter works with a rectangular PWM modulation. The harmonics are properly suppressed by a downstream filter.
Program contents are broadcast 24/7, with a professional mp3 player playing a looped program consisting of several hours of music and scientific/technical word contributions.
In 2015, the last medium- and long-wave transmitters were switched off in Germany. In the opinion of many radio enthusiasts, this also marked the end of a popular and easy introduction to the world of amateur radio.
A friend of the Deutsches Museum was especially sad to say goodbye to medium wave radio.The passionate radio amateur Christoph Heiner gave the impulse for the project “Radio Eule” and found open ears with Wolfgang M. Heckl.
During the ” Langen Nacht der Münchner Museen 2018″, “Radio Eule” went “on air” for the first time in a test run. A few months later, the temporary installation on the tower was replaced by a more powerful transmitter. Support was provided by the Radio Museum Cham.
In July 2019, the original transmitter prototype was replaced by a powerful unit transmitting at the frequency 1500 kHz (λ = 200 m) with 10 W EIRP in cooperation with the Rundfunkmuseum Cham. (Return <0.5 W modulation: approx. 50 %).
Luise Allendorf-Hoefer, Dipl.-Ing.
Curator Communications Engineering and Electronics
Deutsches Museum von Meisterwerken der Naturwissenschaft und Technik (AdöR) Museumsinsel 1