In the English literature, which has also become known in German-speaking countries, it was always assumed that the first EME was done in the USA. But according to reports by Dr. Ing. W. Stepp in the "Der Seewart" magazine, it seems that already in 1943, during experiments with radio measurement equipment, (radar) reflections of the moon were received and recognized as such. Since so far nothing was published about this in cq-DL, the report by Dr. Stepp is presented here as a preamble to the activities of German VHF amateurs.
Dr. Stepp writes: "In 1943 Telefunken had taken up the task of developing radio measuring equipment for detecting and surveying targets near ground -- ships, low-flying aircraft, cars -- with as large a range as possible.
The task of locating near-ground targets especially required, besides high power and high receiver sensitivity, wavelengths as short as possible. A setup with the following parameters was developed, matching the possibilities of that time:
|Transmitter impulse power||120 kW|
|Impulse duration||1.5 µs|
|Wavelength||53 cm, about 564 MHz|
|RX sensitivity||12 kTo|
|Antenna surface||45 m2|
|Number of dipoles||8 per row horiz., 80 per column vert.|
The antenna could be rotated around its vertical axis. It was strongly focused vertically with the first nulls 1.3° away from the horizontal main lobe.
The device was given the name "Würzmann". For testing, the system was set up in late 1943 on the Bakenberg on the south of the island of Rügen.
The measurement results confirmed the calculated ranges: ships of average size were detected up to the horizon, about 50 km, and airplanes till 1000 m high up to distances of about 100 km. But with favorable weather conditions the system detected targets in the harbour of Gdansk and the Gulf of Finland.
After the first tests I assigned Willi Thiel, one of the very competent engineers, to take care of the equipment on his own and continuously perform observations. Some weeks later I again travelled to the Rügen island for experiments near Göhren. On the last day of the experiments, just a few hours before leaving back to Berlin, I visited the Bakenberg again. The sky was very dull, the night very dark. On the way to the Bakenberg W. Thiel reported about a "strange equipment perturbation", which he had observed on the previous day at approximately the same time, but of which he had not been able to find the cause; however, it had become less after about two hours despite him not fixing it, and in the end had disappeared completely.
After activating the Würzmann, I made the following observation: the "perturbation" again appeared, had a duration of several impulses, and larger impulse strength than the strongest nearby targets. It didn't appear until about two seconds after switching on the transmitter and disappeared (pulsatingly) correspondingly later after switching it off. But the rest of the echo image appeared and disappeared at the instance of switching the transmitter on/off. The "perturbation" only occurred when the antenna was aimed to the east, and it disappeared immediately upon a major change of direction, but reappeared only about two seconds after rotating back to the original direction. Apparently we had detected the rising moon behind the clouds with the equipment. I explained the gradual disappearance of the impulses by the reflecting body slowly moving out of the strongly focussed, horizontally aimed beam, as it rises above the horizon. Soon after this, the equipment was put into regular use, and I haven't heard about further observations."