Ultra-short Waves

Radio Record, Volume IV, Issue 25, 2 January 1931, Page 11

Ultra-short Waves

Aid to Navigation WAVES as low as 8 metres are conducted by the Heaviside layer, and can be received at places thousands of miles away, but all long-distance reception abruptly ceases below 8 metres. It is also found that the wireless waves no longer come back from space, but spread in a similar way to those of light. A German experimenter, Werner Ludenio, hag set himself the task of investigating extremely short. waves of less than a metre in length, and experimenting in their transmission to distances of 10 kilometres and more. A transmitter of very high radiating power, and a highly sensitive receiver, were specially designed for the experiment. Reflectors of dimensions depending upon the wavelength were used both at the transmitting and receiving ends. Radiation through space alone seems to be responsible for the spreading of these very short waves. ‘Trees, houses, and hills, located on a straight line between the transmitter and receiver, are perfect absorbents. No atmospheric disturbance due to thunderstorms or fading has been noted, but the beams were found to be absorbed in bright sunlight to some extent, particularly above water or snow. Dense fog, rain, and snowstorms are traversed by the beams without any reduction in intensity. Inasmuch ag atmospheric influences have uno effect upon these waves, they are admirably suited for navigation purposes, both in mid-air and on the ocean. They would enable a ’plane or ship safely to steer its course through even the densest fog. Both marine and aerial navigation will thus be able to fight the worst foe of safety, eliminating the most frequent cause of accidents.