New Stunts with Short Waves
April 1935 Short Wave Craft

April 1935 Short Wave Craft [Table of Contents] Wax nostalgic about and learn from the history of early electronics. See articles from Short Wave Craft, published 1930 - 1936. All copyrights hereby acknowledged.

As with many relatively new technologies, the exuberance over radio peaked quickly once the benefits of communications over long distances without the need for wires was realized by the public. After a couple decades a lot of "authorities" began pontificating about how all the useful applications of radio waves had been discovered and that any new innovation would be merely incremental improvements in existing technology. Novel circuits for minimizing static over the radio or maybe building more powerful transmitters for longer range were the only concepts within reach of their limited imaginations. Similar phenomena occurred for those who thought airplanes would always have two (or more) wings and that automobiles would never be faster than a train. This 1935 issue of Short Wave Craft magazine reported on the beginnings of investigations into the use of radio waves for heating and treating food and other substances in a manner that did not create a "crust" on the outside from a necessarily conductive process. Radio waves agitate matter at the molecular level throughout the entire mass, so heat is generated directly, with the added benefit of conduction aiding the heating (cooking) process. Ten years after this article appeared, Raytheon began selling its commercial Radarange microwave oven, and then in 1972 Litton introduced microwave ovens for domestic sale. My mother got her first microwave oven for Christmas of 1979, which by that time my older sister, Gayle, was living in a dormitory at the University of Maryland, and I was in the U.S. Air Force. That left her, my father, and three younger sisters (Bonnie & Brenda [twins], and Tina) in the house. She sure could have used the oven a few years earlier when there were seven hungry souls to feed.

New Stunts With Short Waves

By Dr. P. Hatschek, Berlin

Among the newest accomplishments of short waves we have "crustless" cooking - the production of artificial fever for the treatment of various human ailments - the preservation of "fresh" vegetables and fruit-making toast by short waves, et cetera.

For several years now we have heard unfounded prophecies that the evolution of the radio industry had about reached a definite development, or at least so near to the point of near-perfection that we would have to become resigned to a substantially diminished market, particularly in the case of radio receiving sets. Recent developments actually point in the opposite direction. The late German radio shows have shown such notable improvements and have brought so many new ideas into the radio industry, that there has been a tendency to exchange old sets for newer and more up-to-date equipment. This is particularly true now with the development of inexpensive single-circuit receivers with fixed selection and dynamic speakers, superheterodynes with only three tubes, marked acoustical improvements and last - but by no means least - the new short-wave receivers. Although a wide variety of possibilities have opened before the industry, it is perhaps not premature to ask whether the industry will not definitely concentrate upon the exploitation of only a few of these new developments. We are, at present, merely indicating the possibilities of these new fields, so that as soon as the apparatus has emerged from the laboratory stage, manufacturers will be able to place it in production forthwith.

"Crust-less" Baking Tomorrow by Short Waves

One of the most interesting and promising new fields before the radio industry is that of short-wave generation for special purposes, particularly at the present time in the ultra-short-wave range of 3 to 15 meters. If waves of this range pass through a circuit containing a condenser of appreciable capacity and with a considerable distance between the plates, a variety of remarkable phenomena occur with regard to objects (condenser dielectrics) introduced between the plates. Professor Esau has conducted an interesting experiment in which he placed a paraffin-water emulsion between the plates. The effect of the short waves boiled the water out of the emulsion although its temperature was only 50° to 80° Centigrade; in other words, 20° to 50° below the boiling point of water.

Therapeutic (medical) applications of this phenomenon are conceivable; for instance, replacing the emulsion by some infected portion of a human organism. Certain pathogenic constituents of the blood could thus be eliminated, while the body temperature would experience no dangerous increase. This is the principle upon which the modern "fever-machines" are based. It is already possible to apply this short-wave apparatus properly specific as to their bactericidal effect by regulating the wavelengths.

Bacteria are also responsible for the spoiling of "fresh" foods; since modern hygienic science disapproves of the sterilization of foods by boiling, etc., because of the destruction of important vitamins, it seems that the way is being opened to the utilization of short waves in this case also. The almost indefinite preservation of foods without the elimination of their vitamin content could thus be effected by simply exposing the foods to the correct type (frequency) of short-wave radiation. Somewhere in Holland a Robert Pape is working on this problem at present. In one of his laboratories there are a number of "fresh" vegetables, such as cauliflower, tomatoes and lettuce, on a table in open air, which have remained there since 1930 without losing any of their freshness; they have constantly been exposed to short-wave radiation.

As can readily be seen, the step from a laboratory apparatus to a "household implement" is not such a great one to take. Moreover, such an apparatus would be superior to our present refrigerators and certainly could hardly be more expensive to operate. Furthermore, there is the possibility of treating truly immense quantities of foods, quantities impossible to treat by present methods. Gigantic warehouses or water reservoirs could easily be kept in condition by using opposite walls as condenser plates. As yet these special generators are manufactured only for therapeutic purposes, especially those made by F. Reiner & Co., in Vienna and Dr. Paul Groag and Victor Tomberg, illustrated in Fig. 1. As is apparent from the diagram given, the idea of the hook-up lies in the three oscillating circuits, of which the middle one, No.2, is not so much a circuit as it is a "bridge." The first circuit is the usual regenerating-oscillating circuit, and the happy idea of the variable bridge (2) will make it possible to have the therapeutic circuit at practically any distance from the primary. In the therapeutic circuit (3) either two condenser plates can be used as in 3A or one plate, with the ground functioning at the second as in 3B. The body, or portion of the body to be treated, would then be placed between the two plates or between the plate and the ground respectively. The latter arrangement changes the structure of the field, as indicated in the diagram, and it would be more efficient for treating superficial areas of infection, whereas arrangement 3A would seem to be indicated for the irradiation of the subsurface. It is to be expected that in the near future small therapeutic sets of this kind will replace the present rather cumbersome arrangements and displace our high-frequency apparatus of today.

"Crustless" Baking Tomorrow by S-W's

Besides this field of utility in hygiene, there is also the possibility of using this principle in the arts of cooking and baking. Very even and penetrating heat will be achieved. As yet baking by any other means necessarily produces a crust; that is, the surface of the baked object is chemically different from the inside! With ultra short waves, on the other hand, it would be possible to achieve "crustless" baking! According to reports in the daily newspapers, a toaster for household use based on this principle has already been invented. It is by no means impossible that suitable arrangements of tubes and hook-ups will improve the efficiency of such cooking and baking utensils to the point where they will be far superior to our present electrical apparatus, based on the principle of ohmic resistance.

As can be seen from the foregoing, even the few possibilities in short-wave radio described in this article are not so far in the future as might be generally supposed. Indeed the laboratory work in some fields has progressed so far, that many types of apparatus have been manufactured as experimental specimens, and we may, in the not-far-distant future, expect the commercial appearance of a number of such devices. These speculations as to the enlargement of present radio technique and the opening up of new markets for the industry seem, therefore, not altogether out of place.