"MICRO-RAY"

Evening Post, Volume CXI, Issue 78, 2 April 1931, Page 10

"MICRO-RAY"

ULTRA-SHORT V^WES

EXTRAORDINARY CLAIMS

United Tress Association —By Electric Telegraph—Copyright. LONDON, 31st March. Secret wireless telephony at un amazingly cheap rate is promised by the French inventors of a new, ultrji-short-wave system which was demonstrated by Post Office officials who conversed from the Cliffs of Dover with IFrench engineers at Calais with a waveilcngth. of 18 centimetres. The transmitting and receiving aerials are less than an inch long, and the amazingly low power of Tialf a ■watt, which is barely sufficient to light a flash^ght bulb, is used. The discovery is known as "inicroray," arid its essential principle is a guarded secret. Briefly, speakers' voices are converted into a ray which is concentrated by two reflectors into a fine pencil ray, which behaves in a, manner similar to that of light. It is thrown into- space and picked up hy an associated apparatus at the other .end. The success of the experiments envisages the complete disappearance of expensive, tall aerials and elaborate stations, and the end of the present serious congestion of the ether. Also, it presages universal radio telephony at a relatively small cost, and the intense development of television, which is brought '.within comimorcial grounds. The "Morning Post" says the presence of numerous foreign high officials reveals' the interest aroused.

The French invention referred to is based on the work of M. Pierret and M. Beauvais. Such excessively' short waves demand the adoption of quite unorthodox ways of using radio apparatus, though the generator is the usual type of valve. The statement, that its essential principle is "a,closely guarded secret" is an exaggeration. Pierret's circuit has been described in popular wireless journals in England and no suggestion of secrecy was made. The forecasts mentioned in the latter part of the message are also much exaggerated. The scope for the use of ultra-short waves which travel in straight lines as light does is severely limited by that fact alone. The range of operation is practically limited to distances between points in sight of one another. Beauvais, a few months ago established communication over a distance of six miles with waves of 17 centimetres. Pierret produced waves as short as 12 centimetres (about Si inches). '