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International Television Foreseen

THE EMPIRE SERVICE

In response to enquiries as to whether there is any likelihood of an Empire Television Service being provided, the BBC states there are no plans for a television service to the Empire. Since such enquiries probably result from the inherent necessity of transmitting high-definition television on short wavelengths, the BBC thinks it may clarify the position to point out that the transmission of high-definition television necessitates the use of a very wide frequency band (more than ten times that required for sound broadcasting), which it is only practicable to obtain on wavelengths below ten metres – much shorter than used for the Empire Service. The wavebands in which the Empire Service channels are allotted are already fully occupied with transmitters separated from each other by about 10 kc/s.

An ‘ultra-short’ wavelength of about seven metres will be used for the proposed experimental high-definition television service to London. As envisaged in the ‘Report of the Television Committee’, which was presented to Parliament by the Postmaster-General in January, this service will be in the nature of a public experiment and the radius covered is not expected to be more than about twenty-five mile.

World-Radio, 20th September 1935.


TRANSATLANTIC TELEVISION

A statement recently made by Marchese Marconi that television will soon span the Atlantic has aroused considerable international interest among radio engineers. Actual television signals from Germany have been picked up in New York.

"We have maintained communication across the Atlantic on short wavelengths,'' said a GEC research engineer, "and are exploring the possibility of ultra-short-wave transmission for long-distance broadcast for television. We know that a broadcast on 15 metres can get across the Atlantic, but the objection to using this band for television is largely one of cost. Television takes up too much space in the ether. If television were broadcast from the country to America, the space would have to be obtained at the expense of normal wireless telephony communications. Telephony bands are only 10,000 cycles per second apart, whereas television bands are one million cycles per second apart and as much as three million cycles for very high definition.

"The growing use of wireless telephony makes it practically impossible for enough space on the wavelengths now in use to be sacrificed except perhaps for 90-line television requiring 100,000 cycles per second which might give a just satisfactory close-up of one person. From the beginning of television, therefore, we have been experimenting on short-wavelengths, and it is quite possible we may be able to broadcast internationally pictures of a full 400-line definition in the future."

Practical Wireless, 19th December 1936


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