Abstract
IN the General Electric Co.'s (G.E.C.) Journal of May and August a description is given by D. C. Espley and G. W. Edwards of television receivers made by the G.E.C. and how they have withstood the tests to which they have been subjected. Since the Commission, formed in May 1934, considered the position of television as a public service, it has come very much to the front. The Commission decided that the standard picture should not be less than 240 lines, with 25 frames per second as the repetition frequency. They further recommended that work should be started on an experimental transmitting station with a 450 line 50 frame per second. The G.E.C. Research Laboratories concentrated, therefore, on the forthcoming transmissions from the Alexandra Palace. It was originally expected that this transmitter would provide good signals within a circular area of 25 miles radius. Results with the receivers have exceeded expectations. At Reading (39 miles), Tunbridge Wells (38 miles), Maidstone (38 miles), Farnham (42 miles) and Brighton (56 miles) the results are entirely satisfactory. Using a modified set, it was found possible to obtain a well-synchronized picture at the G.E.C. Radio Works at Coventry (80 miles), although at this distance the appreciable 'background' noise must produce visible effects on the picture. Apart from the effects of local irregularities, it is now stated that the field strength round the transmitter has an almost circular distribution. The small irregularities are generally due to shadows produced by the proximity of buildings and the contour of the hills. In a few cases it was found necessary to erect aerials with directional properties either for raising low field strength or to avoid local interference when it is excessive.
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Television Receivers. Nature 141, 113 (1938). https://doi.org/10.1038/141113a0
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DOI: https://doi.org/10.1038/141113a0