Abstract
THE annual exhibition of wireless apparatus organized by the Radio Manufacturers' Association was held at Olympia on August 24 until September 3, and it was notable for such features as the replacement of the B.B.C. Radio Theatre by a glass-walled television studio in operation, the first large display of television receivers in actual operation on exhibitors' stands, and the complete demonstration of sound broadcasting receivers for the first time. On previous occasions the stands were supplied inside the exhibition with audio-frequency programme current, so that no demonstration of the radio frequency portion of receivers could be given. This year, arrangements were made for all stands to be supplied with radio frequency signals so that the various receivers could be demonstrated as a whole. On the technical side, sound broadcasting receivers appear to have settled down to fairly standard types of design, and with the steady improvement of detail which has resulted in methods of lay-out and manufacture during recent years, the modern receiver is very efficient and supplies the needs of the majority of listeners. The chief novel feature among this year's sets is the incorporation of some form of automatic tuning, by means of which a certain number of broadcasting stations can be selected at will by operating switches on the front of the receiver. To what extent this feature was really required by the listener time will tell, but it would appear to be consistent with the demands of the age and to have advantages comparable with those of the automatic telephone and the pre-selector gear on motor-cars. The automatically tuned receiver is provided with a series of about six push-buttons in addition to the usual on-and-off switch; by pressing one of these buttons, the receiver is automatically adjusted to receive the programme from a certain station. In some cases the actual stations made available to the press-button control can be altered by carrying out certain more or less simple adjustments on the receiver. The manner of achieving this automatic tuning varies among the manufacturers and has called forth a considerable amount of mechanical ingenuity in some cases. The methods vary from the switching in of one of a series of fixed condensers across each tuned circuit of the receiver, to the use of a motor driving the main ganged variable condenser in conjunction with an electrical method of obtaining accurate synchronism with the incoming signals. In all cases, the purchaser is assured that the addition of this automatic device in no way reduces the efficiency of the receiver as a whole or affects the ability to operate it manually.
Article PDF
Rights and permissions
About this article
Cite this article
S.-R., R. Radio Exhibition, Olympia. Nature 142, 445–446 (1938). https://doi.org/10.1038/142445a0
Issue Date:
DOI: https://doi.org/10.1038/142445a0