PROGRESS IN 1927

Radio Record, Volume I, Issue 39, 13 April 1928, Page 16

PROGRESS IN 1927

AN AMERICAN REVIEW _ {By Dr. Alfred N. Goldsmith, Chief Broadcast Iingineer, Radiy Corporation of Amcrica.) There are some years in the development of radio which mark the cnd of one era and the begimming of another. Among these years has been 1927, for during this year certain basic tendencies have proved their importance in radio developmcrt, have been definitely accepted by tg: enginects and the public, and may now he expected to lead to continued further developtient along proved lines. It is now recognised that the era of unregulated or only partially regulated radio transtnission has come to an end. The passage ot the Iederal Radio Act of 1927, arid the appointment of the Fede1al Radio Conimission under the provisions of the law, have for the first time enabled the Governmental regulating powers to be exercised systematically in the direction of of minimising interference between broadcasting stations and allocating frequencies to such stations based on a nationally applicable plan, and vet flexible toward local conditions. ‘The excellent preliminary work of the Department of Commerce along these lines prior to the passage of the 1927. Radio Law has heen utilised as a foundation bv the Federal Radio Commission, One great contribution of the commission has heen its consistent unwillineness to permit the erection and operation of unnecessary additional broadcasting stations i regions already adennately served. The circumstances just mentioned have had a considerable influence on radio receiver design. Since it has become evident that an indefinite multiplication of stations will not be permitted, and that the congestion of stations in a given district will be greatly reduced and the field strengths corresponding to the various programme signals will be systematically increased, the designers of receiving sets have been enabled to produce generally useful but simple and compact receiyers with greater assurance than heretofore, It is now reasonably certain that stations of considerable power having frequency allocations less than 60 ke, apart will not be erected within a given district; that the building of powerful stations in regions of high population density will be discouraged; and that stations giving a demonstrably valuable service to the public will be

afforded channels for clear reception up to the reasonable range of the station, Concurrent with the use of transmitters having a power of several tens of kilowatts las been the inevitable improvement of radio reception in 1millions of homes. Signal field strengths capable of riding above local man made and atmospheric electrical disturbances haye become so common in the more fortunate districts that the lis. / teners have heen definitely educated to regard such powerful and clear signals as normal. At the same time, the average listener naturally, is dissatisfied with the fechle and mangled signal from distant stations, and, as a result, only those listeners who are compelled by their location to listen exelusively to distant stations coustitute"’ any considerable percentage of "Jong-distance searchers."" ‘This change in listener psychology, coresponding to a demand for loud and clear signals, and a refusal to listen to weak or mutilated signals, together with a considerable loss of interest in distant reception, has brought to the fore the matter of quality or fidelity of tone reproduction. The influence of this demand by the listeners has led to the widespread use of higher quality londspeakers, capable of giving considerable sound intensities, and fed from so-called "power valves" in the. last audio-frequency stage of the receiving set. Where a few hundredths of a watt was at one time regarded as adeauate for the final practically undistorted audio-frequency output of a receiver, to-day a power in excess of a watt is becoming common. As a result of this evolution in the acoustic system of receiving sets, listeners are now enahled to secure a reasonably faithful and natural reproduction of the original performance, and an increasingly critical musical faculty is being developed among listeners. Persons who, several years ago, hardly knew one note from another, are to-dar enjoying well-renroduced symphony concerts, and are developing a real under. standing of the higher types of musical entertainment. *

The listeners are, concentrating their attention on local stations, which give high-quality programmes, and produce loud and clear signals in their vicinity, atid this audience demands receiving sets haying excellent tonal quality of reproduction, with adequate volume of sound, As is but natural, such listencrs also insist upon simplicty of operation. We have, therefore, also come to the end of the era of radio receivers, which are too complicated to operate. ‘To-day, the single selector (unicontrol) type of receiving set is practically standard. A minimum of receiver adjustments is regarded with fayow by the listeners, and, even more marked, is the tendency to:

ward stocket power operation of receiving sets, The replacement or charging of batteries is on the decline, Simple and reliable receivers, utilising lighting cirenit powers exclusively for their operation, have now become widely available, and the public response to them has heen so enthusiastic that there can be no question that the socket-power-operated receiver is the type to he most , generally used during the next radio. era, A number of receiving sets have been nade available during 1927, which clearIv belong to the new era in radio reception.