CAN NOISE BE TOLERATED IN RECEPTION?

Radio Record, Volume IV, Issue 16, 31 October 1930, Page 6

CAN NOISE BE TOLERATED IN RECEPTION?

AS radio enters more deeply into the home life and becomes less of an amusement for the enthusiast, there is a demand for the freedom of the air from extraneous noises, And rightly, too, for there is no room for noise in the ether when broadcasting is to be corisidered. Interference in all its forms must ultimately be overcome, whether it be by the use of noise-preventing devices on the . part of those controlling the interfering apparatus, overcoming it by a powerful signal as in the case with the local station, or regulating the transmission hours, as in the case of Morse stations. Of the sources of interference static, electrical inteference, Morse transmission and howling valves predominate. Of these, three can, and must ultimately, be overcome if the radio set is:to take its place with the vacuum cleaner and the electric iron as a necessity of the modern household. For static there is little or no means of prevention and though there is hope that ultimately a solution to the problem will be discovered, the immediate future does not hold many prospects of improvement. Electrical interference must eventually be overcome and even prebroadcasting apparatus has been silenced to a remarkable degree. For this the Power Boards and the Post and Telegraph Department are to be congratulated, for their task in locating and curing these leakages is not an easy one. But much has yet to be done and an ether, free of electrical interference, can be hoped for only when huge sums have been spent on replacing noisy apparatus. In the majority of districts, new apparatus designed to lessen the high frequency leakage is being installed. For Morse transmission there is no excuse. It should, and must, not be allowed to interfere with

the stations broadcasting entertainment. In this respect the centres are at a distinct disadvantage and not infrequently listening is impossible. We recognise that there are certain messages that Government and other bodies must occasionally transmit, though there is no doubt that the vast majority of the messages could be held over to a more appropriate time. There is no doubt that visiting battleships frequently molest the atmosphere and in ports their presence is always made known by the marked increase in the Morse transmission. Recognising this, the Wellington Amateur Radio Society has done good work that is deserving of the commendation of all listeners within the Wellington district. | For some considerable time this society has been agitating for regulation of the ship traffic but though numerous letters are reported to have found their way to the Post and Telegraph Department nothing has apparently been done, for the interference continues. Eventually the society approached the Secretary of the Navy Department and an assurance has been given that steps are being taken to remedy the position. The text of this correspondence appears elsewhere. . 7 The howling valve is, however, evér with us, and there little hope for freedom from this nuisance until legislation prevents the use of regeneration-using sets. In many ways the constructor, for it is he who is the offender, is sealing his fate and literally asking for trouble. Broadcast listeners will not always tolerate the overenthusiastic member of their fraternity who is hopeful of getting the calls of stations outside the range of his set. There are two solutions: the use of screen grid or several stages of tuned trode r.f, stages, and the education of the user of the regeneration-using set. The wide use of the commercial s.g. set can be brought about only by the introduction of cheaper receivers and the introduction of satisfactory battery sets, for it is no secret that the battery users. are being shamefully treated in this all-electric age. Regeneration was all right when multi r.f. valve systems led to instability, but with the introduction of the screen grid all the sensitivity desired can be brought about without the use of regeneration. It is a recognised fact that with one or two valves the only reception at all satisfactory is that of the local station, but many enthusiasts become over-anxious to tune into other stations, even though these are beyond their capabilities. Their enthusiasm ruins the programmes of others who wish to listen for pleasure as against novelty. The position of the regeneration-using set owner is indeed precarious unless He mends his ways. . Thus, when all aspects are critically surveyed, it is not at all discouraging, for it seems that before broadcasting is very much older the noise level must be substantially reduced.