Progress of Radio

Sun (Auckland), Volume II, Issue 404, 12 July 1928, Page 7 (Supplement)

Progress of Radio

astonishing development Peeps Into the Future OH, yes, I mean to get a set eventually, but not just at present,” said Jones to me -while I -was discussing with him the advances of radio during the last few years. “With all these developments a set of to-day will be obsolete by next year.” This statement sums up the chief objection of a certain class of people throughout the world. Believing themselves to be careful men with an infinite amount of forethought, they refuse to take advantage of this marvel of the age. Rather than risk owning a set which recent developments have made out of date, they deny themselves an infinity of education and amusement.

I knew .Tones 20 years ago. He was then considering buying a motor-car. ■‘Stilt, it I wait until next year,” he thought (this was in 1909), "I will be -ettins a much better car at the same Jrlce." He was still a pedestrian „hen I met him last and such, no aoubt, will he remain until a motorvehicle bears him to his last resting place! Scientific men the world over tell UB that to-day radio has reached a point from which no radical advance can be expected for the next few vears. Then the change will be analagous to that when the thermonic valve, or “vacuum toob” of the Americans, replaced crystal rectifiers and coherers. Any changes to-day must be along the lines of Increased purity of tone, of selectivity and of simplicity of control. TONE PURITY Many advances toward perfect tone have been made during the past few years. Resistance coupling and dualimpedance amplification with its somewhat critical adjustment, bid fair for a time to supersede transformer coupling, but the introduction of the C-battery and special valves for all stages, and improvements in the actual construction has brought the old method back to popularity. Its use will certainly give the largest amplification for a given number of valves and a fixed plate potential, and a push-pull stage -will give a volume too great for any loud speaker, unless specially designed, to handle without distortion. The loud speaker itself has in the past been the greatest obstacle in the path of seekers for pure tone. In the United States especially the horn type has failed to keep pace with radio advancement, but a cone speaker was evolved after much research. Both have their drawbacks, the first failing to reproduce the very low notes and the other, while reproducing the bass notes perfectly', fails on the upper treble register. Those who could afford the expense have frequently used both types together quite successfully, but slight distortion was present even then through each attempting to reproduce notes beyond its compass. Of late American manufacturers have combined the two principles in an ingenious manner in an electricdynamic cone speaker, which is recosidsed by all as outstanding in tonal qualities. The gramophone and the wireless

have always been deadly enemies, but now a compromise has been effected. Leading gramophone manufacturers are using principles learned from radio in building their products for competitive sale, and broadcasting stations are using gramophone music to supplement programmes. There is little to choose between the volume and clarity with which an electric recording is reproduced by the modern valve amplifier in a gramophone, and the same item heard “over the air” on a high-grade set. The variety of programme and sense of personal touch offered by the latter must always weigh in its favour. The modern radio .receiver now takes its place among the musical instruments. The receiver of to-day is easily controlled. The numerous dials and knobs of three years ago have been reduced by two-thirds. Self-adjusting rheostats and automatic jacks and slow-motion dials have made tuning almost as simple as -winding a gramophone or switching on the electric light. THE ULTIMATE RECEIVER Already radio is fast developing toward the time when batteries will be unknown and all power will be drawn direct from the lighting mains. Some manufacturers are building eliminators as an integral part of the higherpriced sets, dispensing in one move with A, B and C-batteries. Others supply special valves with the filament heated indirectly by current from the mains. Before long it is unlikely that anyone -with electric light in his house will dream of using batteries for his radio set any more than he would now operate his va-cuum-cleaner. Tuning will be made still easier and the mere pulling ol' a switch will bring in the required station. Aerials will be displaced by self-contained loops and the whole set will be more compact, and easily handled. But all these are merely refinements that can be added to any set as they come into common use. The basic principle is the same to-day as when Marconi first sent a message over the then incredible distance of 12 miles Valve transmission has replaced the noisy spark for code messages and has made possible modern broadcasting. Theatre proprietors and the hitherto unapproachable great artists have at last been won over, and discerning critics now see the first signs of a wave of popularity which will sweep broadcasting into an unassailable place in the life of the world and place a receiving set in every home. The modern receiving set must now take its place among the musical instruments, a truth which is being recognised in an increasing degree by the world’s leaders in music. The famous pianist, Moiseiwitsch, who has only recently finished his tour of the Dominion, is but one of the many who hail the new' entertainer as a fit vehicle for the art of even a master.