GREAT DISPLAY

Poverty Bay Herald, Volume LV, Issue 17237, 17 April 1930, Page 11

GREAT DISPLAY

RADIO EXHIBITION THE ALL-ELECTRIC SET Splendid exhibits of receivers and radio apparatus were revealed when the Klectricaj and Radio Exhibitiuu opened a few days ago at tlie Town Hall, Sydney. .Wore than IC9O sets from the crystal to tlio nine valve console, were shown There were sets intended for local stations, set* that will "get the world," sets of every type and design, forming an array such as Sydney had never before seen.

Tim wireless enthusiast noticed that electricity is being called into use in many more and astonishing ways every year', but for him. the real part of the exhibition, that dealing with radio, left the impression of substantial progress Not that the radio section holds anything remarkably spectacular, unless it is the Fultograph. which receives pictures by wireless and pruts them in in,lit ~'f you. or the delicate relays which enable Marconi, from "somewhere in the Mediterranean," to switch on lights in the Sydney Town Hall. These arc the indications of radio's most definite advances along certain lines since last year. But in the array of receivers, speakers, and all the adjuncts of the modern set. the visitor will probably find more to interest him than in these scientific features.

The preponderance of ihe nil rlcelrie set was noted 12 months ago, at the last exhibition. Then, a*' course, the electric receiver was in little more than an experimental stage; its tremendous advantages were realised, but there were still many difficulties to overcome. .Manufacturers have learnt much since then, and at the exhibition the nearperfection of the "mains-driven" receiver will be ;i matter of interest to the most casual visitor.

An interesting commentary on this Aspect is the fact that there are over 35 different makes of electric receivers on display against only 20 of the bat-tery-operated type. SCREEN* r.KIT) VALVES

The newer and more technical development of the screen-grid valve is also well represented There are 24 different makes of this type of set, whose .advantages, of course, cannot be appreciated until the receivers are taken home and put to the test

And then, a step further, is the radiogramophone combination, for the most part elaborate pieces of furniture of the class wherein expense is no object. The cabinet work here is particularly fine, for "radio-pl.ono" combinations arc mas* sive items,' taking in two separate units —the receiver md gramophone—and allow the cabinetmaker full scope.

AUSTRALIAN-MADE

The percentage of Australian-made gear is fairly high, but evidently not so high as it should he when the new tariff has lad time to operate fully.

A rough estimate would place the pro portion of locally-made receivers at a tittle under half the total number being exhibited. Amongst, some of the accessories and parts it is probably higher, although the keen observer will note that there are some, lines which the Australian manufacturer has scarcely touched—valves and speakers, for example. One thing is made quite evident at the exhibition—the battery set, has been relegated to the position of Cinderella in the radio family. Technical progress, it has been remarked more than once, follows a lead more or less' blindly, often to the neglect of other paths." Radio engineers, it is quite evident, have used all their energies in perfecting the mains-driven receiver: the battery operated job is in much the same place as ia was last year. To this, ,of course, the screen grid roceiver oilers'the outstanding exception.

I Looking over the exhibition sets, every one of them a highly-finished and scion- [ tine piece of mechanism, one might be inclined to ask: "What more can the I engineers bo expected to do?" The (acme in simplicity was readied some two years ago Selectivity and the avoidance of any form of interference are matters more of gradual evolution than progressive jumps, and further improvement, in this ; respect will probably come Prom out'side sources, rather than from the receivers themselves Tone and "faith.fulness of reproduction" appear to have } reached a point which not only equals the original, but betters it. i With tone-controls and other devices for altering the actual quality of the reproduction, or cutting of the high or low frequencies—thus obtaining at will a high-pitched or bassy effecU-yott can almost make your own music. At least, in certain,amount of noise at the other end seems to be all that is required. THE POWER PACK Power packs, eliminators and amplifiers are well represented. The gramophone amplifier is becoming quite a distinct unit, in common with the larger type used for public address work and musical reproduction for balls. They follow the conventional lines, and it is noteworthy that all, with one or two exceptions, use lhe method of transformer cou]>!ing. In practically all the amplifiers the push-pull system, is employed.. Tfhc power park—almost an unknown article "last year'—has developed into nn imposing unit. :\nd speakers, one notes, are all cones, about half ol them being .dynamics.