PROGRESS IN RADIO

Hokitika Guardian, 16 July 1930, Page 8

PROGRESS IN RADIO

HISTORY REPEATING. ILKING ALONG LIGHT BEAM. One hears so much these days alou r. lie progress of radio, it is easy t; orget just what has been done al •eaciy, and what may be considered still pioneering work. The tendency efore the war was toward higher and 'MI higher waves, until such station •s Chita no in It p t ly, and several Br't -sh stations, well known to old Bands were transmitting on waves not far off 20,000 metres.. At present few eople are' interested in these Ion? • waves, and it may not be long before hitidns over 4000 jmetres become tin yr->r> J 'on rathop flian the rule. But 1 din history ha, f. gone further ipty short .waves than, .might be expected at a glance. When, radio was first discovered, it was, thanks to waves only a few millimetres in length. Quit? a lot of work was done on these waves. and indeed far-(Sorter waves. TALKING ALONG BEAMS OF RIGHT. Bell himself, the man who gave .th lephone receiver and the microphone > the world was busy transmitting telephony along light rays. Light rays are radio waves,, or if you like.it better radio waves .are only longer light waves. His system was quite a success, but it was limited to direct lines clear of all obstructions. So lie experimented with heat waves of a far longer wave-length than light, and found he could transmit speech with them through walls and fog quite easily. It was not until the early days of Sir Oliver Lodge that the advantages of still longer light waves were discovered. Nothing seemed to get in their way—not even mountain ranges. telephony experiments came to a- standstill, for: it was impossible to generate these loncror waves reliably’. They were generated in- spurts and start?, quite un••Mpcl to telephony. Nevertheless, Mio German Navy before that time had more or less perfected methods of sneaking along the beams of a search’’izht. . \ ! VALUE OF THE VALVE. , ,»j). Tt was not until the discovery of the valve and its-properties than man could , generate waves, similar to light, but of far longer wave-length m one continuous stream. Tt was then possible to transmit speech along them, and the first programme grouser was horn. T t was .soon found, however, that this new method of generating radio waves ~ its limit. -There was no limit to tlie generation of longer and longer waves, but in the other direction there was and still is a distinct limit. No •alve can generate light waves or even ’■"at waves, although very short wave f,,o nsmittors get very close to it. A valve generating visible light waves would, of course, require no radio set to ■’elect the waves. We...should see. the waves as light. The valve would have trespassed on the reserves of cand’'■•s and electric bulbs, and presumably we should bg pretty close to the long sneght- source of cold night. What good all tin’s would he. nobody at the moment nuite knows, hut all manner interesting tilings might eventuate hist bemuse radio h’story was repeatitself, only in a different way.