CHILDREN RING UP

Hokitika Guardian, 17 February 1932, Page 6

CHILDREN RING UP

NEW ZEALAND FROM A CALL-BOX

HOW SCIENCE HAS SHRUNK THE EMPIRE.

TELEPHONE MARVELS AT LONDON

EXHIBITION

(From a Correspondent.)

LONDON, January 6th

A small hoy walked into a red tele-, phone kiosk at tile imperial Institute, .London, and said “Hello, New Zealand” into the receiver. New Zealand answered. That is one of the thrilG that is attracting thousands of children, of all ages from nve up to ao. and over, to the Young People’s Telephone Exhibition, opened yesterday bv the Postmaster-General m order to make the rising generation ••tele-phone-minded,” But the display also shows them one of the greatest of model'll miracles —how science has shrunk the Empiio Once inside the telephone box, Auckland is no further off than South Kensington Underground Station. At intervals, a spotlight is turned on to the smiling crowd of children. The youngster on whom it falls is picked out and kd into the kiosk to telephone to some distant country or maybe to a ship at sea. ' Concealed amplifiers broadcast both sides of the conversation to the excited crowd of fel-low-clnidreit outside. This stunt is the star turn of London childrens Christmas holidays.

“Speed In Speech.”

Tim British Post Office has laid itself out to explain, in tins exhibition, “How it’s done.” The display tells the story of “speech in speech ol how man has conquered distance in communication‘with ids fellows, lhe small boy who talks to Australia, or any other overseas country, has only got to cross the hall to see a model ot Rugby, the most powerful wireless station in the world, where his faltering voice was turned into waves which travelled 12,000 miles across the world.

This small boy is also given a glimpse of what happens to Lis telephone call at the Exchange. He can watch it flicking through the complex mechanism of an automatic exchange without any human help. At present, overseas calls go*through the ordinary exchanges but a special overseas switchboard .is’nearing completion at the General Post Office which will handle all these calls, and which is, it is officially stated, tile most up-to-date efficient in the world.

Next door there is a working model of an ultra short-wave wireless telephony set, still in the experimental stage. It works on a wavelength of 2 to 5 metres. Words . spoken into an ordinary telephone at one end'of the •stand come''out through a loud-speak-er at the other end—having been transmitted on a two or three metie wavelength. 1,000 Miles in One Yard.

Tn another part of tile hall you can talk , into a telephone to *> listener one yard away— and your voice travels 1.000 miles between the two instruments. The line goes up to Glasgow and hack. iPost Office engineers have devoted a stand to telling you how this is made possible. A model illustrates graphically how a speech impulse travels m waves, like a ripple on the water, 'these get fainter and fainter as the voice continues on its journey. They would fade out altogether were it not for loading coils, which are put in at intervals to re-energise the impulse. There are seven “repeaters.” re-energising stations, between 'London and Edinburgh, for instance, and 27 between London and Merlin.

Some people have good telephonevoices and some had. It all depends on the number n!' “harmonics” in a voice. If yon have a lot, the reception is had because harmonics cannot. he transmitted over ordinary telephone lines. ,\ voice with the harmonics cut out loses all its character and tone. This is one of the big problems of establishing relay stations for broadcasting. A relay line Imilt for the British Broadcasting Corporation, for instance, cost, £5(10.000 because of the elaborate devices for transmitting every range and gradation of sound-including even the shrill note of the piccolo.

What Shape Is Your Voice? What is the shape of your voice t Is n angular or curved:' jagged or jump,' . Visitors are able to see their own voices at the Exhibition. The voice appears as a wriggling, jumping beam of blue light. Mach voice looks difleient. A shrill note makes the beam shimmy feverishly. A deep hark results in big, sudden jumps. I his client is obtained by speaking into an ordinary receiver attached to a cathode rav oscillograph. The beam ol blue light is thrown on the end of the valve airt is deflected by the impulse of the voice. This beam dames about, forming dil--1 fefent shapes according to the strength am| I requenrv of t In' voice. The latest invention in telegraphy is at t ract ing crowds ol eager children. This is the teleprinter. This instrument looks like an ordinary typewriter with a standard keyboard. The operator simply types the message an it is simultaneously reproduced, at. the rate of' Mfif) characters a minute, on a distant typewriter at. say. Glasgow, or Plymouth. It appears without human intervention, as a typewritten strip which is pasted on to the telegraph form Teleprinters were originally invented bv a Glasgow Post Office mechanic called Greed. .Now they are rapidly superseding all other instruments used fot sending telegrams.