RADIO REVOLUTION.

Dunstan Times, Issue 3355, 3 January 1927, Page 7

RADIO REVOLUTION.

The London Daily Telegraph’s wireless correspondent writes: Broadcasting by means or existing electrical conductors such as electric warns and telepniiiie lines, capable of reception by a '.neap, simple apparatus plugged into a House-lighting circuit or attached to a telephone, is a scheme proposed by Mr oohu v. Clusholm, ot {Secret Wireless Ltd. Air Chisholm claims to be the inventor of an apparatus which will mean the elimination ot leceivmg sets, and the substitution ol tins attachment between tho electrical conductor and tne loud-speaker or head phones. a party of Press representatives were nivited to Bireiuugton, where becret wireless Ltd. has a transmitting station lor tho purpose oi testing the invention in actual practice, and an elaborate demonstration was earned uiu. The electric lighting system oi tiie transmitting station and a few surrounding bungaiows was employed, winch, Mr Chisholm staled, was an exact small-scale lacsimue oi an ordinary town lighting system. Prom one room oi tlie transmitting station an improvised programme was transmitted, consisting oi gramophone records anu speech. About mieen loud-speakers in anrerent parts ot tlie building were connected to the Jignting circuit at various points, the special device being interposed in,each ease, and the studio programme was reproduced on all the speakers simultaneously. • cutting out tne other" is Mr chishoim s idea, and he emphasised mat lus scheme has no connection witn jiuno in any way, radio frequency currants are not used, and at the demonstration lus transmitting apparatus was connected directly with tne elec die lighting circuit used to conduct die auuio-uequency waves to the dqxerent loud-speakers. Questioned as to _i,e eitect ot different voltages and dniereut kinds oi current in electric mams on lus transmissions, Mr (Jinsiioim declared that the reception would ne tlie same whatever the voltage anu whether direct current or alternating current was in use. rie gave no kind of name to h's mystery box," the piece oi apparatus an whicn the working of tlie scheme nepeiuis. This consisted to outward ..ppeanmees ol a carefully-sealed cardboard box. The wire tram the walling to tho lond-speaker was in each case conducted through apertures in die sides ol this box, which was only ..iiout six inches long and three inches deep. as a further demonstration Mr Chisholm picked up the broadcast from .uaveiury on the aerial ot the station and redistributed it along the electric ■ ignting circuit to the loud-speakers. i have discussed the proposition with several well-known wireless experts, including I’ratessor Low and i>r J. ..I. itoberts, and all seemed to be tinner the impression that Mr Chisholm proposed using a high-frequency earner wave; but as Mr Chisholm denies diat lie uses any such method comment is impossible uufil he discloses aie actual technical details. Another piece of apparatus which Mr lusholm demonstrated was described oy him as “secret wireless.” This involves the use of multiple wave-lengths in transmission, and h© claims that the same speech can be transmitted on mese varying wave-lengths so that it urn Id only be picked up intelligibly on a specially-constructed set. An assistant, using the special transmitting apparatus, spoke from the studio. while in another part of the premises an attempt was made to pick up the transmission on an ordinary receiving set. Only a broken, disconnected discourse could be heard by this means, but when a "secret wireless" set was brought into use the whole speech could be detected, though the speaker’s voice rose and fell in the air-; phones and there was a disturbing clicking noise. Any number ol wavelengths up to ten can lie used in the same transmission, according to the inventor. “Secret wireless will be the utmost importance in the next war,” he declared. "ft will be impossible, owing to the multiplicity of wave-lengths, for the enemy to detect messages not intended for them. Even if they were in possession of secret wireless sets, the possible combinations are so numerous and could be so frequently changed that the utmost secrecy could be preserved.” The test was probably a rather exacting one, as the transmitting and receiving aerials were so close together. At a distance, as the inventor stated, the results would probably have been btVler.