Show forefathers forefather S OF RADIO by GEORGE LEWIS of the creley radio corporation while wireless telegraphy soon became quite well established communication across the atlantic ocean being proved practical as early as 1001 1901 it remained for an american to make the developments which made radio telephony possible lee deforest was that american he developed the audion aud lon I 1 lee deforest de forest radio tube noy in almost universal use its as a detector and amplifier of radio signals and as a generator ot of oscillations it at the transmitting station due to certain technical difficulties it was impossible to send voice by radio from transmitting stations using the old marconi equipment the radio tube as developed for power purposes radio tubes that are used in the modern sets supplied a current however which could be used as a carrier for voice and music As developed for receiving purposes the radio tube may be used as a detector replacing the crystal of picard and the of marconis apparatus as a means of making the received current capable of operating headphones nes additional tubes amy be used us as amplifiers their action bein being 9 that of relays releasing current from local batteries when acted upon by the signal thus the typical radio set of today employs a detector tube together with one or more additional tubes as amplifiers it Is customary to distinguish between tubes used to amplify the current before it passes through the detector and those used to amplify it after it passes through the detector by calling the former radio frequency amplifiers and the latter audio audelo fre quency amplifiers |