| Show radio vision era fast approaching secret cell proves to be big step forward in television art television seeing what Is happening at a distance in the sime instant is it happens Is no longer in ita early experimental stage according to an article in kadio broadcast magazine has already been anade in england tor the commercial production of instruments for the reception of moving pictures ind J L baard the inventor of what Is ely to be a highly successful tern of television Is nightly transmit ling ills television impulses between two points in alie london area about this roan baard there Is much to say after the war he went into business with a patent sock he hid designed to keep out the damp being a scotsman he knew well that his project was no idle one fr stringent measures were bec ebsary to keep out alie eternal char of his native moors nor nas his surmise incorrect bonev was plentiful but just as matters looked rosy for him ho was forced to retire from on account of herlth throughout the davs of his business life bilal had one hobby research and to tills he turned when he becane inactive in business As far back as in 1912 he had devised a scheme for television and taeng up alie threads where he had left off it was in a remarkably short time eliat he evaa ible to transmit shadow graphs ahat Is by interposing an opaque object between a source of strong eglit and a selenium cell he was able to transmit to the distant receiver and reproduce on a screen a outline of the object at alie transmitting end not television so far so good but shadow graphs ire not television baird soon found like so many other in various countries that successful television Is a much more thing in the u of television it Is n t enough to suid mere outline of the object to be transmitted not only the contour but also nil the details and of and aliade together with a lifelike reproduction of all movements must be transmitted and received achieve this the ai of scene and light source must be reversed I 1 hat Is to say the instead of shining on the light sensitive cell must shine on the scene and under these conditions alie amount of light which actually reaches the tell is that amount which Is re fleeced fleeted from the scene baard found that the amount of light reflected from alie human face Is of alie order of one candle power only and when alie image of the face is broken up into many small parts for transmission purposes it will b realized tant alie amount of light which ac dually fall on the light sensitive cell simplicity OF RADIO by POWEL CROSLEY JR THE broadcasting EQUIPMENT alie arst piece of apparatus epp aratus that ve see than visiting a broadcasting studio Is the microphone this ms gerlous looking device Is really noth ing more alian an especially designed and highly sensitive telephone transmitter sud as one talks into when ever one carries on a conversation the telephone the transmitter anit itself Is hung by springs inside a microphone case to protect it from shocks and jars and what one sees therefore Is really the case lie little microphone being suspended inside it the sound waves in the studio are picked up by the microphone and car ried as telephonic current over regu lar telephone lines to the broadcasting itoch at the studio and uie station amplifiers consisting of radio tubes colls and other are connected to the lines to strengthen the telephonic currents at the station complicated eich equipment Is provided for gen elating alternating electrical currents of high frequency in real ltv tills equipment quip ment 1 not any more omell bated and not nearly so massive as that of tre ordinary electric power plant ahe currents generated by it ire alternating or vibrating in na bore rore flowing for an instant in one dl lection and then in the other just like the electric current in our light line they are different from the light cur rent in hint they fluctuate vibrate or change their direction of low man more times ei second to create these rapidly vi biating currents especially built somewhat resembling used in power plants may be employed ciuch simpler method and a much more satisfactory one ie to use arant cuties merely large editions of at any given moment 1 extremely small indeed caird did not find sat Is factory either the photoelectric photo electric beir or alie modern selenium cell tor his ex perl ments and so invented a cell of hta own the secret of which Is stilt close ly guarded all that Is said about it in the radio broadcast article Is that it la n cell of the type that Is one made up of extremely finely dl aided in suspension in a liquid month after month caird worked on his problem using app ir antus of the crudest description the biscula tins scaling wax string and other makeshifts beloved of the true am antor and scoffed at by the sterile pedant were very much in evidence at last lio wever in april 1925 be had the of giving the first public demonstration of television transmitting outlines between two sep J arate machines these outlines gerej not the referred to above but were transmitted by reflect i ed light a most important point showing an enormous over alie earlier experiments were 1 however very rough and and anero outlines though a few months ago baird w aai able only to transmit a object ill size of a human fact now he cin ink in a complete head and beders may remember tha during the early das of the moving picture the results on the screen wire f ir from perfect there was a constant flicker the focus as often avron vv ron and there was alev ays the pouring rain effect the images on 11 screen of from ver similar effects but hee are rapidly being eliminated until ut the present time a highly demonstration can be given perfectly clear the writer in radio broadcast A dinsdale 1 able to speak authora au thorl on this subject of pro gred for he witnessed one of baird s earll cst demonstrations and has been in close touch with developments ever since the image seen on the screen Is cleir and 1 mistakable mista lable the sitter before ife transmitter can be without the slightest difficult and evera uc tall of his features can be in even to blemishes of the complexion tomp lexion all movements are faithfully p r just as they would be on amov ie screen ev en lie smoke franr a cigarette can be seen anti its as bending wre atlis followed alie res iltis are not iet as perfect as those em on a motion rein but lucli progress diab been nude that ali writer ills no doubt that lui absolute abbo lute perfection will be it t present baird is stepping out of his labon tory as far as alie location of his belev isor Is concerned rind lie Is now engaged in broadcasting ills tele in the heart of london to a receiving sta alon at harrow about nine miles dis tint using a watt anns mitter operating on 1500 kc iiii tora these transmissions are pure of an experimental character and aie being conducted nightly after regular broadcasting hours the object of them being to perfect the technical dot ill of the transmission from a purilar wireless point of view the tubes aed in radio receiving set when connected to the proper equla ment and properly adjusted aliese bulbs of mystery act as generators alternating electric curl rent a characteristic of alese roii idly vibrating electric currents Is thata they send oft radio bodies in which they are bowing ao 10 is merely necessary to connect thise generating equipment to or system of suspended alli in the air and a considerable amount ofa energy be sent forth as radio waves the highly suspended bus tm t M tern of wires Is called aerial or aej tenna it Is like he mouth tu canies conies a loud voice calling around ali earth to radio sets atie telephonic currents from the studio are so connected to the truax equipment tant they the strength radio oice ius alie transmitting station sends ont a replica of alio telephonic currents ati chief difference being that instead at traveling along alres it ROCS space as radio baies what the click means A click should be audible in the loudspeaker when the plug Is la seated in the jick the click shows that the battery current Is reach ing the plates of the tube transformer wires or bent prongs OB the jacks arc generally lie caus of the signal not reaching the plates cause of flickering tube A flickering tube 1 caused by the arm or alre which has become passing around the I 1 hi Is remedied by removing the arm and sandpiper ing both it and the resist ance attire ocr the entire length of the rheostat where alie anu mikes contact to make a cage aerial A cage aerial consists of several wires six or echt arranged around hoops which may be from uba inches to a foot or more in diameter the several ires are continued in lh lead in which Is smaller in d cua ference than the main portion |
