Show edited by 0 doublas editor of 2 p awai cox F V I 1 V only the audio frequency tube Is P 70 AV vol I 1 av J i four amplifications amplification by ARTHUR H EDDY if you engage yourself in conversation with the lie average cur concerning tits his radio recell ng set it will not bo be long before lie vill mill bring up tip th the question of maximum range of reception cep tion which would bo be tile the paramount topic of discussion jt Is thul that we have grown into the habit of judging the relative merit of t q receiving set by the lie range that it can cover and although tills tia method of judgment la Is not altogether fair find and just to all types of outfits yet for tile tho average beginner or radio experimenter it does docs form n good badts of 0 quality the standard range of 0 tile the regenerative receiver la ii quite on an uni un known quantity for amateurs and exports having almost identical circuits and antenna conditions give very con 1 filleting Ill eting claims cut but still it wo we are to 0 o base most of our claims on distance on everyday possibility of receiving a certain broadcasting station it would bevery benr tho the truth if f we should limit the regenerative receiver to approximately a range of miles when using a rather sensitive detector abe tube I 1 most amateurs realizing this have endeavored to nu augment intent tills distance by the use of a combination of audio and radio frequency amplifiers in other words jhb he reflex circuit tile the former type success was fissured assured where the ac sensitivity of lie detectors detector was great enough to detect the signal but since tho the sensitive tube must be a soft tube that Is a tube that hisses at a i critical point the number of audio frequency stages Is somewhat limited to adapt radio frequency amplification to a regenerative receiver beiver after once it has been constructed ted Is by no means an easy task yet some amateurs have not only accomplished complis hed this but havo have obtain obtained ed re markab lq results 1 for the vast majority of beginners the true answer to tal the problem of building a long distance dla tonce receiver Is not the regenerative receiver with cuillo and radio frequency amplifiers nor the pe celver but a receiver which Is a combination of audio band and radio frequency units in tile the circuit tills this type of circuit will not only have the desired range but will be so compact that it will bo be readily portable and an simple and in its operation that the beginner can operate it ns as the expert reflex Ilc flex Is not new but Is usually described in peculiar ways with peculiar names tills this Is at once nn an evidence of evasion tor for the simple reason that at the end 0 of f th the story the whole thing will be found to be the original reflex circuit A reflex set can be made from it single tube and crystal detector the single tube serving for both audio and radio frequency amplification if it Is desired to operate a loud speaker ipen ker we must res resort ortto to a two or three tube reflex circuit hero here the first two tubes serve as radio amplifiers and flers with the crystal as detector the schematic diagram shows a number tube reflex cirl carus N aits if amplifier tubes are used in nil all stages the 11 battery should be jegu abed so that the proper B battery voltage Is applied to their respective plates plate s this Is accomplished accomplish eh by experiment perlin peri ment en L usually between forty five and seventy volts are arc boand best for the plate in the actual application odthe of the circuits there are several difficulties to be overcome tie the tubes for instance roust be coupled for both radio unit and audio frequency amplification but placing ng the audio frequency amplifier in a circuit where bidlo frequency currents are flowing the windings of the secondary act as a choke coll and prevent the r radio frequency currents from passing to overcome verome tills a condenser I 1 Is shunted hunted around ali ae windings jo BO athe the from two vacuum tubes radio frequency currents may pass it Is suggested that boia tubes ho be used in fit nil all reflex circuits since tills tube responds to radio frequency currents much better than others if tills this tube Is used it would be advisable to employ a CO 50 olim ohm rheostat in the event that a six volt battery Is used I 1 the constructor attempting to build either of these sets should not employ direct regeneration once the tube starts oscillating the whole set may become paralyzed due to the choking of chii ho tubes different types of tubes have various effects with the transformers transform eri employed in the set et there are a number of good radio frequency transformers now anthe on the market at times it la Is best to employ a high ratio audio transformer in the A with chils his typo of set act either loop or aerial may bo be used if the tube spills over reduce the values of the he capacity in shunt to tho the of tho the windings of tile lie transformers in using the tubes it will be found that roost most of of the tuning timing will be done by tile the uso use of if the rheostats potentiometer and condenser in shunt to loop new york herald radio appreciated by those who cannot see in lieu hen of the inspiration which the artist derives from the upturned up turned expectant bacch of her audience the sing shig or er at of tho the radio bron costing station it if sho she has pagination can call picture hundreds of howes where sit bit invalids blind men and women and even many leaf deaf people thrilled at her every note letters which come to the ralin radio broadcasting stations tho the enjoyment velch the stay rit at homes got from broadcast music to many of them air entertainment Is the only pleasure that breaks the monotony ot of passing time to many radio brings for a tittle time at least forgetfulness of suffering one such letter Is that rec received elvel recently by station at schenectady N Y from a young blind woman who lives in seneca falls N Y site she was graduated front from college after working her way through aided by the limited means of her parents willie taking a years work i in normal school to fit herself tor for tP teaching achIng a n serious illness brought oil blindness she lad had to provide a living for herself her aged father and mother and she heense hem me n masseuse writing to khe ehe says 1 if you could know how i much n ucla we M 9 enjoy the voice of the schenectady 11 station you would he be glad that god gave you cuch a gift mcfather my father who Is very hard of hearing can hear bear you distinctly and knows your voice ill ready altho digh wo we ore are pilly only two weeks lold ln la the world Fat father lier could get nearly nil rill tho the service and song snug the hymns with tho the choir the work of massage Is so very exhausting eill austing that even when ft hen there la Is nn an invitation to get some recreation nuon physical weariness makes it impossible to enjoy anything tho the constant association social loh with sick people the worry of bf expense ond find the strain of trying to do things thine without sight the care of a f father 11 titer who lna las been feeble h A for long A lit time ne and the anxiety or of A mother seventy four yearl year old who has ir b ad to works so hard to serve a deaf husband band and mind blind daughter nl all these things broucht mo me to a dreadful state of mind dis dist trusting everybody anti and sorry orry for masef ms mv iselt sef elt no honors conferred on in a iele celebrity brity could hove have given greater pleasure than the church service gave i two awo people one deaf and tho the other blind and hungry for something good and helpful 1 I 1 do chilt some philanthropist who would like ake togo to do something for nd would furnish radio oeta be t 8 t to a those who s less ihan I 1 V |