Show r r f ti bo ti M Action Stability in Tube Five-Tube Set Receiver Using Basket Basket- Weave Coil Mounted Be- Be Behind Behind Be Behind hind Condensers By CAPT P V In Radio World The standard tube five-tube tuned IUt set Is shown In the diagram The I receiver uses weave basket coils colls that are mounted behind the tuning con con- condensers condensers ThIs Tills Introduces an action In the circuit which tends toward sta sta- sta stability stability Unless this were done tho tubes on the radio side would bo be uncontrollable As a n further check upon disastrous action by the radio amplifying tubes the rheostat controlling the tho two Iii HI tubes may be varied The greater the resIstance of the rheostat In the dr- dr cir circuit cult the less brightly the tube burns burnsI I and the less oscillation Fits On a 7 by 18 Inch Panel The set may be constructed on a 7 by 18 inch panel A convenIent method of assembly Is to use a socket shelf There Is just enough room for the tolls colis behind the condensers Angle Irons arc are used to secure the coils colls to the socket shelf Although called Irons they are most commonly brass brassA A tubing Is Inserted through one of the tho apertures caused by the method of winding a n weave basket-weave colL coIL This aperture formerly was occupied by a dowel stick or other rod of the wInd wInd- wIndIng windIng wind wind-Ine Ing form Inside this tubing a long machIne screw Is placed with thread toward the condenser so that a n nut may be affixed at that end to clamp the screw down upon the brass angle The other end of the angle Is affixed to the socket shelf Usually one angle bent like an I 1 L with a n short horizontal plane as the base Is sum sufficient cleat clent for each coil coll The Tho Coils Colls The Inductances are alike In con con- construction construction construction The Tho primaries have eIght turns and the have hwe turns The wire Is No 24 enameled silk covered The form diameter Is three and o l one half Inches Usually there ere are 15 Hi rods on which the wire Is wound these constituting the form The secondary Is wound for 24 4 turns then the primary wire Is pIcked up and wound along with It side by side for eight turns The primary wInding being terminated then the rest of the secondary 25 more turns Is put on The small primary Is used as a further aid In obtaining a re- re receiver re receiver celter that will not cause trouble trouble- troublesome troublesome troublesome some oscillations The set made under these directions directions with mid mCd tuning con con- condensers con con- condensers dens rs will tune approximately In Instep instep Instep step One factor that tends to op- op operate operate op operate erate against this Is the added ca- ca capacity capacity ca capacity In the first radio transformer due to the ground aerial system system system tem Thus Cl might tune with readIngs a little lower than those pt pf the other condensers To get et away from this four turns may be removed from the secondary of the first radio transformer or In the actual wInding the num numer number er of turns might be made tour four fewer vcr than that on the other 1 I I e 52 2 Instead of 50 The circuit enables one to use ear ear- earphones phones ear phones at nt the detector output but the Jack providing for this purpose Jl 31 Is to facilitate the tuning In of dis dis- distant dis- dis distant distant tant stations and not for general earphone reception On that account the rheostat that controls three tubes the the detector and two has bas audio has no auxiliary switching arrangement That ThatIs Thatis ThatIs Is when the detector tube Is lighted the audio tubes must be lighted lighted- lighted otherwise there would be somethIng wron wrong with the wiring If the diagram were the guide ulde 32 Is for Insertion of ot the plug to which the speaker cords are attached The circuit comprises two stages or of tuned radio-frequency radio tube detector an and two transformer coupled transformer transformer- coupled stages of frequency audio am amplification The Tho Tubes The tubes should be operated from a volt six-volt storage battery with 45 volts or less of ot B battery on the th detector plate and 00 on the tho RF and audio amplifier plates The Ibe set will operate fairly well on dry-cell dry tubes such as M the lOCI type but the tho ho greater volume and amplification from the large tubes make It well worth while to spend the extra amount of ot money Except with some types of i the small tubes or any cell dry cell tubes are arc not for tor a n perma- perma Q QIA I leD leDI loo IA I IAaN a aN a m 4 u u N J ji N NJ JI c 1 r ri i I Circuit Diagram of Standard Five Five- Tube Five Tube Tubo Tuned RF Set nent neat set because In time the radio user goes over OTer to the volt five tubes because of their more satisfying servIce service service ice The following parts ports will be needed Three radio-frequency radio transform transform- transformers ers weave basket transform transform-II Three variable con con- condensers condensers condensers 01 Cl One 7 by 18 Inch panel One 2 by 17 Inch socket shelf with five sockets Two ten-ohm ten rheostats One double-circuit double jack Jl One single Jack 32 One 2 meg grid leak lenk One grid condenser Two frequency audio-frequency transformers Three Inch four-Inch dials Three dial pointers One A battery switch |