Show M ilk F P P COIL C 0 COIL P P if P 4 A aw five tube tuned radio frequency receiver usino using low lose lor doughnut coils 0 oy y CARLTON E BUTLER associate member institute of arh miti american institutor of r tin tuni ti radio frequency lape of t set get employing two stages slakes of u tuned d I 1 anllo frequency fie quency detector defector and two wo stage blanch ni r low ralo arv quelley iuliu it iffat loll 1011 Is 14 going to tn be fur fill and ni tile most broad vil sting fueher for tins tho col umang lillig sennon this Is liin diw largely to ti tilt the fidot that the ibe it lc lokim nl or dl tile voll coll for I 1 ciolli ill ir liters and is ims flow iio reli tIled tile llie ml fill miah nl nige w hero imy nil it or of ill tin auld rel 4 of tile radl 0 fresilli frei illi m me malsi their I 1 s lalli are not new nem sonio of ali he best talent tit in the ilic uni led stilted europe ailts lilts been 1 H on oil tin in for chiev or ir folly foil glnn re as st bellied vel lied il it i li be sollie honn I 1 could llad lint lie he prot wed d their ili ID radio rvin rt irs ers fill tills or ol higi losses if III file oil fluff 1111 tit tin gaii en ants ebig gow Kill ird ii icv 1 ite ll 11 pecullar biti aillar shape of if tills this ailts lilts allow IKI beell in ill tin ill now flow low loss hiss fiill 1 11 designed ly by frank one id if the plo in ili tile anillo engineering field by b tile lie w of stagger 1111 ling shows lowest loss tile alio stagg douglin tit coil oil not onla of fly liny tile adan tuge if nil fit tn en closed magnetic held liidi prevents iric ntH Inter coupling but it also shows lle lowest loss of tiny coil fill now flow on oil the lie market tile enclosed hold field ly elani acs tile pl pacu cu of stray signals find static by the lie set HI itself these dinean that lint the HIP ron mn of a frequency sit till doughnut colts colls will produce a receiver that t VO volume it I 1 e amazing selectivity select I 1 alt ii fill and it 11 much liel ilet ter tone quality than limn Is milly ol ob willi it 11 set c this type lipe until the lie Int introduction lion of if flip lip farold coll coil into file construction of tuned radio frequency receivers anost till nil of the gets bets were hullt dillong illon flip lines till great rent stress hild on oil hie flip if nd flin of of anak ing the re epler hanble in ili iier pv rallon liu by 1 preventing os used it small hilan chig ann aden er liten licen lie ahe grid of mol till plato of the lie pro wedIng illers used a potentiometer air if imsano ing ri sIsIn nce of some sirl in hie ili plate cir lr cult UK of tile radio without or of loine sort the ncr iio tube set of ills tic Is 11 useless in ili fill mal whistles when titre alie celer Is full tuned to the wave length of it 11 the mi mile hole le function of tit lie auxiliary Is to add losnes of 01 ce to tile circuit to bring tile cotal amoline of energy down don below tin the I 1 point of the receder I 1 if the lie same circuit bouli lie he so go nr ranged that tile lie limits fields of r tile hie chith could be bi danced ed and lit in it manner that no inter aling of if ill lie magnetic fields of hie file colln coils would tulie place the volume lit and range of the receiver would increase wonderfully the tone quality would akoi lii irie with the absence of if the lie ippo p ratus vils li 14 exactly klinl hat Is 14 done in the lie receiver described in tills article through tit lie use lisp of 10 low bog doughnut coils which lil alnie gel f con tallied wilned magnetic fields tle lils and so interaction inter action of ill the colls coils ind it Is for this renson reason that it Is sary eary to mount tit lie foils its nt fit hlll al angles to mold avold whistling alil and howling in practice the HIP colla coils may be placed side bide by side aide without Alt hout tin nn noticeably notice ablo effects As aie magnetic field I 1 unil rely closed no pic kill effect Is without the aerial and ground aind no static or signals will lie in reeked except on the exact hiie to td alili ill the receiving la Is tuned lails antl it on an ideal summer rT oteler eler and it car he be its used near if nm erful broadcasting without interference parts needed to build tile the receiver ou off will ill need the following parts 1 coupler low loss doughnut kill 2 to lm lo los s doughnut lullu 3 low lo 10 loss enri able ali condensers or of XH liard cu a pm it 2 3 1 I lo lit I 1 nit to dudlo frequency trans is A ful v fiO fiolo sock lH pill 11 ll ive U 25 i ann if the C 01 A t apo of if lulu lithe Is 14 to alp lx used Ill is 11 operation 1 un l in he simplified by using ii it ii 25 5 ia ilk 1111 still to 11 control 1114 to ONO inilla fr iorii ii rii hubei fill 1 6 I olmi i in i nil I 1 ani m ili alio doe klo clor and two tm 1111 di fill S I 1 befth tile foll ming liked 11 in 1 I ludd tk wa ml bild I 1 if t enfil IV I 1 nicil 1 2 1 nil ilni grid 1 l id aenk 1 lynli i in nil lili lick J ts ln ro iii 1111 A screws nia piti ili li if alln IM or if nee heeled led TI 1 I lir I 1 I 1 imal ansi III 0 the re receiver ceiNer nr clur ill ir 10 the 1 lie r mi fill easily tie he alil iii if 11 i 1 wil K li painel 1 1111 alir i 24 or 26 kinli aich lomel wu lie he used if desire |