Show to 0 merchandising rd led b CRYSTAL ardnt 1 1 0 fit abill a 0 0 0 arrangement of a varl ometer and a varia varla set got illustrated include includes 8 6 mple ble condenser Con denier CRYSTAL atoll this circuit although not different from many other others has ha enjoyed ro R mark ablo Suc 9 amoni among the great army of radio fans fant in lie tile world toda lodai tl if ere pre are hundred hundreds still using crystal type receivers there Is 1 a reason for this til A good crystal la Is perfect in reproduction of voice and music the crystal set requires no batteries and I 1 therefore he has no upkeep expense for one who nho geels reception over abort short distances of about fifty miles a met of this kind li is more than tory there are many fan fans owning receivers who still keep their crystal sets for local reception the th clear natural tones ara pleasant change from the ion lots I 1 to speaker N no 0 harm will result if nou ou hile 1 H little snooze for there are tire no batteries to run down and no tubes to turn out selectivity limited the principal objection to the cras tal set la Is the lack of it lack lacks the power of the tube receiver to cut one station statton in and another out if necessary tuning devices are that are essential to make a set selective the aps stance created seriously impairs the volume and ebor shorten teni the range I 1 he energy aed bcd in a radio set Is I 1 sin ill if all that ii h accurse it ile I 1 on the aver age antenna in a years time were col feted into one charge it would not be sufficient to light a flashlight bull built it Is so 10 small there are no instruments delicate enough to accurately measure it it 11 Is to therefore necessary to con berye all the energy possible there are several methods that may be b used to make a costal set tive these thee ere are loose coupling of the tuning inductances if t e use of several variable condenser condensers or adding a wave trap arrangement alde from being added expense pense these methods are not wholly holly efficient one result Is obtained through the sacrifice of ar another lother characteristics of set the set bet shown la Is a simple arrangement of a varl ometer and a variable condenser this circuit although not basically different from many others has his enjoyed remarkable success it has good selectivity good volume and an exceptional recell receding rec ehing ng range in some cases it has been possible to operate a loud speaker on nearby stations and distances of five live to seven hundred miles have been beard on the phones the results are all that could be expected from a crystal rec receder elier the reason for this Is it has ling both inductive and CR tuning and practically no louses all taps and sliders characteristic of most crystal sets have been abolished and worl mani mansilp blis and materials of or vacuum tube quality have been used through gli out it Is the usual practice to build a crystal set et as cheaply as possible accounts for at least four fifthe of the trouble experienced with crys tal tit sets and Is responsible for the limitations put on bets of this one expect a tube set el to in work nork efficiently with a crude tapped lapped toll oil and junk parts so it Is hardly lug log leal ical to expect it of a canal fet set lie ile tore fore the days of tue luse rec clur the tile amateurs built crystal bets et 0 o bood apparatus and got results that mould we make ke many owners of tube sets today envious ibis mn lan be done nr no as ell as it was done then all that Is necessary it 1 to get good parts be careful to book them up as shown and use an antenna and round ground as described bed antenna ground parts the antenna should be of the single wire type about 1 feet long it should be run in a perfectly straight line use only one ire and no el angles glee A lre of abo about 0 o 14 gauge Is all right for this purpose the illie ground Is just as important as the an tanna although it Is the one item gen ten trally glen the least consideration the bet best ground la Is one connected to several objects such as is a wafer pipe radiator metal stake arlen in the ground gas pipe PIK etc in this manner a 10 low reUt mc round ground Is 13 sure to be b Q emi L I 1 obtained an tin I 1 nill all retain if it a value under noder all conditions I 1 ahe he length of the ground round lead makes little difference it may be 0 O feet lont long if it necessary use a it large gauge gange wire I 1 ou may use us if more I 1 ahr he part parts necessary ne essary to construct the set are a as follow fol loAl one vart omeler a should ou have ave a about out 80 turn turnis on b th rotor totor and stator one 00 I 1 variable on denser about 43 plates one variable crystal cn stal detector tie n aeten by nine panel blasel oard I 1 undine posits screw wire ire etc boston traveler describes simple tester for circuit continuity by F C MADDOX I 1 have assembled a very simple teat test outfit made up from odds and ends around the work shop which alch helpa helps considerably in tit determining whether parts and laboratory olds old sin I 1 ends are e or not it has hail iilo alo been found useful in testing le tnT out radio sets for continuity of circuit testing fixed flied and ari allf for short circuits jack jacks and sockets fir for loose connection and transform era ers for short circuits circuit open circuit una fuses ra 25 harrip test terminals temi nals I 1 IOV liput use work tea its test outfit may be B made mide up from odd odds and end ends and ground round this teat test unit consists con slite of a 25 watt lamp inserted in one ilde side of the volt line to which are connected a to awls the test leada leads ere are of flexible wire two fuse sockets and fuses are inserted one in bacu tilde of the line at iti its input the circuit diagram ie in shown in be the allu illus ahe lamp flashes when a circuit la in closed india indicating ting that the circuit of the unit tested Is continuous a in test lag addio transformers the awl wi points are touched to the primary posts and if the secondary ilde side Is momentarily short circuited a spark discharge may be observed at its terminal terminals must use care to keep vacuum tube tubes in order to prolong the life of vacuum tube tubes they should be burned as dimly as a los possible sIble ble at all timea times fila ala ment current and plate voltage have the vt of destro Inc the coating 0 of thor thorium luni on ou the filament if the he operator finds that the tube has to be burned brightly and the plate voltage must be over DO 00 for good volume the tube should be taken buck back to the place vi where it was viale t purchased and a te test 11 I 1 made should one find that it Is 11 1 lm M possible to buesa gue at the proper bril a voltmeter olt meter should be added to the tile set do not ue ute steel or iron iran aliben len mounting inductances of aay any ton sort avoid the tho use of steel or iron brackets these metals impair the efficiency of the inductance by the I 1 introduction n tro of magnetic metal metals into the thes field mill of the this coll use t brau becketa bruC keta ast |