Show I I I I I I II 0 0 A a FIg 3 The Above Shows Diagram Proper Connections for the Antenna Coupler and the Radio Frequency Transformer By PETER MOMBELLO In New York Tribune Herald Tribune Herald Tribune Very often orten a radio set especially If It Is one of o the popular radio frequency radio type will not work very well on DX stations even after the fan has lins taken great care caro In making tile the proper ar- ar arrangement arrangement ar arrangement of ot coils colls spacing solder soldering In etc This Tills Is very often duo due to the fact that the set builder does not reco recognize any difference In the way that the four leads from the tuned couplers and audIo transformers are connected It should be pointed out that every coil In a n set Is at a high potential at atone atone one end and at nt a low potential at the theother theother theother lone other end This potential potential difference dIfference Is IsI necessary for a flow of electricity For I example In a primary coil coll the end con con- connected connected connected to the aerial Is at a high po- po po potential tE-nUal tE while the side connected to the ground Is s at a low potential A current can thus flow How through this coil coli from the side of or high potential to the side of ot low potential In so doing a magnetic field I Is set up about the coil which Is constantly rising and falling with the reversals of the radio fre quency currents flowing through the prImary since this Is an oscillating cIr cIr- cIrcuit dr cir circuit cult The changes In the the the magnetic J V Fig Showing 1 1 Showing the Primary Circuit I incorrectly Connected I Ifield field Induce a current In the secondary secondary second- second secondary ary coil coll which also changes direction I as many times as there are reversals In the primary coil coll Potential Difference In Coil CoilLet I Let us now go back to our dea of I potential difference dl In a coil coll The Idea Idea of or potential Is relative A con con- conductor con i I reI I ductor It t at a high potential with re- re respect respect re respect to some other part of the cir clr- circuit circuit cult which may be grounded and thus will be at a low potential Also it has lias been heen shown that the end of or a coil which Is farther away from the source of or current Is the side of hl higher her potential Thus In the secondary coil coli the end that Is farther away from the primary Is the end of or higher potential I anta Ad Advantage e should be Le taken of this fact and the proper connections made on ona ona ona a coupler so that the lie current from the aerial will pow flow through smoothly from end to end without any losses and that th the end whIch Is s at the highest potential should be connected to the Fig How 2 2 How the Secondary Circuit Is IsI I Incorrectly Connected grid which Is to have the greatest force Impressed upon It That Is the facts shout about 1 hout differences In n potential In Ina Ina Ina a coil coll should be applied Mistakes In Connecting Figs 1 and 2 show the usual mis- mis mistakes takes tales that are made In connecting couplers In Fig 1 the side of or the high potential aerial end Is connect connect- connected connected ed next to the low potential side of the secondary In Pig Fig 2 the low po- po potential po potential side of the primary ground end is connected so that the grid side of the secondary Is next to It The fault here Is that the grit grid Is not In- In insulated In Insulated from a low potential influence Both of or these Improper connections ons Cause losses which are noticeable onD on DX D stations fhe They result from a mis mis- misinterpretation interpretation of diagrams which are drown drawn In a n way that will be very com com- compact compact compact pact and neat In appearance but the connections shown are arc not to tn t be bc made madeus us as If the diagram were an actual pic pic- picture picture ture of the apparatus It would be will wILli t ti all exi experimenters drew nil their diagrams such as the one In FIg Fie 3 Then no mistakes could be made In Inthe inthe Inthe the coupler connections which would save a great deal of or experiment In re reversing re- re reversing connections continually utter after a set Is completed Fig 3 shows the proper connections for tor a coupler The low potential side or of the primary ground end and the thelow thelow I low potential side of the secondary filament end arc are placed together so that no leakage can occur The Im- Im Important important Im Important thing to remember Is to con con- connect the side farther away from the prImary coil coll to the grid as shown In the Intermediate stages of ot radio- radio B Fig Transformer 4 4 Transformer Should Have Ter- Ter Ter Terminals Marked as Shown frequency amplification the couplers are connected In the same way the lead from the plate being treated as asIf asif asIf If It were the lead from the aerIal and the connections of ot hl high h and low potentIals are based on this the plate being at as us high potential as the aerial To Tu Save Making Reversals In the case of ot frequency audio trans trans trans- transformers transformers formers the same rules hold true Most transformers have their terminals clearly marked but If it this tills be not the case the fan should carefully examIne I the i i windings and leads to determine the high Mid and low potential sides Even If the leads are marked It Is worth worthwhile worthwhile while to check them up and be sure that they are correct before connecting them so as to save trouble In makIng reversals The secondary Is the out out- outside outside outside side winding In the transformer It being wound over the primary Md ad having two leads The rhe lead from the outer turns Is farther away from the source which Is the primary and hence must be connected to the grid since It Is the side of ot the highest po- po potential potential po potential |